10 Common Heart Diseases: ECG Changes & Images

import requests
import os
from io import BytesIO
from reportlab.lib.pagesizes import A4
from reportlab.lib import colors
from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
from reportlab.lib.units import cm, mm
from reportlab.platypus import (
    SimpleDocTemplate, Paragraph, Spacer, Table, TableStyle,
    HRFlowable, KeepTogether, Image as RLImage, PageBreak
)
from reportlab.lib.enums import TA_CENTER, TA_LEFT, TA_JUSTIFY
from reportlab.platypus import Flowable
from PIL import Image as PILImage

OUTPUT = "/home/daytona/workspace/ecg-heart-diseases/10_Heart_Diseases_ECG.pdf"

# ── Download ECG images ──────────────────────────────────────────────────────
IMAGE_URLS = {
    "af":    "https://litfl.com/wp-content/uploads/2018/08/ECG-Atrial-Fibrillation-coarse-flutter-waves.jpg",
    "chb":   "https://litfl.com/wp-content/uploads/2018/08/ECG-Complete-heart-block-CHB-1024x498.jpg",
    "wellens": "https://cdn.orris.care/cdss_images/f3e984a53a0a64a9ac96e6035acfa4f3e60f0b0b4f43f8a50327252b01f9f891.png",
}

IMG_DIR = "/home/daytona/workspace/ecg-heart-diseases/images"
os.makedirs(IMG_DIR, exist_ok=True)

def download_image(key, url):
    path = os.path.join(IMG_DIR, f"{key}.jpg")
    if os.path.exists(path):
        return path
    try:
        r = requests.get(url, timeout=15, headers={"User-Agent": "Mozilla/5.0"})
        if r.status_code == 200:
            img = PILImage.open(BytesIO(r.content)).convert("RGB")
            img.save(path, "JPEG")
            print(f"  saved {key}")
            return path
    except Exception as e:
        print(f"  failed {key}: {e}")
    return None

downloaded = {}
for k, u in IMAGE_URLS.items():
    p = download_image(k, u)
    if p:
        downloaded[k] = p

# ── Styles ───────────────────────────────────────────────────────────────────
W, H = A4
MARGIN = 2*cm

styles = getSampleStyleSheet()

def S(name, **kw):
    return ParagraphStyle(name, **kw)

cover_title   = S("CoverTitle",   fontName="Helvetica-Bold", fontSize=28, textColor=colors.HexColor("#C0392B"),
                   alignment=TA_CENTER, spaceAfter=6)
cover_sub     = S("CoverSub",     fontName="Helvetica",      fontSize=14, textColor=colors.HexColor("#2C3E50"),
                   alignment=TA_CENTER, spaceAfter=4)
cover_note    = S("CoverNote",    fontName="Helvetica-Oblique", fontSize=10, textColor=colors.grey,
                   alignment=TA_CENTER, spaceAfter=2)

section_head  = S("SectionHead",  fontName="Helvetica-Bold", fontSize=16, textColor=colors.white,
                   backColor=colors.HexColor("#C0392B"), borderPad=6, spaceBefore=14, spaceAfter=6,
                   leftIndent=0, leading=20)
disease_num   = S("DiseaseNum",   fontName="Helvetica-Bold", fontSize=13, textColor=colors.HexColor("#2980B9"),
                   spaceBefore=10, spaceAfter=2)
body          = S("Body",         fontName="Helvetica",      fontSize=10, textColor=colors.HexColor("#2C3E50"),
                   leading=15, spaceAfter=4, alignment=TA_JUSTIFY)
bullet        = S("Bullet",       fontName="Helvetica",      fontSize=10, textColor=colors.HexColor("#2C3E50"),
                   leading=14, spaceAfter=2, leftIndent=16, bulletIndent=4)
caption       = S("Caption",      fontName="Helvetica-Oblique", fontSize=8, textColor=colors.grey,
                   alignment=TA_CENTER, spaceAfter=6)
footer_style  = S("Footer",       fontName="Helvetica",      fontSize=8,  textColor=colors.grey,
                   alignment=TA_CENTER)
table_head    = S("TableHead",    fontName="Helvetica-Bold", fontSize=9,  textColor=colors.white)
table_cell    = S("TableCell",    fontName="Helvetica",      fontSize=9,  textColor=colors.HexColor("#2C3E50"),
                   leading=13)

