from reportlab.lib.pagesizes import A4
from reportlab.lib import colors
from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
from reportlab.lib.units import mm, cm
from reportlab.platypus import (
    SimpleDocTemplate, Paragraph, Spacer, Table, TableStyle,
    HRFlowable, PageBreak, KeepTogether
)
from reportlab.platypus.tableofcontents import TableOfContents
from reportlab.lib.enums import TA_CENTER, TA_LEFT, TA_JUSTIFY
from reportlab.pdfgen import canvas
from reportlab.platypus import BaseDocTemplate, Frame, PageTemplate
import os

OUTPUT_PATH = "/tmp/workspace/ecg-guide/ECG_Complete_Guide.pdf"

# ── Colour palette ────────────────────────────────────────────────────────────
RED       = colors.HexColor("#C0392B")
DARK_RED  = colors.HexColor("#96281B")
NAVY      = colors.HexColor("#1A2E4A")
BLUE      = colors.HexColor("#2980B9")
LIGHT_BLUE= colors.HexColor("#D6EAF8")
TEAL      = colors.HexColor("#148F77")
LIGHT_TEAL= colors.HexColor("#D1F2EB")
ORANGE    = colors.HexColor("#E67E22")
LIGHT_ORANGE = colors.HexColor("#FDEBD0")
PURPLE    = colors.HexColor("#6C3483")
LIGHT_PURPLE = colors.HexColor("#E8DAEF")
GREEN     = colors.HexColor("#1E8449")
LIGHT_GREEN = colors.HexColor("#D5F5E3")
YELLOW_BG = colors.HexColor("#FEF9E7")
GRAY_LIGHT= colors.HexColor("#F2F3F4")
GRAY_MID  = colors.HexColor("#BFC9CA")
WHITE     = colors.white
BLACK     = colors.HexColor("#1C1C1C")

# ── Styles ────────────────────────────────────────────────────────────────────
styles = getSampleStyleSheet()

def style(name, **kw):
    s = ParagraphStyle(name, **kw)
    return s

TITLE_STYLE = style("MyTitle",
    fontName="Helvetica-Bold", fontSize=28, textColor=WHITE,
    alignment=TA_CENTER, spaceAfter=6, leading=34)

SUBTITLE_STYLE = style("MySubtitle",
    fontName="Helvetica", fontSize=13, textColor=colors.HexColor("#D6EAF8"),
    alignment=TA_CENTER, spaceAfter=4, leading=16)

CHAPTER_STYLE = style("Chapter",
    fontName="Helvetica-Bold", fontSize=16, textColor=WHITE,
    alignment=TA_LEFT, spaceAfter=4, spaceBefore=4, leading=20)

SECTION_STYLE = style("Section",
    fontName="Helvetica-Bold", fontSize=12, textColor=NAVY,
    alignment=TA_LEFT, spaceAfter=3, spaceBefore=6, leading=15)

SUBSECTION_STYLE = style("Subsection",
    fontName="Helvetica-Bold", fontSize=10.5, textColor=TEAL,
    alignment=TA_LEFT, spaceAfter=2, spaceBefore=4, leading=13)

BODY_STYLE = style("Body",
    fontName="Helvetica", fontSize=9.5, textColor=BLACK,
    alignment=TA_JUSTIFY, spaceAfter=3, leading=14)

BULLET_STYLE = style("Bullet",
    fontName="Helvetica", fontSize=9.5, textColor=BLACK,
    alignment=TA_LEFT, spaceAfter=2, leading=13,
    leftIndent=14, bulletIndent=4)

BOLD_BODY = style("BoldBody",
    fontName="Helvetica-Bold", fontSize=9.5, textColor=BLACK,
    alignment=TA_LEFT, spaceAfter=2, leading=13)

TABLE_HEADER = style("TH",
    fontName="Helvetica-Bold", fontSize=9, textColor=WHITE,
    alignment=TA_CENTER, leading=12)

TABLE_CELL = style("TC",
    fontName="Helvetica", fontSize=9, textColor=BLACK,
    alignment=TA_LEFT, leading=12)

TABLE_CELL_C = style("TCC",
    fontName="Helvetica", fontSize=9, textColor=BLACK,
    alignment=TA_CENTER, leading=12)

CAPTION_STYLE = style("Caption",
    fontName="Helvetica-Oblique", fontSize=8.5, textColor=colors.HexColor("#555555"),
    alignment=TA_CENTER, spaceAfter=4, leading=11)

WARNING_STYLE = style("Warning",
    fontName="Helvetica-Bold", fontSize=9.5, textColor=DARK_RED,
    alignment=TA_LEFT, spaceAfter=2, leading=13, leftIndent=10)

# ── Helper functions ──────────────────────────────────────────────────────────

def chapter_header(title, color=NAVY):
    """Returns a styled chapter header block."""
    tbl = Table([[Paragraph(title, CHAPTER_STYLE)]], colWidths=[170*mm])
    tbl.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,-1), color),
        ("ROUNDEDCORNERS", [4,4,4,4]),
        ("TOPPADDING", (0,0), (-1,-1), 7),
        ("BOTTOMPADDING", (0,0), (-1,-1), 7),
        ("LEFTPADDING", (0,0), (-1,-1), 12),
    ]))
    return tbl

def section_box(title, color=LIGHT_BLUE, tcolor=NAVY):
    s = style("sb", fontName="Helvetica-Bold", fontSize=11,
              textColor=tcolor, alignment=TA_LEFT, leading=14)
    tbl = Table([[Paragraph(title, s)]], colWidths=[170*mm])
    tbl.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,-1), color),
        ("TOPPADDING", (0,0), (-1,-1), 5),
        ("BOTTOMPADDING", (0,0), (-1,-1), 5),
        ("LEFTPADDING", (0,0), (-1,-1), 10),
        ("LINEBELOW", (0,0), (-1,-1), 1, tcolor),
    ]))
    return tbl

def info_box(text, bg=YELLOW_BG, border=ORANGE):
    s = style("ib", fontName="Helvetica", fontSize=9.5, textColor=BLACK,
              alignment=TA_LEFT, leading=13, leftIndent=4)
    tbl = Table([[Paragraph(text, s)]], colWidths=[165*mm])
    tbl.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,-1), bg),
        ("BOX", (0,0), (-1,-1), 1.2, border),
        ("TOPPADDING", (0,0), (-1,-1), 7),
        ("BOTTOMPADDING", (0,0), (-1,-1), 7),
        ("LEFTPADDING", (0,0), (-1,-1), 10),
        ("RIGHTPADDING", (0,0), (-1,-1), 10),
    ]))
    return tbl

def bullet(text, indent=14):
    return Paragraph(f"<bullet>&bull;</bullet> {text}", BULLET_STYLE)

def subbullet(text):
    s = style("sb2", fontName="Helvetica", fontSize=9, textColor=BLACK,
              alignment=TA_LEFT, leading=12, leftIndent=26, bulletIndent=16)
    return Paragraph(f"<bullet>&#9702;</bullet> {text}", s)

def sp(h=4):
    return Spacer(1, h*mm)

def hr(color=GRAY_MID, thickness=0.5):
    return HRFlowable(width="100%", thickness=thickness, color=color, spaceAfter=2*mm, spaceBefore=2*mm)

def make_table(headers, rows, col_widths, header_bg=NAVY, alt_bg=GRAY_LIGHT):
    header_row = [Paragraph(h, TABLE_HEADER) for h in headers]
    data = [header_row]
    for i, row in enumerate(rows):
        bg = WHITE if i % 2 == 0 else alt_bg
        data.append([Paragraph(str(c), TABLE_CELL) for c in row])
    tbl = Table(data, colWidths=col_widths)
    style_cmds = [
        ("BACKGROUND", (0,0), (-1,0), header_bg),
        ("ROWBACKGROUNDS", (0,1), (-1,-1), [WHITE, alt_bg]),
        ("GRID", (0,0), (-1,-1), 0.4, GRAY_MID),
        ("TOPPADDING", (0,0), (-1,-1), 5),
        ("BOTTOMPADDING", (0,0), (-1,-1), 5),
        ("LEFTPADDING", (0,0), (-1,-1), 6),
        ("RIGHTPADDING", (0,0), (-1,-1), 6),
        ("VALIGN", (0,0), (-1,-1), "MIDDLE"),
    ]
    tbl.setStyle(TableStyle(style_cmds))
    return tbl

