10 Common Heart Diseases: ECG Changes & Management

1. 🫀 ST-Elevation Myocardial Infarction (STEMI)

ECG Changes

• Hyperacute T-waves (earliest sign — tall, peaked, asymmetric)
• ST-segment elevation ≥1 mm in ≥2 contiguous limb leads, or ≥2 mm in ≥2 contiguous precordial leads (convex/tombstone morphology)
• Pathological Q waves (transmural necrosis — emerge within hours)
• Reciprocal ST depression in opposing leads
• Lead localization: anterior (V1–V4 = LAD), inferior (II, III, aVF = RCA), lateral (I, aVL, V5–V6 = LCx)

Management (2023 ACC/AHA/ESC Guidelines)

• Primary PCI within 90 min of first medical contact (FMC-to-balloon ≤90 min) — Class I
• Fibrinolysis if PCI not available within 120 min of diagnosis — Class I
• Antiplatelet: Aspirin 325 mg + P2Y12 inhibitor (ticagrelor 180 mg or prasugrel 60 mg preferred over clopidogrel) — Class I
• Anticoagulation: UFH, enoxaparin, or bivalirudin during PCI — Class I
• Beta-blockers: oral within 24 h if no cardiogenic shock — Class I
• ACE inhibitor/ARB: for all STEMI patients, especially with reduced EF — Class I
• High-intensity statin: immediately (atorvastatin 80 mg or rosuvastatin 40 mg) — Class I
• Coronary angiography of non-culprit vessels: staged PCI in haemodynamically stable patients

2. 🫀 Non-ST-Elevation ACS (NSTEMI/Unstable Angina)

ECG Changes

• ST depression ≥0.5 mm (horizontal or downsloping) in ≥2 contiguous leads
• T-wave inversions (symmetric, deep — especially in anterior leads with proximal LAD lesion)
• Transient ST elevation possible (Prinzmetal variant)
• Normal ECG in up to 30–50% of cases — does NOT exclude NSTEMI
• De Winter T-waves (upsloping ST depression + tall symmetric T-waves in V1–V5) — LAD equivalent

Management (2023 ESC NSTE-ACS Guidelines)

• Risk stratification: GRACE score for mortality risk; HEART score for 30-day MACE
• Antiplatelet: Aspirin + ticagrelor (preferred) or clopidogrel — Class I
• Anticoagulation: fondaparinux (preferred), enoxaparin, or UFH — Class I
• Invasive strategy timing:
  • Immediate (<2 h): refractory angina, haemodynamic instability, life-threatening arrhythmia
  • Early (<24 h): GRACE >140 or dynamic ECG/troponin changes
  • Selective (24–72 h): stable intermediate-risk patients
• Beta-blocker, statin, ACE inhibitor/ARB as for STEMI

3. 💓 Atrial Fibrillation (AF)

ECG Changes

• Irregularly irregular RR intervals (hallmark)
• Absent P waves — replaced by chaotic fibrillatory baseline (best seen in V1)
• Narrow QRS complexes unless aberrant conduction or accessory pathway
• Rapid ventricular response (AF with RVR) if rate >100 bpm
• Variable QRS amplitude

Management (2023 ACC/AHA AF Guidelines)

• Anticoagulation: CHA₂DS₂-VASc score ≥2 (men) or ≥3 (women) → DOACs (apixaban, rivaroxaban, edoxaban, dabigatran) preferred over warfarin — Class I
• Rate control: beta-blockers or non-DHP calcium channel blockers; target HR <110 bpm (lenient) — Class I
• Rhythm control: early rhythm control within 1 year of diagnosis reduces cardiovascular outcomes (EAST-AFNET 4 trial) — Class IIa
• Cardioversion: safe if AF <48 h, or after ≥3 weeks anticoagulation
• Catheter ablation: pulmonary vein isolation — Class I for symptomatic paroxysmal AF after failed antiarrhythmic drug (Class IIa for first-line)
• Treat underlying conditions: hypertension, sleep apnoea, obesity, alcohol

