Amiodarone use after acute myocardial infarction complicated by heart failure and/or left ventricular dysfunction may be associated with excess mortality

Factors and outcomes associated with improved left ventricular systolic function in patients with cardiomyopathy

BACKGROUND

Many patients in the Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT) had a significant improvement (> 10%) in the left ventricular ejection fraction (LVEF) during the course of the study, but the factors and outcomes associated with such improvement are uncertain.

METHODS

We examined factors and rates of mortality, cause-specific mortality, and implantable cardioverter-defibrillator (ICD) shocks associated with improvement in LVEF by analyzing patients in the SCD-HeFT who were randomized to placebo or an ICD and who had an LVEF checked during follow-up.

RESULTS

During a median follow-up of 3.99 years, of 837 patients who had at least two follow-up LVEF measurements, 276 (33%) patients had > 10% improvement in LVEF and 561 (67%) patients had no significant change in LVEF. Factors significantly associated with LVEF improvement included female sex, white race, history of hypertension, a QRS duration < 120 ms, and beta-blocker use. Improvement in LVEF was associated with a significant improvement in survival. There was no significant association between improvement in LVEF and cause-specific death, but there was a significant association between improvement in LVEF and reduced risk of receiving appropriate ICD shocks.

CONCLUSIONS

About a third of patients in this analysis, who were randomized to placebo or an ICD in SCD-HeFT, had a significant improvement in LVEF during follow-up; improvement in LVEF was associated with improved survival but not with cause-specific death, and with decreased likelihood of receiving appropriate ICD shocks.

Managing Atrial Fibrillation in Patients With Heart Failure and Reduced Ejection Fraction: A Scientific Statement From the American Heart Association

Atrial fibrillation and heart failure with reduced ejection fraction are increasing in prevalence worldwide. Atrial fibrillation can precipitate and can be a consequence of heart failure with reduced ejection fraction and cardiomyopathy. Atrial fibrillation and heart failure, when present together, are associated with worse outcomes. Together, these 2 conditions increase the risk of stroke, requiring oral anticoagulation in many or left atrial appendage closure in some. Medical management for rate and rhythm control of atrial fibrillation in heart failure remain hampered by variable success, intolerance, and adverse effects. In multiple randomized clinical trials in recent years, catheter ablation for atrial fibrillation in patients with heart failure and reduced ejection fraction has shown superiority in improving survival, quality of life, and ventricular function and reducing heart failure hospitalizations compared with antiarrhythmic drugs and rate control therapies. This has resulted in a paradigm shift in management toward nonpharmacological rhythm control of atrial fibrillation in heart failure with reduced ejection fraction. The primary objective of this American Heart Association scientific statement is to review the available evidence on the epidemiology and pathophysiology of atrial fibrillation in relation to heart failure and to provide guidance on the latest advances in pharmacological and nonpharmacological management of atrial fibrillation in patients with heart failure and reduced ejection fraction. The writing committee's consensus on the implications for clinical practice, gaps in knowledge, and directions for future research are highlighted.

Patterns of amiodarone use and outcomes in clinical practice for atrial fibrillation

BACKGROUND

Amiodarone is the most effective antiarrhythmic drug (AAD) for atrial fibrillation (AF), but it has a high incidence of adverse effects.

METHODS

Using the ORBIT AF registry, patients with AF on amiodarone at enrollment, prescribed amiodarone during follow-up, or never on amiodarone were analyzed for the proportion treated with a guideline-based indication for amiodarone, the variability in amiodarone use across sites, and the outcomes (mortality, hospitalization, and stroke) among patients treated with amiodarone. Hierarchical logistic regression modeling with site-specific random intercepts compared rates of amiodarone use across 170 sites. A logistic regression model for propensity to receive amiodarone created a propensity-matched cohort. Cox proportional hazards modeling, stratified by matched pairs evaluated the association between amiodarone and outcomes.