# ── Page callbacks ────────────────────────────────────────────────────────────

def cover_page(canvas_obj, doc):
    canvas_obj.saveState()
    w, h = A4
    # Background gradient simulation with rectangles
    canvas_obj.setFillColor(NAVY)
    canvas_obj.rect(0, 0, w, h, fill=1, stroke=0)
    # Top accent bar
    canvas_obj.setFillColor(RED)
    canvas_obj.rect(0, h-12*mm, w, 12*mm, fill=1, stroke=0)
    # Bottom accent bar
    canvas_obj.setFillColor(TEAL)
    canvas_obj.rect(0, 0, w, 8*mm, fill=1, stroke=0)
    # ECG waveform decoration (simplified)
    canvas_obj.setStrokeColor(colors.HexColor("#E74C3C"))
    canvas_obj.setLineWidth(2)
    canvas_obj.setFillColor(colors.HexColor("#E74C3C"))
    # Draw a simple ECG trace across the page
    y_base = h * 0.42
    pts = [
        (10, y_base), (50, y_base), (60, y_base+5), (65, y_base-30),
        (70, y_base+60), (75, y_base-30), (82, y_base+8), (90, y_base),
        (130, y_base), (140, y_base+4), (148, y_base-12),
        (155, y_base+4), (165, y_base), (210, y_base),
        (220, y_base+4), (228, y_base-12), (235, y_base+4), (245, y_base),
        (290, y_base), (300, y_base+5), (308, y_base-30),
        (313, y_base+60), (318, y_base-30), (325, y_base+8), (333, y_base),
        (375, y_base), (385, y_base+4), (393, y_base-12),
        (400, y_base+4), (410, y_base), (455, y_base),
        (465, y_base+5), (473, y_base-30), (478, y_base+60),
        (483, y_base-30), (490, y_base+8), (500, y_base), (595, y_base),
    ]
    p = canvas_obj.beginPath()
    p.moveTo(pts[0][0], pts[0][1])
    for x, y in pts[1:]:
        p.lineTo(x, y)
    canvas_obj.drawPath(p, stroke=1, fill=0)
    canvas_obj.setStrokeColor(colors.HexColor("#2980B9"))
    canvas_obj.setLineWidth(0.5)
    canvas_obj.setFillColor(colors.HexColor("#2980B9"))
    y_base2 = y_base - 50
    pts2 = [
        (10, y_base2), (50, y_base2), (56, y_base2+3), (60, y_base2-18),
        (64, y_base2+36), (68, y_base2-18), (74, y_base2+5), (80, y_base2),
        (120, y_base2), (126, y_base2+3), (130, y_base2-18),
        (134, y_base2+36), (138, y_base2-18), (144, y_base2+5), (150, y_base2),
        (595, y_base2),
    ]
    p2 = canvas_obj.beginPath()
    p2.moveTo(pts2[0][0], pts2[0][1])
    for x, y in pts2[1:]:
        p2.lineTo(x, y)
    canvas_obj.drawPath(p2, stroke=1, fill=0)
    canvas_obj.restoreState()

def normal_page(canvas_obj, doc):
    canvas_obj.saveState()
    w, h = A4
    # Top bar
    canvas_obj.setFillColor(NAVY)
    canvas_obj.rect(0, h-10*mm, w, 10*mm, fill=1, stroke=0)
    # Header text
    canvas_obj.setFont("Helvetica-Bold", 8)
    canvas_obj.setFillColor(WHITE)
    canvas_obj.drawString(15*mm, h-6.5*mm, "ECG COMPLETE GUIDE: Disorders & Interpretation")
    canvas_obj.setFont("Helvetica", 8)
    canvas_obj.drawRightString(w-15*mm, h-6.5*mm, "Orris Medical Reference")
    # Bottom bar
    canvas_obj.setFillColor(NAVY)
    canvas_obj.rect(0, 0, w, 8*mm, fill=1, stroke=0)
    # Page number
    canvas_obj.setFont("Helvetica", 8)
    canvas_obj.setFillColor(WHITE)
    canvas_obj.drawCentredString(w/2, 2.8*mm, f"Page {doc.page}")
    # Left accent line
    canvas_obj.setFillColor(RED)
    canvas_obj.rect(0, 8*mm, 3*mm, h-18*mm, fill=1, stroke=0)
    canvas_obj.restoreState()

# ── Build content ─────────────────────────────────────────────────────────────

def build_pdf():
    doc = SimpleDocTemplate(
        OUTPUT_PATH,
        pagesize=A4,
        rightMargin=18*mm, leftMargin=22*mm,
        topMargin=18*mm, bottomMargin=16*mm,
        title="ECG Complete Guide: Disorders & Interpretation",
        author="Orris Medical Reference",
        subject="ECG Interpretation for Clinical Practice",
    )

    story = []

    # ═══════════════════════════════════════════════════════
    # COVER PAGE  (uses cover_page callback via first page)
    # ═══════════════════════════════════════════════════════
    story.append(Spacer(1, 45*mm))
    cover_title = style("ct", fontName="Helvetica-Bold", fontSize=34,
                        textColor=WHITE, alignment=TA_CENTER, leading=40)
    cover_sub   = style("cs", fontName="Helvetica", fontSize=15,
                        textColor=colors.HexColor("#AED6F1"), alignment=TA_CENTER, leading=20)
    cover_tag   = style("ctag", fontName="Helvetica-Oblique", fontSize=11,
                        textColor=colors.HexColor("#A9DFBF"), alignment=TA_CENTER, leading=14)

    story.append(Paragraph("ECG Complete Guide", cover_title))
    story.append(sp(3))
    story.append(Paragraph("Disorders &amp; Interpretation", cover_title))
    story.append(sp(8))
    story.append(Paragraph("A Systematic Reference for Medical Students, Nurses &amp; Clinicians", cover_sub))
    story.append(sp(35))
    story.append(Paragraph("Covering: Normal ECG · Arrhythmias · Conduction Blocks · Ischemia / MI", cover_tag))
    story.append(Paragraph("Hypertrophy · Electrolyte Disorders · Drug Effects · Systematic Approach", cover_tag))
    story.append(sp(10))
    cover_byline = style("cby", fontName="Helvetica", fontSize=10,
                         textColor=colors.HexColor("#85C1E9"), alignment=TA_CENTER, leading=13)
    story.append(Paragraph("Orris Medical Reference  |  2026", cover_byline))
    story.append(PageBreak())

