REVIEW URRENT C OPINION
Ventricular arrhythmias in patients with heart failure secondary to reduced ejection fraction: a current perspective Girish M. Nair, Pablo B. Nery, Calum J. Redpath, and David H. Birnie
Purpose of review To review the management of ventricular arrhythmias in patients with heart failure secondary to reduced ejection fraction (HFrEF). Recent findings Recurrent ventricular arrhythmias and automatic implantable cardioverter defibrillator (AICD) shocks are responsible for significant mortality and morbidity in patients with HFrEF. Antiarrhythmic drugs and catheter ablation are the main treatment options. Frequent premature ventricular contractions (PVCs; >10 000–20 000/24-h period) are being recognized as a cause of cardiomyopathy and suboptimal response to cardiac resynchronization therapy (CRT). Patients with ventricular assist devices (VADs) have frequent ventricular tachyarrhythmias resulting in increased morbidity and mortality. Such patients may need continuation of active ICD therapy and adjunctive catheter ablation. Summary There is a pressing need to develop new antiarrhythmic drugs to treat patients with recurrent AICD shocks. The effectiveness of catheter ablation as first-line therapy for preventing ventricular arrhythmias and recurrent AICD shocks needs to be directly compared with amiodarone. Ventricular tachyarrhythmias are common in CRT patients and patients with VADs. Frequent PVCs may result in a reversible form of HFrEF. Keywords heart failure with reduced ejection fraction, management, ventricular tachyarrhythmia
INTRODUCTION Patients with congestive heart failure (CHF) and reduced ejection fraction (HFrEF) have an increased burden of ventricular tachyarrhythmias such as ventricular tachycardia and ventricular fibrillation. Patients with ventricular tachyarrhythmias are at high risk of mortality from sudden death and progressive CHF [1 ]. The risk of sudden death has been reduced by aggressive risk factor modification and the use of therapies slowing progression of heart failure, regardless of the cause of HFrEF [2–4]. Automatic implantable cardioverter defibrillator (AICD) and cardiac resynchronization therapy (CRT) have further reduced the risk of sudden cardiac death and heart failure-related mortality [5–7,8 ]. Despite tremendous advances in the management of HFrEF over the past decade, CHF continues to be a leading cause of cardiac mortality and morbidity. &
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www.co-cardiology.com
VENTRICULAR ARRHYTHMIAS IN PATIENTS WITH HEART FAILURE AND AUTOMATIC IMPLANTABLE CARDIOVERTER DEFIBRILLATOR The use of AICD therapy for prevention of sudden cardiac death in patients with HFrEF has increased exponentially over the past decade and has resulted in a large population of AICD patients [9]. Heart failure and arrhythmia physicians have to deal with Division of Cardiology, University of Ottawa Heart Institute, Ottawa, Ontario, Canada Correspondence to Dr Girish M. Nair, MBBS, MSc, FRCPC, Associate Professor/Staff Cardiologist, Arrhythmia Service, Division of Cardiology, Room# H1285-B, University of Ottawa Heart Institute, 40 Ruskin Avenue, Ottawa, ON K1Y 4W7, Canada. Tel: +1 613 761 4820; e-mail: [email protected] Curr Opin Cardiol 2014, 29:152–159 DOI:10.1097/HCO.0000000000000035 Volume 29 Number 2 March 2014
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Ventricular arrhythmias in patients with heart failure Nair et al.
KEY POINTS
anti-tachycardia pacing (ATP) to terminate a proportion of ventricular tachycardia events [17,18 ,19 ]. Despite optimal programming of AICDs, shocks are still an important cause of cardiovascular mortality and morbidity in patients with HFrEF. Even though AICDs are capable of preventing sudden cardiac death by terminating ventricular tachyarrhythmias, they are not capable of reducing the incidence of ventricular tachyarrhythmias in patients with HFrEF. Antiarrhythmic drugs (AADs) and catheter ablation are the two main treatment options in HFrEF patients with frequent ventricular tachyarrhythmias and AICD shocks. &&
Ventricular arrhythmias in patients with HFrEF resulting in recurrent AICD shocks will be an important problem facing arrhythmia specialists and heart failure doctors. AADs and catheter ablation are the mainstay of treatment and management. New AADs with improved safety and efficacy profile need to be developed. The effectiveness of catheter ablation in reducing recurrent ventricular tachyarrhythmias and AICD shocks needs to be compared directly with amiodarone in well-controlled clinical trials. PVC suppression using AAD or catheter ablation has a role in the management of CRT nonresponders and patients with PVC-induced cardiomyopathy. Patients with ventricular assist devices have a high burden of ventricular tachyarrhythmias resulting in significant morbidity and mortality. They will need ongoing AICD therapy along with adjunctive AAD and/or catheter ablation.