RESULTS

Among 6,987 AF patients, 867 (12%) were on amiodarone at baseline and 451 (6%) started on incident amiodarone during the 3-year follow-up. Use of amiodarone varied among sites from 3% in the lowest tertile to 21% in the highest (p<0.0001). Among those treated, 32% had documented contraindications to other AADs or had failed another AAD in the past. Mortality, cardiovascular hospitalization, and stroke were similar among matched patients on and not on amiodarone at baseline, while incident amiodarone use in matched patients was associated with higher all-cause mortality (adjusted HR 2.06, 95% CI 1.35-3.16).

CONCLUSIONS

Use of amiodarone among AF patients in community practice is highly variable. More than 2 out of 3 patients treated with amiodarone appeared to be eligible for a different AAD.

Amiodarone is associated with adverse outcomes in patients with sustained ventricular arrhythmias upgraded to cardiac resynchronization therapy-defibrillators

INTRODUCTION

Amiodarone reduces recurrent ventricular tachyarrhythmias (VTA) but may worsen cardiovascular outcomes in heart failure (HF) patients. Cardiac resynchronization therapy (CRT) may also be antiarrhythmic. When patients with prior sustained VTA are upgraded to CRT defibrillators (CRT-D) from conventional implantable cardioverter-defibrillators (ICDs), should concomitant amiodarone be continued or is CRT's antiarrhythmic potential sufficient?

METHODS AND RESULTS

We identified 67 patients from a prospective CRT registry with spontaneous sustained VTA, New York Heart Association (NYHA) II-IV HF, and left bundle-branch block (LBBB) who were upgraded to CRT defibrillators from conventional ICDs. We compared changes in QRS duration and left ventricular ejection fraction (LVEF) pre- and post-CRT, time to death, transplant or ventricular assist device (VAD), and time to recurrent VTA therapies between 37 patients continuing amiodarone therapy and 30 amiodarone-naïve patients. Amiodarone-treated patients had worse renal function and a higher prevalence of prior VTA storm compared with amiodarone-naïve patients. After CRT, amiodarone-treated patients demonstrated less QRS narrowing (8 vs 20 ms; P = 0.021) and less LVEF improvement (-2.7 vs +5.2%; P = 0.006). Over 29 months, 31 (47%) patients died and 13 (20%) received transplant or VAD. Risk of death, transplant, or VAD was greater in amiodarone-treated than -naïve patients (corrected hazard ratio [HR], 2.14; 95% confidence interval [CI], 1.12-4.11; P = 0.022). Appropriate CRT-D therapies occurred in 37 (55%) patients; amiodarone use was not associated time to first therapy (HR, 1.13; 95% CI, 0.59-2.16; P = 0.72).

CONCLUSION

In patients with sustained VTA and LBBB upgraded from conventional ICDs to CRT defibrillators, concomitant amiodarone use is associated with less QRS narrowing, less LVEF improvement, greater risk of death, transplant, or VAD, and similar risk of recurrent VTA.

Single-photon emission computed tomographic-multidetector computed tomographic fusion image integration: a potential aid to left ventricular substrate ablation

AIMS

To illustrate the feasibility of ventricular tachycardia (VT) ablation assisted by single photon emission computed tomography (SPECT)-multidetector (MDCT) computed tomography 'fusion' image guidance.

METHODS AND RESULTS

A patient with ischaemic cardiomyopathy and recurrent VT underwent catheter ablation. Prior to the procedure, SPECT and MDCT had been obtained. A combined ('fusion') image was created, and this image was registered to the operative field using a commercial catheter navigation system. There was a close anatomic and electrophysiological correspondence between the left ventricular electroanatomic map obtained in the operating theatre and the fusion image.

CONCLUSION

If accuracy of this technique can be confirmed, fusion image guidance may offer a significant value during catheter ablation of VT, including improved substrate detail and procedure abbreviation.