# ── Helper to add ECG image ──────────────────────────────────────────────────
def ecg_image(key, cap, max_w=14*cm):
    story = []
    if key in downloaded:
        img_path = downloaded[key]
        pil = PILImage.open(img_path)
        iw, ih = pil.size
        ratio = ih / iw
        disp_w = min(max_w, W - 2*MARGIN)
        disp_h = disp_w * ratio
        story.append(Spacer(1, 4))
        story.append(RLImage(img_path, width=disp_w, height=disp_h))
        story.append(Paragraph(cap, caption))
    return story

# ── Page callback for header/footer ─────────────────────────────────────────
def on_page(canvas, doc):
    canvas.saveState()
    # Header bar
    canvas.setFillColor(colors.HexColor("#C0392B"))
    canvas.rect(MARGIN, H - 1.2*cm, W - 2*MARGIN, 0.5*cm, fill=1, stroke=0)
    canvas.setFont("Helvetica-Bold", 8)
    canvas.setFillColor(colors.white)
    canvas.drawString(MARGIN + 4, H - 0.98*cm, "10 Common Heart Diseases with ECG Changes")
    canvas.drawRightString(W - MARGIN - 4, H - 0.98*cm, "Orris Medical Reference")
    # Footer
    canvas.setFillColor(colors.HexColor("#95A5A6"))
    canvas.setFont("Helvetica", 7)
    canvas.drawCentredString(W/2, 0.7*cm, f"Page {doc.page}  |  For educational purposes only  |  Sources: Harrison's 22E, Goldman-Cecil Medicine, LITFL ECG Library")
    canvas.restoreState()

# ── Build story ──────────────────────────────────────────────────────────────
story = []

# COVER PAGE
story.append(Spacer(1, 3*cm))
story.append(Paragraph("10 Common Heart Diseases", cover_title))
story.append(Paragraph("ECG Changes & Diagnostic Features", cover_sub))
story.append(Spacer(1, 0.5*cm))
story.append(HRFlowable(width="60%", thickness=2, color=colors.HexColor("#C0392B"), hAlign="CENTER"))
story.append(Spacer(1, 1*cm))

# ECG waveform visual placeholder
ecg_box_data = [["♥  ECG  |  Electrocardiography  |  Cardiology Reference"]]
ecg_box = Table(ecg_box_data, colWidths=[12*cm])
ecg_box.setStyle(TableStyle([
    ("BACKGROUND", (0,0), (-1,-1), colors.HexColor("#FDECEA")),
    ("TEXTCOLOR",  (0,0), (-1,-1), colors.HexColor("#C0392B")),
    ("FONTNAME",   (0,0), (-1,-1), "Helvetica-Bold"),
    ("FONTSIZE",   (0,0), (-1,-1), 13),
    ("ALIGN",      (0,0), (-1,-1), "CENTER"),
    ("TOPPADDING", (0,0), (-1,-1), 14),
    ("BOTTOMPADDING", (0,0), (-1,-1), 14),
    ("BOX",        (0,0), (-1,-1), 1.5, colors.HexColor("#C0392B")),
]))
story.append(ecg_box)
story.append(Spacer(1, 2*cm))
story.append(Paragraph("A comprehensive clinical reference covering the 10 most common cardiac conditions,<br/>their characteristic electrocardiographic findings, diagnostic criteria, and lead localisation.", body))
story.append(Spacer(1, 1.5*cm))
story.append(Paragraph("Sources: Harrison's Principles of Internal Medicine 22E (2025) · Goldman-Cecil Medicine · LITFL ECG Library · ESC Guidelines", cover_note))
story.append(Paragraph("Generated by Orris AI · June 2026", cover_note))
story.append(PageBreak())

