Summary

Comprehensive guideline for managing ventricular arrhythmias (VA) and preventing sudden cardiac death (SCD), superseding the 2006 ACC/AHA/ESC document and the ICD sections of the 2008 device guideline. Covers acute VA management, ICD indications (primary and secondary prevention) across ischemic and nonischemic cardiomyopathy, channelopathies, HCM, ARVC, sarcoidosis, congenital heart disease, and special populations. Emphasizes shared decision-making, GDMT optimization before primary prevention ICD, and the role of catheter ablation for recurrent VT.

Key Recommendations

Implant ICD for secondary prevention in survivors of SCA due to VF/hemodynamically unstable VT, or sustained VT with structural heart disease, if meaningful survival >1 year is expected.
Implant primary prevention ICD in ischemic cardiomyopathy with LVEF ≤35% and NYHA II–III HF (or ≤30% with NYHA I) on GDMT ≥3 months and ≥40 days post-MI.
Implant primary prevention ICD in nonischemic cardiomyopathy with LVEF ≤35% and NYHA II–III HF on GDMT ≥3 months.
First-line acute therapy for hemodynamically unstable VT/VF is immediate direct-current cardioversion/defibrillation followed by ACLS; IV amiodarone preferred over lidocaine for shock-refractory VF/pulseless VT.
Beta blockers are first-line antiarrhythmic therapy for most VA and reduce SCD in HFrEF, post-MI, long QT syndrome (nadolol/propranolol preferred), and CPVT.
Avoid class I sodium channel blockers (flecainide, propafenone, encainide) in patients with prior MI, ischemia, or structural heart disease due to increased mortality (CAST).
Offer catheter ablation for recurrent sustained monomorphic VT in ischemic cardiomyopathy refractory to or intolerant of amiodarone (superior to escalating drug therapy per VANISH).
In HCM, implant ICD for prior SCA/sustained VT (Class I); consider for primary prevention if ≥1 major risk factor (LV wall thickness ≥30 mm, family history of HCM-SCD, unexplained syncope <6 mo, NSVT, abnormal BP response with risk modifiers).
In congenital long QT syndrome, treat with beta blockers (nadolol or propranolol); add mexiletine for LQT3 and consider left cardiac sympathetic denervation or ICD for high-risk/recurrent events.
In Brugada syndrome with spontaneous type 1 ECG plus prior SCA/syncope, implant ICD; quinidine and epicardial RVOT ablation are options for VF storm or recurrent events.
For PVC burden >15% with depressed LVEF (PVC-induced cardiomyopathy), catheter ablation can normalize LV function and is preferred when feasible.
Initiate shared decision-making at ICD implantation, generator change, and end of life, including discussion of deactivation of antitachycardia therapy in terminally ill patients.

Thresholds & Doses

Primary prevention ICD LVEF cutoff: ≤35% with NYHA II–III HF, or ≤30% with NYHA I (ischemic).
Wait ≥40 days after MI and ≥90 days after revascularization before primary prevention ICD implantation.
GDMT for HF must be optimized for ≥3 months before primary prevention ICD in NICM.
Meaningful survival expectation >1 year required for ICD candidacy.
Sustained VT defined as >30 seconds or requiring termination for hemodynamic compromise; VT rate >100 bpm (cycle length <600 ms).
VT/VF storm: ≥3 episodes of sustained VT/VF or appropriate ICD shocks within 24 hours.
Amiodarone for cardiac arrest: 300 mg IV bolus for VF/pulseless VT; 150 mg IV bolus for stable VT; then 1 mg/min × 6 h, then 0.5 mg/min × 18 h.
Lidocaine: 1–1.5 mg/kg IV bolus, repeat 0.5–0.75 mg/kg every 5–10 min (max 3 mg/kg); maintenance 1–4 mg/min.
Procainamide: load 10–17 mg/kg at 20–50 mg/min, maintenance 1–4 mg/min.
Epinephrine in cardiac arrest: 1 mg IV/IO every 3–5 minutes (standard dose; high-dose not beneficial).
Magnesium 1–2 g IV first-line for torsades de pointes; maintain serum K+ 4.5–5 mEq/L.
HCM SCD risk factor: LV wall thickness ≥30 mm; unexplained syncope within prior 6 months; family history of HCM-related SCD.
Long QT high-risk criteria: QTc >500 ms, LQT2/LQT3 genotype, female LQT2, age <40, symptom onset <10 years.
Short QT syndrome: QTc ≤340 ms with symptoms; markedly shortened QTc ≤300 ms associated with high SCD risk.
ARVC: PVCs >500/24 hours and exercise restriction to <650 MET-Hr/year (12.5 MET-Hr/week).
PVC-induced cardiomyopathy threshold: PVC burden typically >10–15% (often >20%) of total beats, or >10,000–20,000/day.
Cost-effectiveness benchmarks: high value <$50,000/QALY; intermediate $50,000–<$150,000/QALY; low ≥$150,000/QALY.
Out-of-hospital cardiac arrest overall survival ~10%; survival to discharge after in-hospital arrest ~24%; survival falls to ≤25% by 4–5 min and 0% by 10 min without intervention.

Citations

Section 6 and Figure 2 — acute management of sustained monomorphic VT and use of amiodarone/lidocaine/procainamide
Section 7.1.1–7.1.2 and Figures 3–4 — secondary and primary prevention ICD in ischemic heart disease
Section 7.2.1–7.2.2 and Figure 6 — ICD recommendations in nonischemic cardiomyopathy (including DANISH context)
Section 7.4 and Table 8 — HCM SCD risk factors and ICD indications
Section 7.9.1.1–7.9.1.3 and Figures 9, 14 — long QT, CPVT, and Brugada syndrome management
Section 5.1 and Table 7 — antiarrhythmic medication pharmacology and dosing
Section 9 — PVC-induced cardiomyopathy and catheter ablation
Sections 14–15 — terminal care, ICD deactivation, and shared decision-making