frequent AICD shocks in patients with HFrEF. Data from large randomized AICD trials have shown that, by 4 years after implantation, 30–35% of patients have experienced at least one shock [8 ,10–13]. Patients receiving AICD shocks are likely to have a higher rate of recurrent ventricular tachyarrhythmias and, in 10–20% of cases, the initial presentation is in the form of an electrical storm (3 episodes of ventricular tachyarrhythmias in a 24-h period). Electrical storm is associated with poor prognosis and results in a two to three-fold increase in all-cause and cardiac mortality. However, it is as yet unclear whether frequent AICD shocks have a causal role in the increase in cardiovascular mortality. It is possible that ventricular tachyarrhythmias resulting in frequent implantable cardioverter defibrillator (ICD) shocks may be the result of progression of the underlying cardiomyopathy, which is the actual cause of increased cardiovascular mortality in such patients [12,14,15 ]. In the early days after AICD use for prophylaxis against sudden cardiac death, it was apparent that, in some instances, shocks (both appropriate and inappropriate) could be avoided by optimal programming [16]. Subsequent trials have demonstrated that optimal AICD programming with use of appropriate antitachycardia pacing and shock delivery algorithms substantially reduced the incidence of shocks. Optimal AICD programming was shown to reduce shocks by using longer ventricular tachyarrhythmia detection intervals and &&
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ANTIARRHYTHMIC DRUG THERAPY FOR PREVENTION OF VENTRICULAR ARRHYTHMIAS IN AUTOMATIC IMPLANTABLE CARDIOVERTER DEFIBRILLATOR PATIENTS The risk of increased cardiovascular mortality associated with proarrhythmia in AAD trials such as the Cardiac Arrhythmia Suppression Trial (CAST) resulted in a decreasing trend in AAD use for treatment of ventricular tachyarrhythmias [20,21]. The advent of AICDs for treatment of ventricular tachyarrhythmias and sudden cardiac death prevention in HFrEF patients has resulted in a resurgence of AAD use to treat recurrent AICD shocks. b-Blockers, sotalol, azimilide, dofetilide, and amiodarone have been evaluated in clinical trials as adjunctive therapy to reduce ventricular tachyarrhythmias and shocks in AICD patients. Sotalol, a bblocker with class III AAD action, was the first AAD evaluated in a clinical trial for AICD shock prevention [22]. Azimilide, a selective blocker of IKs and IKr potassium currents, was evaluated in the Shock Inhibition Evaluation with Azimilide (SHIELD) trial. This placebo-controlled randomized trial tested the efficacy of azimilide in preventing recurrent AICD shocks in patients with HFrEF (
Ventricular arrhythmias in patients with heart failure secondary to reduced ejection fraction: a current perspective Girish M. Nair, Pablo B. Nery, Calum J. Redpath, and David H. Birnie
Purpose of review To review the management of ventricular arrhythmias in patients with heart failure secondary to reduced ejection fraction (HFrEF). Recent findings Recurrent ventricular arrhythmias and automatic implantable cardioverter defibrillator (AICD) shocks are responsible for significant mortality and morbidity in patients with HFrEF. Antiarrhythmic drugs and catheter ablation are the main treatment options. Frequent premature ventricular contractions (PVCs; >10 000–20 000/24-h period) are being recognized as a cause of cardiomyopathy and suboptimal response to cardiac resynchronization therapy (CRT). Patients with ventricular assist devices (VADs) have frequent ventricular tachyarrhythmias resulting in increased morbidity and mortality. Such patients may need continuation of active ICD therapy and adjunctive catheter ablation. Summary There is a pressing need to develop new antiarrhythmic drugs to treat patients with recurrent AICD shocks. The effectiveness of catheter ablation as first-line therapy for preventing ventricular arrhythmias and recurrent AICD shocks needs to be directly compared with amiodarone. Ventricular tachyarrhythmias are common in CRT patients and patients with VADs. Frequent PVCs may result in a reversible form of HFrEF. Keywords heart failure with reduced ejection fraction, management, ventricular tachyarrhythmia
INTRODUCTION Patients with congestive heart failure (CHF) and reduced ejection fraction (HFrEF) have an increased burden of ventricular tachyarrhythmias such as ventricular tachycardia and ventricular fibrillation. Patients with ventricular tachyarrhythmias are at high risk of mortality from sudden death and progressive CHF [1 ]. The risk of sudden death has been reduced by aggressive risk factor modification and the use of therapies slowing progression of heart failure, regardless of the cause of HFrEF [2–4]. Automatic implantable cardioverter defibrillator (AICD) and cardiac resynchronization therapy (CRT) have further reduced the risk of sudden cardiac death and heart failure-related mortality [5–7,8 ]. Despite tremendous advances in the management of HFrEF over the past decade, CHF continues to be a leading cause of cardiac mortality and morbidity. &
&&
www.co-cardiology.com
VENTRICULAR ARRHYTHMIAS IN PATIENTS WITH HEART FAILURE AND AUTOMATIC IMPLANTABLE CARDIOVERTER DEFIBRILLATOR The use of AICD therapy for prevention of sudden cardiac death in patients with HFrEF has increased exponentially over the past decade and has resulted in a large population of AICD patients [9]. Heart failure and arrhythmia physicians have to deal with Division of Cardiology, University of Ottawa Heart Institute, Ottawa, Ontario, Canada Correspondence to Dr Girish M. Nair, MBBS, MSc, FRCPC, Associate Professor/Staff Cardiologist, Arrhythmia Service, Division of Cardiology, Room# H1285-B, University of Ottawa Heart Institute, 40 Ruskin Avenue, Ottawa, ON K1Y 4W7, Canada. Tel: +1 613 761 4820; e-mail: [email protected] Curr Opin Cardiol 2014, 29:152–159 DOI:10.1097/HCO.0000000000000035 Volume 29 Number 2 March 2014
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Ventricular arrhythmias in patients with heart failure Nair et al.