    # ═══════════════════════════════════════════════════════
    # CHAPTER 1 – ECG Basics & Systematic Approach
    # ═══════════════════════════════════════════════════════
    story.append(chapter_header("Chapter 1: ECG Basics & Systematic Approach", NAVY))
    story.append(sp(3))

    story.append(section_box("What is an ECG?", LIGHT_BLUE, NAVY))
    story.append(sp(2))
    story.append(Paragraph(
        "An electrocardiogram (ECG/EKG) records the electrical activity of the heart "
        "over time via electrodes placed on the skin. A standard 12-lead ECG captures "
        "electrical vectors from 12 different angles, providing information about rhythm, "
        "conduction, ischemia, hypertrophy, and metabolic abnormalities.", BODY_STYLE))
    story.append(sp(3))

    story.append(section_box("ECG Paper & Measurements", LIGHT_TEAL, TEAL))
    story.append(sp(2))

    measurements = [
        ["Parameter", "Small Box", "Large Box", "Standard Value"],
        ["Time (horizontal)", "0.04 sec", "0.20 sec", "Paper speed: 25 mm/s"],
        ["Voltage (vertical)", "0.1 mV", "0.5 mV", "Calibration: 1 mV = 10 mm"],
        ["PR Interval", "—", "—", "0.12 – 0.20 sec (3–5 small boxes)"],
        ["QRS Duration", "—", "—", "< 0.12 sec (< 3 small boxes)"],
        ["QT Interval", "—", "—", "< 0.44 sec (corrected QTc)"],
        ["P Wave", "—", "—", "< 0.12 sec, < 2.5 mm height"],
    ]
    story.append(make_table(
        measurements[0], measurements[1:],
        [42*mm, 28*mm, 28*mm, 72*mm], TEAL))
    story.append(sp(3))

    story.append(section_box("12-Lead ECG: Lead Groups & Views", LIGHT_BLUE, NAVY))
    story.append(sp(2))

    lead_data = [
        ["Lead Group", "Leads", "Heart Region Viewed"],
        ["Inferior", "II, III, aVF", "Inferior wall (RCA territory)"],
        ["Lateral", "I, aVL, V5, V6", "Lateral wall (LCx territory)"],
        ["Anterior (Septal)", "V1, V2", "Interventricular septum"],
        ["Anterior (Anterior)", "V3, V4", "Anterior wall (LAD territory)"],
        ["Right-sided", "V1, V3R–V6R", "Right ventricle"],
        ["Posterior", "V7–V9 (or reciprocal V1–V3)", "Posterior wall"],
        ["Augmented Limb", "aVR", "Cavity / global ischemia detector"],
    ]
    story.append(make_table(lead_data[0], lead_data[1:], [32*mm, 42*mm, 96*mm], NAVY))
    story.append(sp(3))

    story.append(section_box("The 7-Step Systematic Approach", LIGHT_ORANGE, ORANGE))
    story.append(sp(2))

    steps = [
        ("<b>Step 1 – Rate:</b>", "Count R–R intervals. 300 ÷ number of large boxes between R waves. Normal: 60–100 bpm."),
        ("<b>Step 2 – Rhythm:</b>", "Regular or irregular? P before every QRS? QRS after every P?"),
        ("<b>Step 3 – P Wave:</b>", "Present, morphology, axis (upright in I & II = sinus). Duration & amplitude."),
        ("<b>Step 4 – PR Interval:</b>", "0.12–0.20 s. Short = WPW or junctional. Long = 1st degree block."),
        ("<b>Step 5 – QRS Complex:</b>", "Duration < 0.12 s. Check axis, bundle branch blocks, delta waves."),
        ("<b>Step 6 – ST Segment & T Wave:</b>", "Elevation or depression? T wave inversion, peaked, or biphasic?"),
        ("<b>Step 7 – QT Interval:</b>", "Correct with Bazett formula: QTc = QT / √RR. Normal QTc < 440 ms (men) / < 460 ms (women)."),
    ]
    for label, desc in steps:
        row_tbl = Table([[Paragraph(label, BOLD_BODY), Paragraph(desc, BODY_STYLE)]],
                        colWidths=[40*mm, 128*mm])
        row_tbl.setStyle(TableStyle([
            ("VALIGN", (0,0), (-1,-1), "TOP"),
            ("TOPPADDING", (0,0), (-1,-1), 3),
            ("BOTTOMPADDING", (0,0), (-1,-1), 3),
            ("LEFTPADDING", (0,0), (-1,-1), 4),
        ]))
        story.append(row_tbl)
    story.append(sp(2))
    story.append(info_box(
        "⚡  REMEMBER: Always check: rate · rhythm · P wave · PR · QRS · ST-T · QTc",
        YELLOW_BG, ORANGE))
    story.append(PageBreak())

    # ═══════════════════════════════════════════════════════
    # CHAPTER 2 – Normal ECG
    # ═══════════════════════════════════════════════════════
    story.append(chapter_header("Chapter 2: Normal ECG & Key Waveforms", TEAL))
    story.append(sp(3))

    story.append(section_box("Normal Sinus Rhythm Criteria", LIGHT_TEAL, TEAL))
    story.append(sp(2))
    nsr = [
        "Rate 60–100 bpm",
        "Regular rhythm (R–R intervals vary < 10%)",
        "Upright P wave in leads I, II, aVF",
        "Inverted P wave in aVR",
        "Constant PR interval (0.12–0.20 s)",
        "Every P followed by a QRS; every QRS preceded by a P",
        "QRS duration < 0.12 s (narrow complex)",
        "Normal axis: –30° to +90°",
    ]
    for b in nsr:
        story.append(bullet(b))
    story.append(sp(3))

    story.append(section_box("Normal Waveform Characteristics", LIGHT_BLUE, NAVY))
    story.append(sp(2))
    wave_data = [
        ["Wave / Segment", "Normal Features", "Clinical Significance"],
        ["P Wave", "< 0.12 s, < 2.5 mm, biphasic in V1", "Atrial depolarisation"],
        ["PR Segment", "Isoelectric, 0.12–0.20 s", "AV node conduction delay"],
        ["Q Wave", "< 0.04 s, < 25% of R height", "Septal or pathological (wide/deep)"],
        ["R Wave", "Progressive increase V1→V5", "Ventricular depolarisation"],
        ["S Wave", "Decreases V4→V6", "Late ventricular activation"],
        ["ST Segment", "Isoelectric (±0.5 mm in limb; ±1 mm in precordial)", "Repolarisation; elevation/depression = ischaemia"],
        ["T Wave", "Upright except aVR, V1 (±III); ≥ 1/8 but ≤ 2/3 of R", "Ventricular repolarisation"],
        ["U Wave", "Small positive deflection after T (best seen V2–V3)", "Often hypokalaemia; inverted = ischaemia"],
        ["QTc", "< 440 ms ♂, < 460 ms ♀", "Prolonged = risk of Torsades de Pointes"],
    ]
    story.append(make_table(wave_data[0], wave_data[1:], [38*mm, 58*mm, 74*mm], NAVY))
    story.append(sp(3))

    story.append(section_box("Axis Interpretation", LIGHT_PURPLE, PURPLE))
    story.append(sp(2))
    axis_data = [
        ["Axis", "Degrees", "Leads I & aVF", "Common Causes"],
        ["Normal", "−30° to +90°", "Both positive", "Normal"],
        ["Left Axis Deviation (LAD)", "−30° to −90°", "I +ve, aVF –ve", "LBBB, LAHB, inferior MI, LVH"],
        ["Right Axis Deviation (RAD)", "+90° to +180°", "I –ve, aVF +ve", "RBBB, RVH, lateral MI, PE"],
        ["Extreme / NW", "−90° to ±180°", "Both negative", "VT, severe emphysema, dextrocardia"],
    ]
    story.append(make_table(axis_data[0], axis_data[1:], [38*mm, 24*mm, 36*mm, 72*mm], PURPLE))
    story.append(PageBreak())