4. 💔 Heart Failure with Reduced EF (HFrEF)

ECG Changes

• Left bundle branch block (LBBB): QRS >120 ms, broad monophasic R in I/aVL/V5–V6, deep S in V1 — strongly associated with DCM
• Left ventricular hypertrophy: high voltage (Sokolow-Lyon: SV1 + RV5 >35 mm)
• Sinus tachycardia: compensatory
• Low voltage: if pericardial effusion or severe LV dilation
• Atrial fibrillation: very common comorbidity
• Ventricular ectopy / NSVT: risk marker

Management (2022 AHA/ACC/HFSA Guidelines — "Fantastic Four")

• ACE inhibitor/ARB/ARNI (sacubitril-valsartan preferred over ACEi) — Class I
• Beta-blocker (carvedilol, metoprolol succinate, bisoprolol) — Class I
• MRA (spironolactone or eplerenone) — Class I
• SGLT2 inhibitor (dapagliflozin or empagliflozin) — Class I (new addition)
• Diuretics for fluid overload: loop diuretics (furosemide) — Class I
• CRT (Cardiac Resynchronisation Therapy): LBBB + QRS ≥150 ms + EF ≤35% — Class I
• ICD: EF ≤35% despite ≥3 months GDMT, NYHA II–III — Class I
• LVAD / Heart transplantation: stage D refractory HF

5. ❤️ Complete (3rd Degree) AV Heart Block

ECG Changes

• Complete AV dissociation: P waves and QRS complexes march independently
• Atrial rate > ventricular rate
• Ventricular escape rhythm: junctional (narrow QRS, rate 40–60 bpm) or ventricular (wide QRS, rate 20–40 bpm)
• No fixed PR interval — P waves appear before, within, and after QRS complexes
• Bradycardia (often <40 bpm)

Management (2024 ACC/AHA Bradycardia/CDS Guidelines)

• Urgent temporary pacing: transcutaneous or transvenous if haemodynamically unstable — Class I
• Permanent pacemaker: virtually all patients with acquired complete heart block — Class I
• Dual-chamber pacemaker (DDD): preferred to preserve AV synchrony — Class I
• His bundle pacing / LBBP: preferred over RV apical pacing if available (Class IIa)
• Treat reversible causes: Lyme disease, drug toxicity (digoxin, beta-blockers), inferior MI (temporary — may resolve)
• Atropine (0.5–1 mg IV): temporising measure for vagally-mediated block — Class IIb
• Dopamine/epinephrine infusion: if atropine fails and pacing not immediately available

6. ⚡ Ventricular Tachycardia (VT)

ECG Changes

• Wide complex tachycardia: QRS ≥120 ms at rate >100 bpm (usually 150–250 bpm)
• AV dissociation: P waves independent of QRS (pathognomonic) — best seen in long rhythm strip
• Capture beats and fusion beats (highly specific for VT)
• Concordance: positive (all V1–V6 positive) or negative concordance — strongly suggests VT
• Brugada criteria / Vereckei criteria: used to differentiate VT from SVT with aberrancy
• Monomorphic VT: regular, identical QRS morphology
• Polymorphic VT / Torsades de Pointes: twisting QRS axis around baseline, associated with long QT

Management (2022 ESC Ventricular Arrhythmia Guidelines)

• Haemodynamically unstable: immediate DC cardioversion (synchronised) — Class I
• Haemodynamically stable monomorphic VT: IV amiodarone (150 mg bolus then 1 mg/min) or procainamide — Class I
• ICD implantation: secondary prevention after survived cardiac arrest; primary prevention if EF ≤35% — Class I
• Catheter ablation: recurrent VT despite antiarrhythmic drugs, or VT storm — Class I
• Torsades de Pointes: IV magnesium sulphate 2 g; correct QT-prolonging drugs and electrolytes
• Beta-blockers: reduce VT burden in structural heart disease — Class I
• Amiodarone: for VT suppression when ICD therapy is frequent