KEY POINTS
anti-tachycardia pacing (ATP) to terminate a proportion of ventricular tachycardia events [17,18 ,19 ]. Despite optimal programming of AICDs, shocks are still an important cause of cardiovascular mortality and morbidity in patients with HFrEF. Even though AICDs are capable of preventing sudden cardiac death by terminating ventricular tachyarrhythmias, they are not capable of reducing the incidence of ventricular tachyarrhythmias in patients with HFrEF. Antiarrhythmic drugs (AADs) and catheter ablation are the two main treatment options in HFrEF patients with frequent ventricular tachyarrhythmias and AICD shocks. &&
Ventricular arrhythmias in patients with HFrEF resulting in recurrent AICD shocks will be an important problem facing arrhythmia specialists and heart failure doctors. AADs and catheter ablation are the mainstay of treatment and management. New AADs with improved safety and efficacy profile need to be developed. The effectiveness of catheter ablation in reducing recurrent ventricular tachyarrhythmias and AICD shocks needs to be compared directly with amiodarone in well-controlled clinical trials. PVC suppression using AAD or catheter ablation has a role in the management of CRT nonresponders and patients with PVC-induced cardiomyopathy. Patients with ventricular assist devices have a high burden of ventricular tachyarrhythmias resulting in significant morbidity and mortality. They will need ongoing AICD therapy along with adjunctive AAD and/or catheter ablation.
frequent AICD shocks in patients with HFrEF. Data from large randomized AICD trials have shown that, by 4 years after implantation, 30–35% of patients have experienced at least one shock [8 ,10–13]. Patients receiving AICD shocks are likely to have a higher rate of recurrent ventricular tachyarrhythmias and, in 10–20% of cases, the initial presentation is in the form of an electrical storm (3 episodes of ventricular tachyarrhythmias in a 24-h period). Electrical storm is associated with poor prognosis and results in a two to three-fold increase in all-cause and cardiac mortality. However, it is as yet unclear whether frequent AICD shocks have a causal role in the increase in cardiovascular mortality. It is possible that ventricular tachyarrhythmias resulting in frequent implantable cardioverter defibrillator (ICD) shocks may be the result of progression of the underlying cardiomyopathy, which is the actual cause of increased cardiovascular mortality in such patients [12,14,15 ]. In the early days after AICD use for prophylaxis against sudden cardiac death, it was apparent that, in some instances, shocks (both appropriate and inappropriate) could be avoided by optimal programming [16]. Subsequent trials have demonstrated that optimal AICD programming with use of appropriate antitachycardia pacing and shock delivery algorithms substantially reduced the incidence of shocks. Optimal AICD programming was shown to reduce shocks by using longer ventricular tachyarrhythmia detection intervals and &&
&&
&&
ANTIARRHYTHMIC DRUG THERAPY FOR PREVENTION OF VENTRICULAR ARRHYTHMIAS IN AUTOMATIC IMPLANTABLE CARDIOVERTER DEFIBRILLATOR PATIENTS The risk of increased cardiovascular mortality associated with proarrhythmia in AAD trials such as the Cardiac Arrhythmia Suppression Trial (CAST) resulted in a decreasing trend in AAD use for treatment of ventricular tachyarrhythmias [20,21]. The advent of AICDs for treatment of ventricular tachyarrhythmias and sudden cardiac death prevention in HFrEF patients has resulted in a resurgence of AAD use to treat recurrent AICD shocks. b-Blockers, sotalol, azimilide, dofetilide, and amiodarone have been evaluated in clinical trials as adjunctive therapy to reduce ventricular tachyarrhythmias and shocks in AICD patients. Sotalol, a bblocker with class III AAD action, was the first AAD evaluated in a clinical trial for AICD shock prevention [22]. Azimilide, a selective blocker of IKs and IKr potassium currents, was evaluated in the Shock Inhibition Evaluation with Azimilide (SHIELD) trial. This placebo-controlled randomized trial tested the efficacy of azimilide in preventing recurrent AICD shocks in patients with HFrEF (