    # ═══════════════════════════════════════════════════════
    # CHAPTER 3 – Arrhythmias
    # ═══════════════════════════════════════════════════════
    story.append(chapter_header("Chapter 3: Arrhythmias", RED))
    story.append(sp(3))

    # ── Sinus arrhythmias
    story.append(section_box("3.1  Sinus Arrhythmias", LIGHT_BLUE, NAVY))
    story.append(sp(2))
    sinus_data = [
        ["Arrhythmia", "Rate", "Key ECG Feature", "Clinical Note"],
        ["Sinus Bradycardia", "< 60 bpm", "Normal P–QRS; slow rate", "Athletes, hypothyroidism, beta-blockers, vasovagal"],
        ["Sinus Tachycardia", "> 100 bpm", "Normal P–QRS; fast rate", "Pain, fever, PE, heart failure, anaemia, drugs"],
        ["Sinus Arrhythmia", "60–100 bpm", "Irregular R–R, varies with breathing", "Normal variant; prominent in young/athletes"],
        ["Sick Sinus Syndrome", "Variable", "Brady-tachy alternation, pauses > 2 s, SA block", "Requires pacemaker if symptomatic"],
    ]
    story.append(make_table(sinus_data[0], sinus_data[1:], [38*mm, 20*mm, 58*mm, 54*mm], RED))
    story.append(sp(3))

    # ── Supraventricular
    story.append(section_box("3.2  Supraventricular Arrhythmias", LIGHT_TEAL, TEAL))
    story.append(sp(2))
    sva_data = [
        ["Arrhythmia", "Rate", "Key ECG Features", "Notes"],
        ["PAC (Premature Atrial Complex)", "—", "Early P' wave, abnormal morphology, compensatory pause incomplete", "Benign; can trigger SVT/AF"],
        ["AVNRT (SVT)", "150–250 bpm", "Regular narrow QRS; P buried in / just after QRS (pseudo-r' in V1, pseudo-s in II)", "Most common paroxysmal SVT; vagal manoeuvres / adenosine"],
        ["AVRT (WPW-related SVT)", "150–300 bpm", "Narrow QRS (orthodromic) or wide (antidromic); pre-excitation during sinus = delta wave, short PR", "Avoid AV nodal agents in pre-excited AF"],
        ["Atrial Flutter", "Atrial 300 bpm; ventricular 150 bpm (2:1)", "Sawtooth flutter waves in II, III, aVF; regular ventricular response", "Ablation highly effective; anticoagulate"],
        ["Atrial Fibrillation (AF)", "Atrial 350–600 bpm; ventricular variable", "Irregularly irregular rhythm; absent P waves; fibrillatory baseline", "Most common sustained arrhythmia; stroke risk → CHA₂DS₂-VASc"],
        ["Multifocal AT (MAT)", "100–200 bpm", "Irregular; ≥ 3 distinct P wave morphologies; variable PR", "COPD, electrolyte disorders, elderly"],
        ["Junctional Rhythm", "40–60 bpm", "Absent or inverted P (before/during/after QRS); narrow QRS", "AV nodal escape; seen in inferior MI, digoxin toxicity"],
    ]
    story.append(make_table(sva_data[0], sva_data[1:], [40*mm, 22*mm, 58*mm, 50*mm], TEAL))
    story.append(sp(3))

    # ── Ventricular arrhythmias
    story.append(section_box("3.3  Ventricular Arrhythmias", LIGHT_ORANGE, ORANGE))
    story.append(sp(2))
    va_data = [
        ["Arrhythmia", "Rate", "Key ECG Features", "Management"],
        ["PVC (Premature Ventricular Complex)", "—", "Wide bizarre QRS ≥ 0.12 s; full compensatory pause; no P before", "Treat underlying cause; frequent PVCs (> 10,000/day) can cause CMP"],
        ["Accelerated Idioventricular Rhythm (AIVR)", "40–120 bpm", "Wide QRS, regular, no P preceding; often post-MI reperfusion", "Usually benign & self-limiting"],
        ["Ventricular Tachycardia (VT)", "> 100 bpm (usually 130–250)", "Wide complex tachycardia (QRS ≥ 0.12 s); AV dissociation, fusion / capture beats", "If pulse: amiodarone/cardioversion. Pulseless: defib"],
        ["Ventricular Fibrillation (VF)", "Chaotic", "Chaotic undulations; no identifiable QRS; no pulse", "Immediate defibrillation + CPR (ACLS)"],
        ["Torsades de Pointes (TdP)", "200–250 bpm", "Polymorphic VT; QRS twists around isoelectric axis; preceded by long QTc", "Magnesium IV; remove QT-prolonging drugs; overdrive pacing"],
        ["Brugada Syndrome", "—", "Coved-type ST elevation V1–V2; RBBB pattern; can trigger sudden VF", "ICD implantation; avoid sodium channel blockers"],
    ]
    story.append(make_table(va_data[0], va_data[1:], [42*mm, 22*mm, 60*mm, 46*mm], ORANGE))
    story.append(sp(2))
    story.append(info_box(
        "⚠  VT vs SVT with aberrancy: Brugada criteria, Vereckei algorithm. "
        "Key clues for VT: AV dissociation, fusion beats, concordance, extreme axis, QRS ≥ 0.16 s.",
        colors.HexColor("#FDEDEC"), DARK_RED))
    story.append(PageBreak())

    # ═══════════════════════════════════════════════════════
    # CHAPTER 4 – Conduction Blocks
    # ═══════════════════════════════════════════════════════
    story.append(chapter_header("Chapter 4: Conduction Blocks", PURPLE))
    story.append(sp(3))

    story.append(section_box("4.1  AV Blocks", LIGHT_PURPLE, PURPLE))
    story.append(sp(2))
    av_data = [
        ["Block", "PR Interval", "QRS Dropped?", "Rhythm", "Clinical Significance"],
        ["1st Degree AV Block", "> 0.20 s; constant", "No", "Regular", "Often benign; monitor; can be caused by vagal tone, inferior MI, drugs"],
        ["2nd Degree Mobitz I (Wenckebach)", "Progressive lengthening", "Yes – periodically", "Irregular grouped beating", "AV node dysfunction; usually benign; inferior MI; vagal"],
        ["2nd Degree Mobitz II", "Constant (normal or long)", "Yes – suddenly, without warning", "Regular except for dropped beats", "HIS/Purkinje disease; often progresses to complete heart block → pacemaker"],
        ["2:1 AV Block", "Constant", "Every alternate P dropped", "Regular at half atrial rate", "Cannot classify as Mobitz I or II without ≥ 3 P waves together; needs EP study"],
        ["3rd Degree (Complete) AV Block", "No relationship (AV dissociation)", "QRS unrelated to P waves; escape rhythm", "Atrial regular; ventricular regular but independent", "Emergency: junctional escape (narrow, 40–60) or ventricular escape (wide, < 40); requires pacing"],
    ]
    story.append(make_table(av_data[0], av_data[1:], [38*mm, 30*mm, 26*mm, 26*mm, 50*mm], PURPLE))
    story.append(sp(3))