Use of evidence-based cardiac prevention therapy among outpatients with atrial fibrillation

BACKGROUND

Patients with atrial fibrillation often have cardiovascular risk factors or known comorbid disease, yet the use of evidence-based primary and secondary prevention cardiac therapy among atrial fibrillation outpatients is unknown.

METHODS

Using baseline data collected between June 2010 and August 2011 from 174 sites participating in ORBIT-AF, a US national registry of patients with atrial fibrillation coordinated from Durham, NC, we examined professional guideline-recommended evidence-based therapy use for cardiovascular comorbid conditions and risk factors. Multivariable logistic regression was used to identify factors associated with receipt of all indicated evidence-based therapy.

RESULTS

Among 10,096 enrolled patients, 93.5% were eligible for one or more evidence-based therapies. Among those eligible, 46.6% received all indicated therapies: 62.3% received an antiplatelet agent, 72.3% received a beta-blocker, 59.5% received an angiotensin-converting enzyme or angiotensin receptor blocker, 15.3% received an aldosterone antagonist, 65.7% received a statin, and 58.8% received an implantable cardioverter-defibrillator. A minority of patients with coronary artery disease, diabetes mellitus, heart failure, and peripheral vascular disease received all indicated therapies (25.1%, 43.2%, 42.5%, and 43.4%, respectively). A total of 52.4% of patients had controlled hypertension and 74.6% of patients with hyperlipidemia received a statin. Factors associated with nonreceipt of all indicated therapies included frailty, comorbid illness, geographic region, and antiarrhythmic drug therapy.

CONCLUSIONS

The majority of eligible atrial fibrillation outpatients did not receive all guideline-recommended therapies for cardiovascular comorbid conditions and risk factors. This represents a potential opportunity to improve atrial fibrillation patients' quality of care and outcomes.

Anti-Arrhythmic Agents in the Treatment of Atrial Fibrillation

Although atrial fibrillation (AF) is the most common sustained arrhythmia seen during daily cardiovascular physician practice, its management remained a challenge for cardiology physician as there was no single anti-arrhythmic agents proved to be effective in converting atrial fibrillation and kept its effectiveness in maintaining sinus rhythm over long term. Moreover all the anti-arrhythmic agents that are used in treatment of AF were potentially pro-arrhythmic especially in patients with coronary artery disease and structurally abnormal heart. Some of these drugs also have serious non cardiac side effects that limit its long term use in the management of atrial fibrillation. Several new and investigational anti-arrhythmic agents are emerging but data supporting their effectiveness and safety are still limited. In this systematic review we examine the efficacy and safety of these medications supported by the major published randomized trials, meta-analyses and review articles and conclude with a summary of guidelines recommendations.

Thyroid hormone, amiodarone therapy, and prognosis in left ventricular systolic dysfunction

BACKGROUND

Amiodarone protects patients with left ventricular systolic dysfunction (LVSD) against serious arrhythmias, but it also has numerous side effects on non-cardiac organs, such as the thyroid. Indeed, amiodarone may inhibit the peripheral conversion of T₄ into T₃. Pathologically reduced serum levels of T₃ - the so-called "low T₃ syndrome" (LOWT3) - increase mortality in patients with LVSD and not on amiodarone.

AIM

The aim of the study was to examine the relationship between thyroid hormone status, amiodarone therapy, and outcome in a population with LVSD. MATERIAL/ SUBJECTS AND METHODS: A total of 2344 patients with LVSD and free of overt hyper- and hypothyroidism were enrolled. The population was divided into 4 groups: group 1 (LOWT3 and amiodarone therapy, no.=126), group 2 (isolated amiodarone therapy, no.=74), group 3 (isolated LOWT3, no.=682), group 4 (controls, no.=1462).

RESULTS

Kaplan-Meier curves showed, after a mean follow-up of 31 months, increased total and cardiac mortality in groups 1 (30% and 20%, respectively), 2 (23%, 11%), and 3 (22%, 12%) compared to group 4 (total mortality log-rank 82.8, p<0.0001; cardiac mortality log-rank 63.1, p<0.0001). At Cox analysis, adjusted for several clinical variables, survival was reduced in groups 1 and 3 compared to group 4. Group 2 had a similar mortality to group 4, although the number of patients was too limited to accurately assess the effect of amiodarone on long-term prognosis.