# ── DISEASE DATA ─────────────────────────────────────────────────────────────

diseases = [
    {
        "num": "01",
        "title": "ST-Elevation Myocardial Infarction (STEMI)",
        "overview": (
            "STEMI occurs due to complete occlusion of a coronary artery causing transmural ischemia. "
            "It is a medical emergency requiring immediate reperfusion therapy (PCI within 90 minutes). "
            "The ECG evolves dynamically from the earliest minutes through days after the event."
        ),
        "ecg_changes": [
            "<b>Hyperacute T waves</b> – Earliest change (minutes): tall, broad, peaked T waves over ischemic zone",
            "<b>ST-segment elevation</b> – Convex/tombstone morphology; &gt;1mm in ≥2 contiguous limb leads; &gt;2mm in men (V2-V3), &gt;1.5mm in women",
            "<b>Reciprocal ST depression</b> – In opposite leads (e.g., inferior STEMI → ST depression in aVL)",
            "<b>Pathological Q waves</b> – Develop over hours-days; width &gt;40ms, depth &gt;25% of R wave",
            "<b>T-wave inversions</b> – Follow ST elevation as infarct evolves",
            "<b>Loss of R-wave amplitude</b> – As necrosis progresses",
        ],
        "table": {
            "headers": ["Territory", "Artery", "Leads with ST Elevation"],
            "rows": [
                ["Anterior", "LAD", "V1–V4"],
                ["Lateral", "LCx", "I, aVL, V5–V6"],
                ["Inferior", "RCA", "II, III, aVF"],
                ["Posterior", "RCA/LCx", "Reciprocal ST-dep V1–V3; add V7-V9"],
                ["Right Ventricle", "RCA", "V3R–V4R (right-sided leads)"],
            ]
        },
        "img_key": "wellens",
        "img_cap": "Figure: Severe anterior wall ischemia – Wellens sign (deep T-wave inversions V2–V6). Associated with high-grade LAD stenosis. Source: Harrison's 22E / LITFL",
        "pearl": "A normal ECG does not exclude STEMI. Serial ECGs every 15–30 min are essential when symptoms persist.",
    },
    {
        "num": "02",
        "title": "NSTEMI / Unstable Angina (ACS without ST Elevation)",
        "overview": (
            "NSTEMI and unstable angina represent subendocardial ischemia without complete coronary occlusion. "
            "Troponin distinguishes NSTEMI (elevated) from UA (normal). ECG may be dynamic and must be monitored serially."
        ),
        "ecg_changes": [
            "<b>ST depression</b> – Horizontal or downsloping ≥0.5mm; most specific for ischemia",
            "<b>T-wave inversions</b> – Symmetric, deep; often in multiple precordial leads",
            "<b>ST elevation in aVR</b> – Reciprocal to widespread subendocardial ischemia (indicates LM or proximal LAD disease)",
            "<b>Normal ECG</b> – Present in up to 30% of cases; does NOT exclude diagnosis",
            "<b>Transient ST elevation</b> – In Prinzmetal's (vasospastic) angina, resolves with nitroglycerin",
            "<b>No Q waves</b> – Subendocardial infarction typically does not produce Q waves",
        ],
        "table": None,
        "img_key": None,
        "img_cap": None,
        "pearl": "Horizontal or downsloping ST depression is more specific for ischemia than upsloping depression. Always obtain serial ECGs.",
    },
    {
        "num": "03",
        "title": "Atrial Fibrillation (AF)",
        "overview": (
            "AF is the most common sustained cardiac arrhythmia. The disorganized atrial electrical activity "
            "causes loss of coordinated atrial contraction, irregular ventricular response, and a risk of "
            "thromboembolic stroke. Prevalence increases sharply with age."
        ),
        "ecg_changes": [
            "<b>Absent P waves</b> – Replaced by chaotic fibrillatory baseline (f waves, 350–600 impulses/min)",
            "<b>Irregularly irregular RR intervals</b> – The hallmark; no two RR intervals are equal",
            "<b>Narrow QRS complexes</b> – Unless aberrant conduction or bundle branch block coexists",
            "<b>Ventricular rate 100–170 bpm</b> – Uncontrolled; slower when rate-controlled",
            "<b>Coarse vs. fine AF</b> – Coarse: f waves &gt;1mm (often seen in mitral valve disease); fine: barely visible",
            "<b>Wide complex AF</b> – Suspect WPW if very rapid (&gt;200 bpm) with irregular wide complexes (risk of VF)",
        ],
        "table": None,
        "img_key": "af",
        "img_cap": "Figure: Atrial Fibrillation – absent distinct P waves, chaotic fibrillatory baseline (coarse f-waves), irregularly irregular ventricular response. Source: LITFL ECG Library",
        "pearl": "In AF with rapid rate and wide QRS, always suspect WPW – avoid AV nodal blockers (digoxin, verapamil) as they can precipitate VF.",
    },
    {
        "num": "04",
        "title": "Complete Heart Block (3rd Degree AV Block)",
        "overview": (
            "In complete heart block, no atrial impulses conduct to the ventricles. The atria and ventricles "