    story.append(section_box("4.2  Bundle Branch Blocks", LIGHT_BLUE, NAVY))
    story.append(sp(2))

    story.append(Paragraph("<b>Right Bundle Branch Block (RBBB)</b>", SUBSECTION_STYLE))
    for b in [
        "QRS ≥ 0.12 s (complete RBBB) or 0.10–0.12 s (incomplete RBBB)",
        "rSR' ('M' pattern / rabbit ears) in V1–V2",
        "Wide, slurred S wave in I, aVL, V5–V6",
        "Secondary ST-T changes (ST depression + T inversion in V1–V3)",
        "Causes: normal variant, PE, RVH, ASD, anterior MI, post-cardiac surgery",
    ]:
        story.append(bullet(b))
    story.append(sp(2))

    story.append(Paragraph("<b>Left Bundle Branch Block (LBBB)</b>", SUBSECTION_STYLE))
    for b in [
        "QRS ≥ 0.12 s",
        "Broad, notched R wave ('M' shape) in I, aVL, V5–V6 (no septal Q waves)",
        "rS or QS pattern in V1–V3",
        "Discordant ST-T changes (opposite to main QRS deflection)",
        "New LBBB + chest pain = treat as STEMI equivalent (Sgarbossa criteria)",
        "Causes: IHD, dilated CMP, hypertension, aortic valve disease",
    ]:
        story.append(bullet(b))
    story.append(sp(2))

    story.append(Paragraph("<b>Fascicular Blocks (Hemiblocks)</b>", SUBSECTION_STYLE))
    fascicular_data = [
        ["Block", "Axis", "Lead I", "Lead II/III", "Notes"],
        ["Left Anterior Hemiblock (LAHB)", "LAD (−30° to −90°)", "+ve (qR)", "rS", "Most common; narrow QRS; no right axis shift"],
        ["Left Posterior Hemiblock (LPHB)", "RAD (+90° to +120°)", "rS", "+ve (qR)", "Rare; must exclude other RAD causes"],
        ["Bifascicular Block", "LAD", "RBBB + LAHB pattern", "—", "RBBB + LAHB; risk of complete block"],
        ["Trifascicular Block", "Variable", "1st-degree block + bifascicular", "—", "High risk of complete heart block; consider pacing"],
    ]
    story.append(make_table(fascicular_data[0], fascicular_data[1:], [40*mm, 24*mm, 24*mm, 24*mm, 58*mm], NAVY))
    story.append(PageBreak())

    # ═══════════════════════════════════════════════════════
    # CHAPTER 5 – Ischaemia & MI
    # ═══════════════════════════════════════════════════════
    story.append(chapter_header("Chapter 5: Ischaemia, Injury & Myocardial Infarction", DARK_RED))
    story.append(sp(3))

    story.append(section_box("5.1  Spectrum of Ischaemic ECG Changes", LIGHT_ORANGE, ORANGE))
    story.append(sp(2))
    isch_data = [
        ["Stage", "ECG Findings", "Pathophysiology"],
        ["Hyper-Acute (minutes)", "Tall, peaked 'hyperacute' T waves; ST straightening", "Acute transmural ischaemia; earliest sign"],
        ["Acute Injury (minutes–hours)", "ST elevation ≥ 1 mm in ≥ 2 contiguous leads (≥ 2 mm in V1–V4)", "Transmural injury current; STEMI criteria"],
        ["Established Infarction (hours–days)", "Pathological Q waves (≥ 0.04 s, ≥ 25% of R); ST normalises", "Myocyte necrosis; Q wave = dead tissue"],
        ["Chronic / Resolved (weeks–months)", "Persistent Q waves; T wave normalisation (may invert)", "Scar tissue; Q waves often permanent"],
        ["Subendocardial Ischaemia (NSTEMI/UA)", "Horizontal/downsloping ST depression ≥ 0.5 mm; T inversion", "Partial thickness ischaemia; no Q waves typically"],
    ]
    story.append(make_table(isch_data[0], isch_data[1:], [40*mm, 72*mm, 58*mm], ORANGE))
    story.append(sp(3))

    story.append(section_box("5.2  MI Localisation by Territory", LIGHT_BLUE, NAVY))
    story.append(sp(2))
    mi_data = [
        ["Territory", "Artery (Usual)", "Leads with ST Changes", "Reciprocal Changes"],
        ["Inferior MI", "RCA (85%) / LCx (15%)", "II, III, aVF", "I, aVL"],
        ["Anterior MI", "LAD (proximal)", "V1–V4 (or V1–V6)", "II, III, aVF (sometimes)"],
        ["Anteroseptal MI", "LAD (septal branches)", "V1–V3", "None specific"],
        ["Anterolateral MI", "LAD or LCx", "V1–V6, I, aVL", "II, III, aVF"],
        ["Lateral MI", "LCx / diagonal branch", "I, aVL, V5–V6", "V1–V3, II, III, aVF"],
        ["Posterior MI", "RCA / LCx", "V1–V3 ST depression; tall R wave", "ST elevation V7–V9 (posterior leads)"],
        ["Right Ventricular MI", "Proximal RCA", "V1 ST elevation; ST elevation V3R–V4R", "Usually with inferior MI (II, III, aVF)"],
        ["High Lateral / Apical", "Diagonal / OM branch", "I, aVL only (or none)", "II, III"],
    ]
    story.append(make_table(mi_data[0], mi_data[1:], [36*mm, 36*mm, 50*mm, 48*mm], DARK_RED))
    story.append(sp(3))

    story.append(section_box("5.3  Sgarbossa Criteria (MI in LBBB)", LIGHT_ORANGE, ORANGE))
    story.append(sp(2))
    sgarbossa = [
        ("<b>Criterion 1 (5 pts):</b>", "ST elevation ≥ 1 mm concordant with QRS direction"),
        ("<b>Criterion 2 (3 pts):</b>", "ST depression ≥ 1 mm in V1, V2, or V3 (concordant negative)"),
        ("<b>Criterion 3 (2 pts):</b>", "ST elevation ≥ 5 mm discordant with QRS direction"),
    ]
    for label, desc in sgarbossa:
        row = Table([[Paragraph(label, BOLD_BODY), Paragraph(desc, BODY_STYLE)]],
                    colWidths=[40*mm, 128*mm])
        row.setStyle(TableStyle([
            ("VALIGN", (0,0), (-1,-1), "TOP"),
            ("TOPPADDING", (0,0), (-1,-1), 3),
            ("LEFTPADDING", (0,0), (-1,-1), 4),
        ]))
        story.append(row)
    story.append(sp(1))
    story.append(info_box("Score ≥ 3 = high specificity for AMI. Modified Sgarbossa: use proportional criterion (ST/S ratio ≥ 0.25) instead of absolute 5 mm rule.", YELLOW_BG, ORANGE))
    story.append(PageBreak())

