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Stem
A 64-year-old man with a prior anterior STEMI 2 years ago (current LVEF 28% on bisoprolol, ramipril, spironolactone, empagliflozin, furosemide) is brought to the emergency department with 30 minutes of severe palpitations and dyspnoea. On examination he is clammy and confused, BP 78/48 mmHg, HR 190/min, JVP elevated, bibasal crackles. The monitor shows a regular broad-complex tachycardia at 190 bpm with QRS 160 ms and AV dissociation (occasional capture beats visible).
Questions
a) Diagnosis and the single most important decision in his management. (2 marks)
Diagnosis: sustained ventricular tachycardia (VT) — broad-complex (QRS over 120 ms) tachycardia at over 100 bpm in a patient with prior MI and ischaemic cardiomyopathy; capture beats and AV dissociation are pathognomonic. The decisive clinical decision is haemodynamic stability: this patient is unstable (hypotension 78/48 mmHg, confusion, clamminess, pulmonary oedema) — this branches the algorithm to electricity, not drugs.
b) Immediate management. (3 marks)
- ABCDE: oxygen if hypoxic, two large-bore cannulae, continuous cardiac monitoring, defibrillator pads attached, IV access.
- Synchronised DC cardioversion 100 J biphasic, escalating to 200 J if needed (sync to the R wave — never deliver unsynchronised in a perfusing rhythm or you will hit the T wave and precipitate VF).
- Pre-sedate with midazolam 2.5 to 5 mg IV plus fentanyl 50 to 100 µg IV only if time permits; do not delay cardioversion in the unstable patient.
- If cardioversion fails or VT recurs: IV amiodarone 300 mg over 20 to 60 minutes before further cardioversion.
- Do not give verapamil or adenosine to an undifferentiated broad-complex tachycardia.
c) Long-term management to reduce his risk of sudden cardiac death. (3 marks)
This patient meets criteria for primary-prevention ICD:
- LV ejection fraction under 35% (28%), NYHA class II to III on optimal medical therapy for at least 3 months, more than 40 days after MI and more than 3 months after revascularisation (the MADIT-II and SCD-HeFT criteria). His MI was 2 years ago, so the time criteria are satisfied.
- SCD-HeFT showed a 23% relative reduction in mortality with ICD in this exact population (NYHA II to III, EF under 35%).
- Continue optimal medical therapy (the four pillars of HFrEF: beta-blocker, ACEi/ARNI, MRA, SGLT2 inhibitor) — these reduce both HF mortality and arrhythmic death.
- Consider catheter ablation if scar-related VT is recurrent despite ICD.
d) Two complications of an ICD and one specific contraindication to implantation in the early post-MI period. (2 marks)
Complications (any two): inappropriate shocks (typically AF with rapid rate, sinus tachycardia, T-wave oversensing); pocket infection; lead fracture or failure; pneumothorax; cardiac tamponade from perforation; Twiddler's syndrome; psychological morbidity from shocks (depression, anxiety, PTSD).
Contraindication: ICD implantation within 40 days of acute MI — DINAMIT (Hohnloser NEJM 2004) showed no overall mortality benefit and excess non-arrhythmic death because the LV may yet recover; the same applies within 3 months of CABG/PCI.