            "beat independently. A subsidiary (escape) pacemaker maintains ventricular output at a slow rate. "
            "It is a potentially life-threatening bradyarrhythmia requiring urgent pacemaker implantation."
        ),
        "ecg_changes": [
            "<b>Complete AV dissociation</b> – P waves and QRS complexes bear NO relationship to each other",
            "<b>Regular P waves</b> – At sinus rate (60–100 bpm); P rate always FASTER than QRS rate",
            "<b>Regular, slow QRS complexes</b> – Escape rhythm at 20–60 bpm",
            "<b>Wide QRS (&gt;120ms)</b> – If escape is ventricular (infranodal block); narrow if junctional",
            "<b>Bradycardia</b> – Ventricular rate 20–60 bpm regardless of atrial rate",
            "<b>No PR interval correlation</b> – PR interval varies completely at random",
        ],
        "table": None,
        "img_key": "chb",
        "img_cap": "Figure: Complete Heart Block – regular P waves (~75 bpm) march through with no fixed relationship to the slow, wide escape QRS complexes (~35 bpm). Note complete AV dissociation. Source: LITFL ECG Library",
        "pearl": "Atropine is often ineffective in infranodal block. Transcutaneous pacing should be initiated while preparing for transvenous pacing.",
    },
    {
        "num": "05",
        "title": "Ventricular Tachycardia (VT)",
        "overview": (
            "VT arises from abnormal impulse generation in the ventricular myocardium, bypassing the "
            "normal conduction system. It can be haemodynamically stable or cause cardiovascular collapse. "
            "Monomorphic VT has a uniform QRS morphology; polymorphic VT (Torsades de Pointes) is associated with long QT."
        ),
        "ecg_changes": [
            "<b>Wide QRS tachycardia</b> – QRS &gt;120ms; rate 100–250 bpm (typically 150–200 bpm)",
            "<b>Regular rhythm</b> – Monomorphic VT; irregular in polymorphic VT",
            "<b>AV dissociation</b> – P waves independent of QRS (seen in ~50%); strongly suggests VT",
            "<b>Fusion beats</b> – Hybrid of sinus + ectopic QRS; pathognomonic of VT",
            "<b>Capture beats</b> – Occasional narrow QRS conducted from sinus node through AV node; pathognomonic",
            "<b>Concordance</b> – All precordial QRS complexes point same direction (positive or negative)",
            "<b>Brugada criteria / Josephson's sign</b> – Help differentiate VT from SVT with aberrancy",
        ],
        "table": None,
        "img_key": None,
        "img_cap": None,
        "pearl": "Any wide-complex tachycardia should be treated as VT until proven otherwise. AV dissociation, fusion, and capture beats are diagnostic of VT.",
    },
    {
        "num": "06",
        "title": "Left Ventricular Hypertrophy (LVH)",
        "overview": (
            "LVH results from sustained pressure or volume overload (hypertension, aortic stenosis, "
            "cardiomyopathy). It increases R-wave voltage in left-sided leads and may cause a repolarisation "
            "('strain') pattern. It is an independent predictor of cardiovascular morbidity and sudden death."
        ),
        "ecg_changes": [
            "<b>Increased QRS voltage</b> – SV1 + RV5 or RV6 &gt;35mm (Sokolow-Lyon criterion)",
            "<b>RaVL &gt;20mm (women)</b> or <b>&gt;28mm (men)</b> – Cornell voltage criterion",
            "<b>Left axis deviation</b> – QRS axis more negative than −30°",
            "<b>ST depression + T-wave inversion</b> – ('Strain pattern') in V5, V6, I, aVL with prominent R waves",
            "<b>Left atrial enlargement</b> – Broad bifid P wave in II (P mitrale); terminal negative P in V1 &gt;1mm deep",
            "<b>Prolonged QRS duration</b> – LVH can progress to LBBB",
        ],
        "table": None,
        "img_key": None,
        "img_cap": None,
        "pearl": "ECG voltage criteria for LVH have low sensitivity (~50%) but high specificity (~90%). Echocardiography is the gold standard for confirmation.",
    },
    {
        "num": "07",
        "title": "Right Bundle Branch Block (RBBB)",
        "overview": (
            "RBBB results from delayed conduction through the right bundle branch. It may be isolated "
            "(normal variant) or associated with structural disease (PE, RVH, ASD, ischaemia). "
            "Complete RBBB has QRS ≥120ms; incomplete RBBB has QRS 110–120ms."
        ),
        "ecg_changes": [
            "<b>QRS ≥120ms</b> – Wide complex due to delayed right ventricular activation",
            "<b>rSR' ('M-shaped') pattern in V1</b> – Terminal R' wave (right ventricular activation)",
            "<b>Wide, slurred S wave in I, V5, V6</b> – Terminal S wave = delayed right ventricular forces",
            "<b>ST depression + T-wave inversions in V1–V3</b> – Secondary (discordant) repolarisation changes",
            "<b>Normal or rightward QRS axis</b>",
            "<b>No change in R-wave progression</b> – Unlike LBBB, which disrupts septal activation",