    # ═══════════════════════════════════════════════════════
    # CHAPTER 6 – Hypertrophy & Enlargement
    # ═══════════════════════════════════════════════════════
    story.append(chapter_header("Chapter 6: Chamber Hypertrophy & Enlargement", TEAL))
    story.append(sp(3))

    story.append(section_box("6.1  Ventricular Hypertrophy", LIGHT_TEAL, TEAL))
    story.append(sp(2))
    vh_data = [
        ["Criteria", "LVH", "RVH"],
        ["Voltage (main)", "Sokolow-Lyon: S(V1) + R(V5/V6) ≥ 35 mm\nCornell: R(aVL) ≥ 11 mm\nR(aVL) + S(V3) > 28 mm (M) / > 20 mm (F)", "R > S in V1; R in V1 ≥ 7 mm\nS in V5/V6 > 7 mm\nR:S ratio in V1 ≥ 1"],
        ["Axis", "LAD or normal", "RAD > +90°"],
        ["ST-T Changes", "Strain pattern: ST depression + T inversion in I, aVL, V5–V6", "Strain: ST depression + T inversion in V1–V4"],
        ["P Wave", "Often normal; may have P mitrale if raised LVEDP", "May show P pulmonale (tall P ≥ 2.5 mm)"],
        ["Causes", "HTN, aortic stenosis, HCM, AR", "Cor pulmonale, PE, pulmonary HTN, PS"],
    ]
    tbl = Table(
        [[Paragraph(vh_data[0][0], TABLE_HEADER), Paragraph(vh_data[0][1], TABLE_HEADER), Paragraph(vh_data[0][2], TABLE_HEADER)]] +
        [[Paragraph(r[0], TABLE_CELL), Paragraph(r[1], TABLE_CELL), Paragraph(r[2], TABLE_CELL)] for r in vh_data[1:]],
        colWidths=[30*mm, 72*mm, 68*mm]
    )
    tbl.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,0), TEAL),
        ("ROWBACKGROUNDS", (0,1), (-1,-1), [WHITE, LIGHT_TEAL]),
        ("GRID", (0,0), (-1,-1), 0.4, GRAY_MID),
        ("TOPPADDING", (0,0), (-1,-1), 5), ("BOTTOMPADDING", (0,0), (-1,-1), 5),
        ("LEFTPADDING", (0,0), (-1,-1), 6), ("RIGHTPADDING", (0,0), (-1,-1), 6),
        ("VALIGN", (0,0), (-1,-1), "TOP"),
    ]))
    story.append(tbl)
    story.append(sp(3))

    story.append(section_box("6.2  Atrial Enlargement", LIGHT_BLUE, NAVY))
    story.append(sp(2))
    atrial_data = [
        ["Feature", "Left Atrial Enlargement (LAE)", "Right Atrial Enlargement (RAE)"],
        ["P Wave Duration", "> 0.12 s (P mitrale)", "Normal or short"],
        ["P Wave Height", "Normal (or terminal negative portion in V1 > 1 mm × 1 mm box)", "≥ 2.5 mm in II, III, or aVF (P pulmonale)"],
        ["P Wave Morphology", "Bifid/notched P in II; biphasic in V1 with broad negative terminal", "Peaked, tall, narrow P"],
        ["Common Causes", "Mitral stenosis/regurgitation, HTN, LHF", "COPD, pulmonary HTN, tricuspid disease, RHF"],
    ]
    story.append(make_table(atrial_data[0], atrial_data[1:], [34*mm, 68*mm, 68*mm], NAVY))
    story.append(PageBreak())

    # ═══════════════════════════════════════════════════════
    # CHAPTER 7 – Electrolyte & Metabolic Disorders
    # ═══════════════════════════════════════════════════════
    story.append(chapter_header("Chapter 7: Electrolyte & Metabolic Disorders", colors.HexColor("#1A5276")))
    story.append(sp(3))

    story.append(section_box("7.1  Potassium Disorders", LIGHT_BLUE, NAVY))
    story.append(sp(2))
    k_data = [
        ["K+ Level", "ECG Changes", "Clinical Sequence"],
        ["Hypokalaemia\n< 3.5 mEq/L", "U wave prominence (V2–V3); T–U fusion; T wave flattening; QTU prolongation; ST depression; PVCs; TdP", "K 3–3.5: U waves → K 2.5–3: flat T, U > T → K < 2.5: T/U fusion, ST depression → K < 2: VF risk"],
        ["Hyperkalaemia\n> 5.5 mEq/L", "Peaked narrow T waves → PR prolongation → P wave flattening/disappearance → QRS widening → sine wave pattern → VF/asystole", "K 5.5–6.5: tall T → K 6.5–7.5: PR long, P flat → K > 7.5: wide QRS, sine wave → K > 9: cardiac arrest"],
    ]
    tbl_k = Table(
        [[Paragraph(k_data[0][0], TABLE_HEADER), Paragraph(k_data[0][1], TABLE_HEADER), Paragraph(k_data[0][2], TABLE_HEADER)]] +
        [[Paragraph(r[0], TABLE_CELL), Paragraph(r[1], TABLE_CELL), Paragraph(r[2], TABLE_CELL)] for r in k_data[1:]],
        colWidths=[30*mm, 72*mm, 68*mm]
    )
    tbl_k.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,0), NAVY),
        ("ROWBACKGROUNDS", (0,1), (-1,-1), [WHITE, LIGHT_BLUE]),
        ("GRID", (0,0), (-1,-1), 0.4, GRAY_MID),
        ("TOPPADDING", (0,0), (-1,-1), 6), ("BOTTOMPADDING", (0,0), (-1,-1), 6),
        ("LEFTPADDING", (0,0), (-1,-1), 6), ("RIGHTPADDING", (0,0), (-1,-1), 6),
        ("VALIGN", (0,0), (-1,-1), "TOP"),
    ]))
    story.append(tbl_k)
    story.append(sp(3))

    story.append(section_box("7.2  Other Electrolyte & Metabolic Disorders", LIGHT_TEAL, TEAL))
    story.append(sp(2))
    met_data = [
        ["Disorder", "ECG Findings", "Memory Aid"],
        ["Hypercalcaemia", "Short QT interval; short ST segment; prolonged PR; Osborn wave (rarely)", "Ca UP → QT DOWN"],
        ["Hypocalcaemia", "Prolonged QT (prolonged ST segment); T wave normal or inverted", "Ca DOWN → QT UP"],
        ["Hypomagnesaemia", "Prolonged QTc; T wave changes; TdP risk; similar to hypokalaemia", "Often coexists with hypokalaemia"],
        ["Hypothyroidism", "Sinus bradycardia; low voltage; prolonged QTc; T wave flattening/inversion; pericardial effusion pattern", "Think slow + low"],
        ["Hyperthyroidism", "Sinus tachycardia; AF; shortened QTc; high voltage", "Think fast + irregular"],
        ["Hypothermia", "Sinus bradycardia; Osborn (J) wave at QRS/ST junction; AF; prolonged intervals; VF risk", "Osborn waves pathognomonic"],
        ["Digoxin Effect", "Sagging ('reverse tick' or 'Salvador Dali moustache') ST depression; T wave inversion; shortened QT; PR prolongation", "ST scooping = digoxin effect (not toxicity)"],
        ["Digoxin Toxicity", "Any arrhythmia: PAT with block, regularised AF, VT/VF, junctional rhythms, PVCs (bigeminy)", "Classic: PAT with 2:1 block"],
    ]
    story.append(make_table(met_data[0], met_data[1:], [36*mm, 80*mm, 54*mm], TEAL))
    story.append(PageBreak())