7. 🔄 Wolff-Parkinson-White (WPW) Syndrome

ECG Changes

• Short PR interval (<120 ms) — bypass of AV node via accessory pathway (Bundle of Kent)
• Delta wave: slurred upstroke at start of QRS (pre-excitation)
• Wide QRS (>120 ms): fusion of delta wave + normal conduction
• Secondary ST-T changes: discordant repolarisation
• Pseudo-infarct pattern: negative delta waves in inferior leads mimicking Q waves
• AVRT (orthodromic): narrow complex SVT with retrograde P waves after QRS
• AF with WPW: irregular wide complex tachycardia with rapid rate (>250 bpm) → risk of VF

Management (2019 ESC SVT Guidelines, updated recommendations)

• Asymptomatic WPW: risk stratification with electrophysiology (EP) study — Class IIa; ablation if high-risk accessory pathway
• Symptomatic WPW (AVRT): catheter ablation of accessory pathway — Class I (first-line, >95% success)
• Acute AVRT termination: vagal manoeuvres, adenosine (6–12 mg IV) — Class I
• AF + WPW: NEVER use AV nodal blocking agents (adenosine, verapamil, digoxin, beta-blockers) — risk of fatal VF
• AF + WPW acute: DC cardioversion (haemodynamically unstable) or IV procainamide/ibutilide
• Pre-excitation on ECG in athletes: mandatory EP study and ablation if high-risk

8. 🧱 Hypertrophic Cardiomyopathy (HCM)

ECG Changes

• Left ventricular hypertrophy (LVH): high QRS voltage in precordial leads (Sokolow ≥35 mm)
• Deep, "dagger-like" Q waves: septal hypertrophy in I, aVL, V5–V6
• Apical HCM (Yamaguchi): giant T-wave inversions in V2–V5 (depth ≥10–30 mm)
• ST-segment depression + T-wave inversion (strain pattern) in lateral leads
• P-wave abnormalities: left atrial enlargement
• Absence of septal Q waves in lateral leads (paradoxically absent due to reversed septal depolarisation)

Management (2024 ACC/AHA HCM Guidelines)

• Lifestyle: avoid dehydration, competitive sports (consult cardiologist)
• Obstructive HCM (LVOTO): mavacamten (cardiac myosin inhibitor) — Class I (new guideline addition 2024); first-line before septal reduction
• Beta-blockers or verapamil: for symptom relief, LVOT obstruction — Class I
• Septal reduction: surgical septal myectomy (Class I for refractory NYHA III–IV) or alcohol septal ablation (Class IIa)
• ICD: for primary prevention — risk factors include family history of SCD, LV thickness ≥30 mm, unexplained syncope, NSVT, abnormal BP response to exercise
• HCM Risk-SCD calculator (ESC): used for 5-year SCD risk estimation
• AF management: anticoagulation regardless of CHA₂DS₂-VASc score in HCM + AF

9. 🫧 Acute Pericarditis

ECG Changes (Classic 4-Stage Evolution)

• Stage 1 (days 1–2): Diffuse concave ("saddle-shaped") ST elevation in all leads except aVR and V1; PR depression in II, V4–V6; PR elevation in aVR (pathognomonic)
• Stage 2 (days 3–7): ST normalises, T waves flatten
• Stage 3: T-wave inversion (diffuse)
• Stage 4: ECG normalises
• Spodick's sign: downsloping TP segment
• Key differentiator from STEMI: diffuse (not regional), concave ST, no Q waves, PR depression

Management (2015 ESC Pericardial Disease Guidelines — current standard)