        ],
        "table": None,
        "img_key": None,
        "img_cap": None,
        "pearl": "New RBBB in the setting of PE suggests right heart strain. Isolated RBBB in a young patient with syncope raises concern for Brugada syndrome.",
    },
    {
        "num": "08",
        "title": "Wolff-Parkinson-White Syndrome (WPW)",
        "overview": (
            "WPW involves an accessory pathway (Bundle of Kent) that bypasses the AV node, causing "
            "ventricular pre-excitation. The QRS is a fusion of pre-excited (accessory pathway) and "
            "normally conducted (AV node) activation. WPW can cause life-threatening arrhythmias."
        ),
        "ecg_changes": [
            "<b>Short PR interval (&lt;120ms)</b> – Accessory pathway bypasses AV nodal delay",
            "<b>Delta wave</b> – Slurred initial upstroke of QRS (slow pre-excitation via accessory pathway)",
            "<b>Wide QRS (&gt;120ms)</b> – Fusion of delta wave + normal conduction",
            "<b>Secondary ST-T changes</b> – Discordant repolarisation changes due to abnormal depolarisation",
            "<b>Pseudo-infarction Q waves</b> – Delta waves can mimic inferior or lateral Q waves",
            "<b>AVRT tachycardia</b> – Narrow complex (orthodromic) or wide complex (antidromic) re-entry",
        ],
        "table": None,
        "img_key": None,
        "img_cap": None,
        "pearl": "In WPW with AF, NEVER use AV nodal blockers (adenosine, verapamil, digoxin). Rapid conduction over the accessory pathway can cause ventricular fibrillation.",
    },
    {
        "num": "09",
        "title": "Acute Pericarditis",
        "overview": (
            "Pericarditis is inflammation of the pericardial sac, most commonly viral. "
            "The ECG evolves through 4 classic stages. The key challenge is differentiating it from STEMI, "
            "as both can present with ST elevation. PR depression is the most specific finding."
        ),
        "ecg_changes": [
            "<b>Stage 1 (hours–days)</b>: Diffuse <b>concave ST elevation</b> in all leads except aVR and V1; <b>PR depression</b> (most diagnostic sign)",
            "<b>Stage 2 (1st week)</b>: ST and PR return to baseline; T-wave flattening",
            "<b>Stage 3 (days–weeks)</b>: Diffuse T-wave inversions (after ST normalises)",
            "<b>Stage 4 (weeks–months)</b>: ECG normalisation (or persistent T-wave inversions)",
            "<b>ST elevation in II &gt; III</b> – Key differentiator from STEMI (in inferior STEMI, III &gt; II)",
            "<b>No reciprocal changes</b> – Except in aVR and V1 (unlike STEMI)",
            "<b>No Q waves</b> – Absence of pathological Q waves",
        ],
        "table": {
            "headers": ["Feature", "Pericarditis", "STEMI"],
            "rows": [
                ["ST shape", "Concave (saddle)", "Convex (tombstone)"],
                ["Lead distribution", "Diffuse (all leads)", "Territorial"],
                ["PR segment", "Depressed", "Normal"],
                ["Reciprocal changes", "Absent (except aVR)", "Present"],
                ["Q waves", "Absent", "Develop over hours"],
                ["II vs III ST elevation", "II > III", "III > II (inferior)"],
            ]
        },
        "img_key": None,
        "img_cap": None,
        "pearl": "PR depression in leads with ST elevation (especially lead II and V5–V6) is virtually pathognomonic of pericarditis and is the most reliable differentiating feature from STEMI.",
    },
    {
        "num": "10",
        "title": "Pulmonary Embolism (PE)",
        "overview": (
            "Acute PE causes acute right heart strain, which produces characteristic (though non-specific) "
            "ECG changes. The most common ECG finding is simply sinus tachycardia. "
            "The classic S1Q3T3 pattern is present in only ~20% of cases."
        ),
        "ecg_changes": [
            "<b>Sinus tachycardia</b> – Most common finding (~40% of cases); non-specific",
            "<b>S1Q3T3 pattern</b> – Deep S in lead I; Q wave and T-wave inversion in lead III (classic, ~20% sensitive)",
            "<b>T-wave inversions V1–V4</b> – Right heart strain pattern; most specific ECG sign",
            "<b>New RBBB (complete or incomplete)</b> – Acute right ventricular pressure overload",
            "<b>Right axis deviation</b> – QRS axis &gt;+90°",
            "<b>P pulmonale</b> – Tall peaked P wave in II (&gt;2.5mm); right atrial enlargement",
            "<b>Atrial arrhythmias</b> – AF or flutter (~10–15%)",
            "<b>Normal ECG</b> – Does NOT exclude PE; present in ~30% of cases",
        ],
        "table": None,
        "img_key": None,
        "img_cap": None,
        "pearl": "ECG is non-specific in PE. The combination of S1Q3T3 + new T-wave inversions V1–V4 + sinus tachycardia has higher sensitivity. D-dimer and CT-PA are required for diagnosis.",
    },
]