    # ═══════════════════════════════════════════════════════
    # CHAPTER 8 – Special Conditions
    # ═══════════════════════════════════════════════════════
    story.append(chapter_header("Chapter 8: Special & Specific Conditions", colors.HexColor("#117A65")))
    story.append(sp(3))

    story.append(section_box("8.1  Pericarditis", LIGHT_TEAL, TEAL))
    story.append(sp(2))
    for b in [
        "<b>Saddle-shaped (concave up) diffuse ST elevation</b> in most leads except aVR and V1 (which show ST depression)",
        "<b>PR depression</b> – most specific finding; best seen in II and aVL",
        "<b>No reciprocal changes</b> (unlike MI) – a key differentiator",
        "<b>T wave inversion</b> occurs later (after ST normalises; Stage III)",
        "<b>Stages:</b> I (ST elevation, PR depression) → II (normalisation) → III (T inversion) → IV (normalisation)",
        "<b>Spodick's sign:</b> downsloping TP segment (best in II); sensitive early finding",
    ]:
        story.append(bullet(b))
    story.append(sp(3))

    story.append(section_box("8.2  Pulmonary Embolism (PE)", LIGHT_ORANGE, ORANGE))
    story.append(sp(2))
    for b in [
        "<b>Sinus tachycardia</b> – most common ECG finding in PE (present in ~40%)",
        "<b>S1Q3T3 pattern:</b> S wave in I + Q wave in III + T inversion in III (present in ~20% – not sensitive or specific alone)",
        "<b>Right heart strain:</b> new RBBB (complete or incomplete), RAD, right axis shift",
        "<b>T wave inversions V1–V4</b> – suggests RV strain; can mimic anterior ischaemia",
        "<b>AF or atrial flutter</b> may precipitate",
        "<b>Low voltage / sinus tachycardia alone</b> – should prompt CT-PA if clinically suspicious",
    ]:
        story.append(bullet(b))
    story.append(sp(3))

    story.append(section_box("8.3  Wolff-Parkinson-White (WPW) Syndrome", LIGHT_PURPLE, PURPLE))
    story.append(sp(2))
    for b in [
        "<b>Short PR interval</b> (< 0.12 s) – accessory pathway bypasses AV node",
        "<b>Delta wave</b> – slurred upstroke of QRS; initial slow conduction via accessory pathway",
        "<b>Wide QRS</b> (> 0.12 s) due to delta wave",
        "<b>Secondary ST-T changes</b> (discordant to QRS)",
        "<b>Risk:</b> AF with rapid ventricular response → VF if accessory pathway has short refractory period",
        "<b>AVOID:</b> Adenosine, digoxin, verapamil, beta-blockers in pre-excited AF (can accelerate conduction)",
    ]:
        story.append(bullet(b))
    story.append(sp(3))

    story.append(section_box("8.4  Long QT Syndromes", LIGHT_ORANGE, ORANGE))
    story.append(sp(2))
    lqt_data = [
        ["Type", "Gene", "Trigger", "T Wave Morphology"],
        ["LQT1 (KCNQ1)", "IKs loss of function", "Exercise / emotion", "Broad-based T wave"],
        ["LQT2 (KCNH2 / hERG)", "IKr loss of function", "Sudden sound / auditory startle", "Notched / bifid T wave"],
        ["LQT3 (SCN5A)", "INa gain of function", "Sleep / rest / bradycardia", "Long flat ST, late T wave"],
        ["Acquired (drugs, electrolytes)", "Multiple channels", "Drug initiation, hypokalaemia, hypomagnesaemia", "Variable QT prolongation"],
    ]
    story.append(make_table(lqt_data[0], lqt_data[1:], [38*mm, 36*mm, 44*mm, 52*mm], ORANGE))
    story.append(sp(2))
    story.append(info_box(
        "Common QT-prolonging drugs: antiarrhythmics (sotalol, amiodarone, quinidine), "
        "antibiotics (azithromycin, fluoroquinolones), antipsychotics (haloperidol, quetiapine), "
        "antidepressants (tricyclics, citalopram), antiemetics (ondansetron, metoclopramide).",
        YELLOW_BG, ORANGE))
    story.append(sp(3))

    story.append(section_box("8.5  Early Repolarisation vs. STEMI", LIGHT_GREEN, GREEN))
    story.append(sp(2))
    er_data = [
        ["Feature", "Early Repolarisation", "STEMI"],
        ["ST Morphology", "Concave (smiley face) upward", "Convex (frowning face) or flat upward"],
        ["Distribution", "Inferior and lateral leads; often widespread", "Localised to specific territory"],
        ["Reciprocal Changes", "Absent", "Present (key differentiator)"],
        ["J-Point Notching", "Characteristic notch or slur at J-point", "Usually absent"],
        ["Evolution", "Stable; no dynamic change", "Dynamic: evolving over time"],
        ["ST:T ratio (V6)", "< 0.25", "≥ 0.25 suggests STEMI/pericarditis"],
        ["Clinical Context", "Young, athletic, asymptomatic (usually)", "Chest pain, troponin rise, symptoms"],
    ]
    story.append(make_table(er_data[0], er_data[1:], [40*mm, 65*mm, 65*mm], GREEN))
    story.append(PageBreak())

    # ═══════════════════════════════════════════════════════
    # CHAPTER 9 – Quick Reference & Differentials
    # ═══════════════════════════════════════════════════════
    story.append(chapter_header("Chapter 9: Quick Reference & Clinical Differentials", NAVY))
    story.append(sp(3))

    story.append(section_box("ST Elevation Differential Diagnosis (STEMI Mimics)", LIGHT_ORANGE, ORANGE))
    story.append(sp(2))
    stemi_dd = [
        ["Cause", "Distinguishing ECG Feature", "Clinical Clue"],
        ["STEMI", "Convex ST elevation, reciprocal changes, evolution, Q waves", "Chest pain, troponin +ve"],
        ["Pericarditis", "Diffuse concave ST elevation, PR depression, no reciprocals", "Pleuritic pain, friction rub, viral prodrome"],
        ["Early Repolarisation", "Concave ST, J-point notch, stable, young", "Asymptomatic, athlete"],
        ["LBBB (new)", "Sgarbossa criteria; convex ST in concordant leads", "May need primary PCI if new LBBB + chest pain"],
        ["Brugada Pattern", "Coved ST in V1–V2 only, RBBB morphology", "Family history of sudden death, fever precipitates"],
        ["LVH Strain", "V5–V6 ST elevation possible; high voltage", "Hypertension, no acute symptoms"],
        ["Vasospasm / Prinzmetal", "Transient ST elevation, resolves with nitrates", "Occurs at rest, often at night"],
        ["Hyperkalaemia", "Wide QRS, peaked T, sine wave; may mimic STEMI", "Renal failure, peaked T waves universally"],
        ["Takotsubo (Stress) CMP", "Initial: ST elevation V1–V4; later: diffuse T inversion, QTc prolongation", "Emotional stress, post-menopausal women, apical ballooning"],
    ]
    story.append(make_table(stemi_dd[0], stemi_dd[1:], [36*mm, 66*mm, 68*mm], ORANGE))
    story.append(sp(3))

