Syncope, a Low Ejection Fraction and a Wide LBBB Three Months After Anterior MI
A 58-year-old man is reviewed in clinic 3 months after an anterior ST-elevation MI treated with primary PCI to the left anterior descending artery. He is NYHA class II, BP 112/70, pulse 68. Medication: sacubitril/valsartan 97/103 mg twice daily, bisoprolol 5 mg, eplerenone 25 mg, empagliflozin 10 mg, atorvastatin 80 mg, aspirin 75 mg. Echocardiography yesterday: LVEF 32%, moderate left ventricular dilatation, no significant valvular disease. ECG: sinus rhythm, QRS 152 ms with typical LBBB. eGFR 52 mL/min/1.73 m², potassium 4.6 mmol/L. He has had two collapses in the last 3 weeks: the first while standing after a hot shower, the second while sitting watching television with no warning, no injury and no recall of the event. He denies palpitations. A 24-hour Holter showed frequent ventricular ectopy and one 4-beat run of non-sustained VT at 180 bpm, with no pauses. He asks whether he needs 'the shock box' and whether it can wait until after his daughter's wedding in 2 months.
1. Does he currently satisfy criteria for a primary-prevention device, and if so which device? Justify the choice of device type.
Read the worked answer
Yes, but the correct device is a CRT-D, not an ICD alone.
Primary-prevention ICD criteria in ischaemic cardiomyopathy: LVEF ≤35% despite ≥40 days after MI and ≥90 days after revascularisation, NYHA II–III, on guideline-directed medical therapy, with a reasonable expectation of survival with good function beyond 1 year. At 3 months post-MI and on tolerated neurohormonal blockade he meets all of these.
CRT criteria: sinus rhythm, LBBB with QRS ≥150 ms, LVEF ≤35%, NYHA II–IV - a class I indication. He has QRS 152 ms and typical LBBB, so CRT is indicated and, because he has ischaemic cardiomyopathy with a primary-prevention indication, the defibrillator component is added (CRT-D). A CRT-P would forgo defibrillation in a patient with LVEF 32% and documented ventricular arrhythmia, which is not appropriate here.
Before implanting, confirm that the potassium, renal function and blood pressure allow continued sacubitril/valsartan, eplerenone and beta-blocker therapy; bisoprolol 5 mg is not maximal (up to 10 mg), so document why higher doses were not tolerated. LVEF should not be re-measured again as a reason to delay - 3 months of therapy is the required minimum, not a target to exceed.
2. How does the syncope alter your assessment and what work-up should precede implantation?
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Syncope in a patient with LVEF 32%, ischaemic scar and non-sustained VT must be treated as arrhythmic until proven otherwise, even though the first event was postural. The second event had no prodrome, no trigger and no recall - a high-risk feature. Non-sustained VT plus syncope is a warning of sustained ventricular tachyarrhythmia, so admission with continuous telemetry is appropriate rather than outpatient investigation.
Work-up should address reversible and competing causes:
- Ischaemia: he had PCI 3 months ago; assess for restenosis or a new lesion (stress imaging or angiography if symptoms or ECG changes suggest it).
- Electrolytes, glucose, drugs: potassium, magnesium, thyroid function, and review for QT-prolonging agents.
- Structural disease: cardiac MRI to quantify scar and exclude infiltrative or sarcoid disease, which would change device and immunosuppression decisions and help plan VT ablation.
- Rhythm: prolonged monitoring; an implantable loop recorder is unnecessary if a device is already indicated.
- Orthostatic and reflex causes: lying/standing BP, volume status - but a normal work-up for these does not overturn the indication.
If telemetry captures sustained VT, the indication becomes secondary prevention and the device should not be deferred for any non-urgent reason.
3. He insists on postponing the implant until after the wedding. How do you counsel him, and what else must be optimised?
Read the worked answer
Counsel that the syncope, not the calendar, dictates timing. A 4-beat run of VT at 180 bpm with unexplained syncope means the next episode could be sustained VT or ventricular fibrillation, and the window of protection is precisely what an implantable device provides. A wedding in 2 months is not a reason to accept that risk; if he wishes, the procedure can be scheduled within days and convalescence planned around the event.
Practical points to cover:
- Implant a MRI-conditional CRT-D system, since he may need imaging of scar or spine later.
- Quote realistic complication rates: pneumothorax, lead displacement, device infection (~1–2%), inappropriate shocks; CRT response is not guaranteed and some patients remain symptomatic.
- Driving: advise against driving until reviewed after implant, in line with local licensing rules, and explain the implications of any future shock.
- Optimise therapy: uptitrate bisoprolol if tolerated, continue sacubitril/valsartan, eplerenone and empagliflozin, reinforce adherence and cardiac rehabilitation; treat anaemia and sleep apnoea if present.
- Ask him to report presyncope, palpitations or shocks immediately; discuss remote monitoring enrolment.
If he declines, document the discussion, arrange an early review, and consider a wearable defibrillator as a bridge while he decides.