# ── QUICK REFERENCE TABLE (after cover) ─────────────────────────────────────
story.append(Paragraph("Quick Reference Summary", section_head))
story.append(Spacer(1, 4))

qr_headers = ["#", "Disease", "Key ECG Finding", "Diagnostic Pattern"]
qr_rows = [
    ["01", "STEMI",             "ST elevation + Q waves",         "Territorial, convex ST elevation"],
    ["02", "NSTEMI / UA",       "ST depression, T inversions",    "Horizontal/downsloping ST-dep"],
    ["03", "Atrial Fibrillation","No P waves, irregular RR",      "Irregularly irregular narrow QRS"],
    ["04", "Complete Heart Block","AV dissociation",              "P rate > QRS rate, independent"],
    ["05", "Ventricular Tachycardia","Wide QRS tachycardia",      "≥120ms QRS, ~150–200 bpm"],
    ["06", "LVH",               "Tall voltage + strain pattern",  "SV1+RV5 >35mm, ST-dep lateral leads"],
    ["07", "RBBB",              "rSR' V1, wide S in V5/V6",      "Terminal R' in V1, slurred S laterally"],
    ["08", "WPW Syndrome",      "Short PR + delta wave",          "Wide QRS, delta wave, PR <120ms"],
    ["09", "Pericarditis",      "Diffuse concave ST + PR-dep",    "All leads (except aVR/V1), saddle-shaped"],
    ["10", "Pulmonary Embolism","S1Q3T3 + right strain",          "Sinus tachy, RV strain pattern V1–V4"],
]

