ICD and CRT in heart failure — structured written assessment

SAQ 1 (10 marks)

Practice scenario. A 59-year-old man had an anterior ST-elevation myocardial infarction (MI) 10 weeks ago, treated with primary percutaneous coronary intervention with complete revascularization. He had no previously known left ventricular dysfunction. His pre-discharge left ventricular ejection fraction (LVEF) was 30%. Foundational medical therapy (FMT) has been uptitrated over the last 8 weeks, and today his LVEF is 32%. He has New York Heart Association (NYHA) class II symptoms, sinus rhythm, a QRS duration of 104 ms, no documented ventricular arrhythmia, and is expected to survive longer than 1 year with good functional status.^[3][1][8]

1. Distinguish primary-prevention from secondary-prevention implantable cardioverter-defibrillator (ICD) therapy. (1)^[1]
2. State the 2026 European Society of Cardiology (ESC) heart failure row for an ICD in ischaemic heart failure with reduced ejection fraction (HFrEF), with every condition and its class and level. (2)^[1]
3. Does he meet that ESC 2026 row today? Explain. (2)^[1]
4. Under the 2025 American College of Cardiology/American Heart Association (ACC/AHA) acute coronary syndrome guideline, what timing conditions apply, and are they met today? (2)^[8]
5. Which ESC row governs the LVEF re-evaluation after his MI? (1)^[9]
6. What risk does ESC 2026 attach to delaying an ICD? (1)^[1]
7. Would a wearable cardioverter-defibrillator (WCD) have been routinely indicated in his early post-MI phase? Give one guideline statement. (1)^[3]

Model answers — SAQ 1

1. Secondary prevention: an ICD after a ventricular arrhythmia causing haemodynamic instability, as in the ESC 2026 secondary-prevention row; primary prevention: an ICD before such an event, based on LVEF thresholds and aetiology (1 mark).^[1]
2. ESC 2026 recommends an ICD in patients with symptomatic HFrEF (NYHA class II/III) of an ischaemic aetiology (unless they have had an MI in the prior 40 days), and an LVEF ≤35% despite ≥3 months of optimal FMT, provided they are expected to survive longer than 1 year with good functional status, to reduce the risk of sudden death and all-cause death (1 mark for the conditions).^[1] Class I, Level B1 (1 mark).^[1]
3. Not yet: the MI was more than 40 days ago and his LVEF is ≤35%, but he has had only 8 weeks of uptitration, not ≥3 months of optimal FMT (1 mark).^[1] ESC 2026 text (no class or level given) calls a 3-month period after uptitration of FMT before considering ICD implantation reasonable, and 2022 AHA/ACC/HFSA finds repeat measurement of EF useful to inform therapeutic interventions in patients who have received GDMT and are being considered for device therapy (COR 1, LOE C-LD) (1 mark).^[1][5]
4. The 2025 ACC/AHA ACS guideline recommends an ICD in selected post-MI patients with LVEF ≤40% (its Table 17) at least 40 days post MI and at least 90 days postrevascularization, to reduce death (COR 1, LOE A); his LVEF of 32% with NYHA class II falls in the Table 17 category of 31%–35% with NYHA class II or III (1 mark).^[8] He is more than 40 days post MI but only about 70 days after his percutaneous coronary intervention, so the 90-day postrevascularization condition is not yet met (1 mark).^[8] The 2022 AHA/ACC/HFSA row (ICD for primary prevention of sudden cardiac death (SCD) to reduce total mortality at least 40 days post-MI, LVEF ≤35%, NYHA class II or III on chronic GDMT, expected meaningful survival >1 year; COR 1, LOE A) is the earlier North American row and needs chronic GDMT; its supportive text puts EF re-evaluation >90 days after revascularization and >90 days after GDMT (no extra mark).^[5]
5. The 2023 ESC ACS row: in patients with pre-discharge LVEF ≤40%, repeat evaluation of LVEF 6–12 weeks after an ACS (and after complete revascularization and the institution of optimal medical therapy) is recommended to assess the potential need for primary-prevention ICD implantation (Class I, Level C) (1 mark).^[9] ESC 2022 had given a similar row: in patients with pre-discharge LVEF ≤40%, re-evaluation of LVEF 6–12 weeks after MI is recommended to assess the potential need for primary-prevention ICD implantation (Class I, Level C) (no extra mark).^[3]
6. ESC 2026: delaying ICD implantation carries a risk of SCD of 2%–4% by 6 months and ∼7% by 1 year (1 mark).^[1]
7. No: ESC 2022 states that its task force does not recommend routine use of the WCD in the early post-MI phase, after the VEST trial showed no difference in arrhythmic death at 90 days (1 mark).^[3] Selected patients are covered by the 2023 ESC ACS row: ICD implantation or the temporary use of a WCD may be considered <40 days after MI with incomplete revascularization, pre-existing LVEF dysfunction, arrhythmias >48 h after ST-elevation MI onset, or polymorphic VT or VF (Class IIb, Level C); he had none of these, and for a primary-prevention ICD the later ESC 2026 HF row is a Class III row, not recommended within 40 days of an MI (no extra mark).^[9][1] For patients with HF, the later ESC 2026 row says a WCD may be considered in patients with HF at risk of SCD for a limited period, to increase survival as a bridge to decision for permanent ICD implantation or while listed for heart transplantation (Class IIb, Level C); that is not routine use (no extra mark).^[1]