• First-line: NSAIDs (aspirin 750–1000 mg TDS or ibuprofen 600 mg TDS) + colchicine 0.5 mg BD for 3 months — Class I (reduces recurrence by 50%)
• Gastroprotection: proton pump inhibitor with NSAIDs — Class I
• Restrict exercise: until symptoms resolve and CRP normalises (athletes: 3 months minimum)
• Corticosteroids: only if NSAIDs/colchicine contraindicated, or connective tissue disease — low dose (prednisone 0.2–0.5 mg/kg/day), NOT first-line (increases recurrence)
• Recurrent pericarditis: colchicine ± IL-1 antagonist (anakinra, rilonacept) — Class IIa/IIb
• Hospitalisation: for high-risk features (fever >38°C, large effusion, tamponade, immunosuppressed)
• Cardiac tamponade: urgent pericardiocentesis

10. 🩸 Pulmonary Embolism (PE)

ECG Changes

• Sinus tachycardia: most common (>40% of cases)
• S1Q3T3 pattern: S wave in lead I + Q wave in lead III + T-wave inversion in lead III (classic but only in ~20%)
• Right bundle branch block (RBBB): complete or incomplete — right ventricular strain
• T-wave inversions in V1–V4 (right heart strain) — most specific ECG finding for massive PE
• P-pulmonale: tall peaked P waves in II (right atrial enlargement)
• Right axis deviation
• New AF may be precipitated

Management (2023 ESC PE Guidelines)

• Risk stratification: PESI score + RV dysfunction + troponin → massive / submassive / low-risk
• Anticoagulation (start immediately if clinical suspicion high, before confirmed):
  • DOACs (rivaroxaban or apixaban) — preferred first-line for most patients — Class I
  • LMWH → warfarin (if DOAC contraindicated)
  • Duration: 3 months minimum; extended if unprovoked or recurrent
• Massive PE (haemodynamic instability): systemic thrombolysis (alteplase 100 mg over 2 h) — Class I
• Surgical embolectomy or catheter-directed thrombolysis: if thrombolysis fails or contraindicated — Class I/IIa
• Submassive PE (RV dysfunction, no shock): consider thrombolysis if clinical deterioration — Class IIa
• PERC rule: if low pretest probability + all 8 PERC criteria negative → no further workup needed
• CTPA: diagnostic standard; V/Q scan if renal impairment or contrast allergy
• IVC filter: only if anticoagulation absolutely contraindicated

Quick Reference Table

Sources: Braunwald's Heart Disease (12th ed.), Goldman-Cecil Medicine, Rosen's Emergency Medicine; ACC/AHA/ESC Guidelines 2022–2024. ECG images from peer-reviewed clinical literature (PMC).Here's a summary of what was covered across all 10 conditions:

1. STEMI — ST elevation/tombstone morphology/Q waves → Primary PCI ≤90 min + dual antiplatelet + statin + ACEI
2. NSTEMI/Unstable Angina — ST depression/T-wave inversions/normal ECG → Risk-stratified invasive strategy + ticagrelor + anticoagulation
3. Atrial Fibrillation — Irregularly irregular, absent P waves → DOACs + rate/rhythm control; catheter ablation for symptomatic AF
4. HFrEF — LBBB, LVH, sinus tachycardia → The "Fantastic Four": ARNI + beta-blocker + MRA + SGLT2 inhibitor
5. Complete Heart Block — AV dissociation, escape rhythm → Permanent pacemaker (virtually all acquired cases)
6. Ventricular Tachycardia — Wide complex tachycardia, AV dissociation → DC cardioversion if unstable; amiodarone if stable; ICD
7. WPW Syndrome — Short PR + delta wave → Catheter ablation (first-line, >95% success); avoid AV nodal blockers in AF+WPW
8. Hypertrophic Cardiomyopathy — LVH + giant T-wave inversions → Mavacamten (new 2024 Class I); septal myectomy; ICD for SCD risk
9. Acute Pericarditis — Diffuse saddle-shaped ST elevation + PR depression → NSAIDs + colchicine for 3 months
10. Pulmonary Embolism — S1Q3T3 + sinus tachycardia + RV strain → DOACs; systemic thrombolysis for massive PE