qr_col_w = [1.0*cm, 4.5*cm, 4.8*cm, 5.2*cm]
qr_data = [[Paragraph(h, table_head) for h in qr_headers]]
for row in qr_rows:
    qr_data.append([Paragraph(c, table_cell) for c in row])

qr_table = Table(qr_data, colWidths=qr_col_w, repeatRows=1)
qr_table.setStyle(TableStyle([
    ("BACKGROUND",   (0,0), (-1,0),  colors.HexColor("#C0392B")),
    ("BACKGROUND",   (0,1), (-1,1),  colors.HexColor("#FDECEA")),
    ("BACKGROUND",   (0,2), (-1,2),  colors.white),
    ("ROWBACKGROUNDS", (0,1), (-1,-1), [colors.HexColor("#FDECEA"), colors.white]),
    ("GRID",         (0,0), (-1,-1), 0.4, colors.HexColor("#E0E0E0")),
    ("TOPPADDING",   (0,0), (-1,-1), 5),
    ("BOTTOMPADDING",(0,0), (-1,-1), 5),
    ("LEFTPADDING",  (0,0), (-1,-1), 6),
    ("VALIGN",       (0,0), (-1,-1), "MIDDLE"),
]))
story.append(qr_table)
story.append(PageBreak())

# ── DISEASE SECTIONS ─────────────────────────────────────────────────────────
for d in diseases:
    # Section header
    header_data = [[Paragraph(f"{d['num']}  {d['title']}", section_head)]]
    header_table = Table(header_data, colWidths=[W - 2*MARGIN])
    header_table.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,-1), colors.HexColor("#C0392B")),
        ("TOPPADDING",    (0,0), (-1,-1), 8),
        ("BOTTOMPADDING", (0,0), (-1,-1), 8),
        ("LEFTPADDING",   (0,0), (-1,-1), 10),
    ]))
    story.append(header_table)
    story.append(Spacer(1, 6))

    # Overview
    story.append(Paragraph(d["overview"], body))
    story.append(Spacer(1, 4))

    # ECG Changes
    story.append(Paragraph("ECG Changes:", ParagraphStyle("SubHead", fontName="Helvetica-Bold",
                            fontSize=11, textColor=colors.HexColor("#2980B9"), spaceBefore=4, spaceAfter=4)))
    for b in d["ecg_changes"]:
        story.append(Paragraph(f"• &nbsp; {b}", bullet))

    # Table if present
    if d.get("table"):
        story.append(Spacer(1, 6))
        t = d["table"]
        col_count = len(t["headers"])
        t_col_w = [(W - 2*MARGIN) / col_count] * col_count
        t_data = [[Paragraph(h, table_head) for h in t["headers"]]]
        for row in t["rows"]:
            t_data.append([Paragraph(c, table_cell) for c in row])
        tbl = Table(t_data, colWidths=t_col_w, repeatRows=1)
        tbl.setStyle(TableStyle([
            ("BACKGROUND",   (0,0), (-1,0),  colors.HexColor("#2980B9")),
            ("ROWBACKGROUNDS", (0,1), (-1,-1), [colors.HexColor("#EBF5FB"), colors.white]),
            ("GRID",         (0,0), (-1,-1), 0.4, colors.HexColor("#D0D0D0")),
            ("TOPPADDING",   (0,0), (-1,-1), 5),
            ("BOTTOMPADDING",(0,0), (-1,-1), 5),
            ("LEFTPADDING",  (0,0), (-1,-1), 6),
            ("VALIGN",       (0,0), (-1,-1), "MIDDLE"),
        ]))
        story.append(tbl)