SAQ 2 (10 marks)

Practice scenario. A 71-year-old woman has dilated cardiomyopathy of non-ischaemic aetiology with symptomatic heart failure with reduced ejection fraction (HFrEF), New York Heart Association (NYHA) class III symptoms and a left ventricular ejection fraction (LVEF) of 27% despite 6 months of optimal foundational medical therapy (FMT). She is in sinus rhythm with left bundle branch block (LBBB) and a QRS duration of 142 ms, and is expected to survive longer than 1 year with good functional status.^[1]

1. How does the 2026 European Society of Cardiology (ESC) heart failure guideline grade cardiac resynchronization therapy (CRT) for her, and how had the earlier 2021 ESC pacing guideline graded the same group? (2)^[1][2]
2. How do the 2022 American Heart Association/American College of Cardiology/Heart Failure Society of America (AHA/ACC/HFSA) guideline and the 2023 Heart Rhythm Society (HRS) guideline grade CRT for her? (2)^[5][6]
3. How does ESC 2026 grade a primary-prevention implantable cardioverter-defibrillator (ICD) for her, and what do ESC 2021 rows say about adding a defibrillator to CRT? (2)^[1][2]
4. Coronary sinus lead implantation fails. What do ESC 2021, HRS 2023 and ESC 2026 say about conduction system pacing (CSP)? (3)^[2][6][1]
5. What does ESC 2026 say about follow-up after CRT? (1)^[1]

Model answers — SAQ 2

1. ESC 2026: CRT should be considered in symptomatic HFrEF, LVEF ≤35%, despite optimal FMT, in sinus rhythm with LBBB QRS morphology and QRS duration of 130–149 ms, in order to improve symptoms and reduce morbidity and death (Class IIa, Level C) (1 mark).^[1] ESC 2021 (dated) graded the same group, symptomatic patients with HF in sinus rhythm with LVEF ≤35%, QRS 130–149 ms and LBBB despite optimal medical therapy, as Class IIa, Level B (1 mark).^[2]
2. 2022 AHA/ACC/HFSA: with LVEF ≤35%, sinus rhythm, LBBB with QRS 120 to 149 ms and NYHA class II, III or ambulatory IV symptoms on GDMT, CRT can be useful to reduce total mortality, reduce hospitalizations, and improve symptoms and QOL (COR 2a, LOE B-NR) (1 mark).^[5] HRS 2023: in patients with select characteristics (eg, female sex) with LVEF ≤35%, sinus rhythm, LBBB with QRS 120–149 ms and NYHA class II-IV symptoms on GDMT, CRT with biventricular pacing is recommended to reduce mortality and HF events and to improve LVEF (COR 1, LOE A) (1 mark).^[6]
3. ESC 2026: an ICD should be considered in symptomatic HFrEF (NYHA class II/III) of non-ischaemic aetiology with LVEF ≤35% despite ≥3 months of optimal FMT, provided survival longer than 1 year with good functional status is expected, to reduce the risk of sudden death and all-cause death (Class IIa, Level B1) (1 mark).^[1] ESC 2021: in ICD candidates with a CRT indication, a CRT-D is recommended (Class I, Level A); in CRT candidates, a CRT-D should be considered after individual risk assessment and using shared decision-making (Class IIa, Level B) (1 mark).^[2] ESC 2021 text adds that observational data point towards significant survival benefits by CRT-D over CRT-P in ischaemic cardiomyopathy, while no clear benefit has been shown in non-ischaemic cardiomyopathy (no extra mark).^[2] The ESC 2023 cardiomyopathy DCM row (ICD should be considered to reduce the risk of sudden death and all-cause mortality with symptomatic heart failure and LVEF ≤35% despite >3 months of optimal medical therapy; Class IIa, Level A) is covered for her, NYHA class III with expected survival >1 year, by the later ESC 2026 row (no extra mark).^[4][1]
4. The earlier ESC 2021 row: in CRT candidates in whom coronary sinus lead implantation is unsuccessful, His bundle pacing should be considered as a treatment option along with other techniques such as a surgical epicardial lead (Class IIa, Level B); for her HFrEF, the later ESC 2026 statement below is the ESC position (1 mark).^[2][1] HRS 2023: in patients undergoing CRT with biventricular pacing implantation via the coronary sinus, crossover to CSP with His bundle pacing or left bundle branch area pacing is reasonable when the coronary sinus left ventricular lead placement is unsuccessful or suboptimal (COR 2a, LOE C-LD) (1 mark).^[6] HRS 2023 also has a row for LVEF ≤35%, sinus rhythm, LBBB with QRS ≥150 ms and NYHA class II-IV on GDMT: CSP with His bundle pacing with LBBB correction or left bundle branch area pacing is reasonable if effective CRT cannot be achieved with biventricular pacing based on anatomical or functional criteria (COR 2a, LOE C-LD); her QRS of 142 ms is below that row’s 150 ms threshold, so it does not apply to her (no extra mark).^[6] ESC 2026: no RCT with patient-centred outcomes has evaluated CSP in HFrEF, and no recommendations can currently be made (1 mark).^[1]
5. ESC 2026: regular follow-up and optimization should be implemented, as CRT programming and FMT may require further optimization after implantation (1 mark).^[1]