    story.append(section_box("Wide Complex Tachycardia (WCT) Differential", LIGHT_PURPLE, PURPLE))
    story.append(sp(2))
    wct_data = [
        ["Criterion", "Favours VT", "Favours SVT with Aberrancy"],
        ["AV Dissociation", "Present (P waves unrelated to QRS)", "Absent"],
        ["Fusion Beats", "Present", "Absent"],
        ["Capture Beats", "Present", "Absent"],
        ["QRS Duration", "> 0.16 s", "Usually < 0.14 s"],
        ["Axis", "Extreme NW axis (−90° to ±180°)", "LAD possible (LBBB morphology)"],
        ["Onset", "Abrupt; no initiating PAC", "Often initiated by PAC; RP < PR"],
        ["V Lead Concordance", "All positive or all negative V1–V6", "Mixed"],
        ["RS Nadir to S", "> 100 ms in any V lead (Brugada sign)", "< 100 ms"],
        ["Prior ECG", "Sinus ECG different from WCT morphology", "WCT matches pre-existing BBB"],
        ["History", "Structural heart disease strongly favours VT", "No structural heart disease"],
    ]
    story.append(make_table(wct_data[0], wct_data[1:], [40*mm, 70*mm, 60*mm], PURPLE))
    story.append(sp(3))

    story.append(section_box("Common Drug Effects on ECG", LIGHT_TEAL, TEAL))
    story.append(sp(2))
    drug_data = [
        ["Drug / Class", "ECG Effects", "Key Concern"],
        ["Digoxin (therapeutic)", "Scooping ST depression ('reverse tick'); short QT; PR prolongation; T inversion", "Toxicity: any arrhythmia; PAT with block classic"],
        ["Beta-Blockers", "Sinus bradycardia; PR prolongation; AV block", "Overdose: severe bradycardia, hypotension"],
        ["Calcium Channel Blockers (non-DHP)", "Sinus bradycardia; PR prolongation; AV block (verapamil > diltiazem)", "Overdose: fatal bradycardia; may cause AF"],
        ["Tricyclic Antidepressants (TCA)", "Wide QRS; prolonged QTc; right axis; deep S in I; tall R in aVR", "R:S ratio in aVR > 0.7 predicts seizure/arrhythmia"],
        ["Amiodarone", "Sinus bradycardia; prolonged PR, QRS, QTc; T wave changes; corneal microdeposits", "Pro-arrhythmic despite anti-arrhythmic classification"],
        ["Adenosine", "Transient AV block; brief asystole (1–3 s); sinus bradycardia", "Diagnostic/therapeutic in SVT; CI in WPW pre-excited AF"],
        ["Cocaine", "Sinus tachycardia; STEMI (coronary spasm); prolonged QTc; VT/VF", "Cocaine + beta-blocker = unopposed alpha → dangerous"],
    ]
    story.append(make_table(drug_data[0], drug_data[1:], [38*mm, 72*mm, 60*mm], TEAL))
    story.append(PageBreak())

    # ═══════════════════════════════════════════════════════
    # CHAPTER 10 – Summary Cheatsheet
    # ═══════════════════════════════════════════════════════
    story.append(chapter_header("Chapter 10: Rapid ECG Cheatsheet", RED))
    story.append(sp(3))

    story.append(section_box("One-Line Summaries – High-Yield for Exams & Clinics", LIGHT_BLUE, NAVY))
    story.append(sp(2))

    cheat_data = [
        ["Finding", "Diagnosis / Condition"],
        ["Irregularly irregular + no P waves", "Atrial Fibrillation"],
        ["Sawtooth waves at 300 bpm + regular ventricular response", "Atrial Flutter (2:1 block → 150 bpm)"],
        ["P buried in QRS or pseudo-r' V1 + pseudo-s II (narrow, fast)", "AVNRT (commonest SVT)"],
        ["Short PR + delta wave + wide QRS", "WPW (pre-excitation)"],
        ["Wide QRS > 0.12 s + rSR' in V1 + wide S in I, V6", "Right Bundle Branch Block (RBBB)"],
        ["Wide QRS + broad notched R in I/V6 + no septal Q waves", "Left Bundle Branch Block (LBBB)"],
        ["ST elevation + concave + PR depression + no reciprocals", "Pericarditis"],
        ["ST elevation + convex + reciprocal changes + Q waves", "STEMI"],
        ["Horizontal ST depression + T inversion (no Q waves)", "NSTEMI / Subendocardial ischaemia"],
        ["Progressive PR lengthening → dropped QRS (grouped beating)", "2nd degree AV block – Mobitz I (Wenckebach)"],
        ["Constant PR + sudden dropped QRS (no warning)", "2nd degree AV block – Mobitz II"],
        ["P waves unrelated to QRS + escape rhythm", "3rd degree (complete) AV block"],
        ["Peaked T → wide QRS → sine wave + hyperkalaemia history", "Hyperkalaemia"],
        ["Prominent U waves + flat T (U > T)", "Hypokalaemia"],
        ["Short QT interval", "Hypercalcaemia (or congenital short QT syndrome)"],
        ["Prolonged QT + polymorphic VT twisting axis", "Torsades de Pointes (Long QT)"],
        ["Coved ST elevation V1–V2 + RBBB morphology", "Brugada Syndrome"],
        ["S1Q3T3 + tachycardia + right heart strain", "Pulmonary Embolism (PE)"],
        ["Osborn (J) wave at J point + bradycardia + prolonged intervals", "Hypothermia"],
        ["Sagging ST ('reverse tick') + short QT + PR prolongation", "Digoxin Effect (therapeutic)"],
        ["Sokolow-Lyon voltage ≥ 35 mm + strain pattern", "Left Ventricular Hypertrophy (LVH)"],
        ["R > S in V1 + RAD + RV strain pattern", "Right Ventricular Hypertrophy (RVH)"],
        ["Diffuse T wave inversion + QTc prolongation + apical ballooning", "Takotsubo (Stress) Cardiomyopathy"],
        ["Delta + wide QRS + AF with rapid irregular wide QRS", "WPW + AF → risk of VF"],
        ["Wide complex tachycardia + AV dissociation + fusion beats", "Ventricular Tachycardia (VT) – proven"],
    ]
    story.append(make_table(cheat_data[0], cheat_data[1:],
                            [100*mm, 70*mm], DARK_RED, colors.HexColor("#FDEDEC")))
    story.append(sp(3))

    story.append(info_box(
        "📌  GOLDEN RULE: In any wide complex tachycardia with haemodynamic instability → "
        "treat as VT and cardiovert. Never delay treatment to achieve a diagnosis.",
        colors.HexColor("#FDEDEC"), DARK_RED))
    story.append(sp(4))

    story.append(info_box(
        "📚  Recommended Reading:\n"
        "• The ECG Made Easy – John Hampton (beginner)\n"
        "• The ECG in Practice – John Hampton (intermediate)\n"
        "• 150 ECG Problems – Hampton (case-based practice)\n"
        "• Marriott's Practical Electrocardiography (advanced)\n"
        "• LITFL ECG Library – litfl.com/ecg-library (free online, disorder-by-disorder)",
        LIGHT_TEAL, TEAL))

    # ── Final page ──
    story.append(sp(6))
    story.append(hr(NAVY, 1))
    footer_style = style("footer", fontName="Helvetica-Oblique", fontSize=8.5,
                         textColor=colors.HexColor("#555555"), alignment=TA_CENTER, leading=12)
    story.append(Paragraph(
        "This guide is intended as an educational reference only. "
        "Always correlate ECG findings with clinical history, physical examination, and other investigations. "
        "Orris Medical Reference | ECG Complete Guide | 2026",
        footer_style))

    # ── Build with page callbacks ──────────────────────────────────────────────
    doc.build(story,
              onFirstPage=cover_page,
              onLaterPages=normal_page)
    print(f"PDF created: {OUTPUT_PATH}")
    print(f"File size: {os.path.getsize(OUTPUT_PATH):,} bytes")

if __name__ == "__main__":
    build_pdf()