    # ECG image
    if d.get("img_key"):
        story.extend(ecg_image(d["img_key"], d["img_cap"]))

    # Clinical Pearl
    pearl_data = [[Paragraph(f"<b>Clinical Pearl:</b> {d['pearl']}",
                   ParagraphStyle("Pearl", fontName="Helvetica", fontSize=9,
                                  textColor=colors.HexColor("#1A5276"),
                                  leading=14))]]
    pearl_table = Table(pearl_data, colWidths=[W - 2*MARGIN])
    pearl_table.setStyle(TableStyle([
        ("BACKGROUND",    (0,0), (-1,-1), colors.HexColor("#D6EAF8")),
        ("BOX",           (0,0), (-1,-1), 1, colors.HexColor("#2980B9")),
        ("TOPPADDING",    (0,0), (-1,-1), 8),
        ("BOTTOMPADDING", (0,0), (-1,-1), 8),
        ("LEFTPADDING",   (0,0), (-1,-1), 10),
    ]))
    story.append(Spacer(1, 8))
    story.append(pearl_table)
    story.append(Spacer(1, 10))
    story.append(PageBreak())

# ── REFERENCES PAGE ──────────────────────────────────────────────────────────
story.append(Paragraph("References & Sources", section_head))
story.append(Spacer(1, 8))
refs = [
    "Harrison's Principles of Internal Medicine, 22nd Edition (2025). Chapter 247: Electrocardiography. McGraw Hill Medical.",
    "Goldman-Cecil Medicine, International Edition. Chapters 49–52: Electrocardiography and Arrhythmias. Elsevier.",
    "Life in the Fast Lane (LITFL) ECG Library. ecg.library.litfl.com – Atrial Fibrillation, Complete Heart Block, ECG patterns.",
    "European Society of Cardiology (ESC). Diagnosis of Acute Pericarditis. ESC eJournal Volume 15.",
    "AHA/ACCF/HRS Recommendations for Standardization and Interpretation of the ECG. Journal of the American College of Cardiology, 2009.",
    "Brugada P, et al. A new approach to the differential diagnosis of a regular tachycardia with a wide QRS complex. Circulation 1991.",
    "Sgarbossa EB, et al. Electrocardiographic diagnosis of evolving AMI in the presence of LBBB. NEJM 1996.",
]
for i, r in enumerate(refs, 1):
    story.append(Paragraph(f"{i}. {r}", ParagraphStyle("Ref", fontName="Helvetica", fontSize=9,
                            textColor=colors.HexColor("#2C3E50"), leading=14, spaceAfter=6,
                            leftIndent=12, firstLineIndent=-12)))

story.append(Spacer(1, 1*cm))
story.append(HRFlowable(width="100%", thickness=0.5, color=colors.grey))
story.append(Spacer(1, 6))
story.append(Paragraph(
    "<b>Disclaimer:</b> This document is for educational purposes only. ECG interpretation must always be "
    "integrated with the clinical history, physical examination, and appropriate investigations. "
    "Clinical decisions should not be made solely on the basis of this reference material.",
    ParagraphStyle("Disclaimer", fontName="Helvetica-Oblique", fontSize=8,
                   textColor=colors.grey, leading=12, alignment=TA_JUSTIFY)
))

# ── BUILD PDF ────────────────────────────────────────────────────────────────
doc = SimpleDocTemplate(
    OUTPUT,
    pagesize=A4,
    leftMargin=MARGIN, rightMargin=MARGIN,
    topMargin=2*cm, bottomMargin=1.5*cm,
    title="10 Common Heart Diseases with ECG Changes",
    author="Orris AI",
    subject="Cardiology ECG Reference",
)

doc.build(story, onFirstPage=on_page, onLaterPages=on_page)
print(f"PDF generated: {OUTPUT}")