CONCLUSIONS

LOWT3 exerts an adverse impact on prognosis in LVSD, which is not influenced by concomitant amiodarone therapy.

Antiarrhythmic drug therapy for sustained ventricular arrhythmias complicating acute myocardial infarction

OBJECTIVE

Few data exist to guide antiarrhythmic drug therapy for sustained ventricular tachycardia/ventricular fibrillation after acute myocardial infarction. The objective of this analysis was to describe the survival of patients with sustained ventricular tachycardia/ventricular fibrillation after myocardial infarction according to antiarrhythmic drug treatment.

DESIGN AND SETTING

We conducted a retrospective analysis of ST-segment elevation myocardial infarction patients with sustained ventricular tachycardia/ventricular fibrillation in Global Use of Strategies to Open Occluded Coronary Arteries in Acute Coronary Syndromes (GUSTO) IIB and GUSTO III and compared all-cause death in patients receiving amiodarone, lidocaine, or no antiarrhythmic. We used Cox proportional-hazards modeling and inverse weighted estimators to adjust for baseline characteristics, β-blocker use, and propensity to receive antiarrhythmics. Due to nonproportional hazards for death in early follow-up (0-3 hrs after sustained ventricular tachycardia/ventricular fibrillation) compared with later follow-up (>3 hrs), we analyzed all-cause mortality using time-specific hazards.

PATIENTS AND INTERVENTIONS

Among 19,190 acute myocardial infarction patients, 1,126 (5.9%) developed sustained ventricular tachycardia/ventricular fibrillation and met the inclusion criteria. Patients received lidocaine (n = 664, 59.0%), amiodarone (n = 50, 4.4%), both (n = 110, 9.8%), or no antiarrhythmic (n = 302, 26.8%).

RESULTS

In the first 3 hrs after ventricular tachycardia/ventricular fibrillation, amiodarone (adjusted hazard ratio 0.39, 95% confidence interval 0.21-0.71) and lidocaine (adjusted hazard ratio 0.72, 95% confidence interval 0.53-0.96) were associated with a lower hazard of death-likely evidence of survivor bias. Among patients who survived 3 hrs, amiodarone was associated with increased mortality at 30 days (adjusted hazard ratio 1.71, 95% confidence interval 1.02-2.86) and 6 months (adjusted hazard ratio 1.96, 95% confidence interval 1.21-3.16), but lidocaine was not at 30 days (adjusted hazard ratio 1.19, 95% confidence interval 0.77-1.82) or 6 months (adjusted hazard ratio 1.10, 95% confidence interval 0.73-1.66).

CONCLUSION

Among patients with acute myocardial infarction complicated by sustained ventricular tachycardia/ventricular fibrillation who survive 3 hrs, amiodarone, but not lidocaine, is associated with an increased risk of death, reinforcing the need for randomized trials in this population.

Benefits and risks of long-term amiodarone therapy for persistent atrial fibrillation: a meta-analysis

OBJECTIVE

To assess whether amiodarone, as part of a strategy to achieve sinus rhythm, is safe and effective compared with a placebo or rate control drug in patients with persistent atrial fibrillation (AF) of more than 30 days' duration.

METHODS

Randomized controlled trials comparing amiodarone with a placebo or rate control drug were identified through the EMBASE (January 1, 1988, to October 18, 2008), MEDLINE (January 1, 1966, to October 18, 2008), and Cochrane Controlled Trials Register (second issue 2008) databases with no language restrictions.

RESULTS

Twelve randomized controlled trials that involved a total of 5060 patients with persistent AF were considered. Amiodarone was more effective than a placebo or rate control drug in achieving sinus rhythm (21.3 vs 9.2 per 100 patient-years in sinus rhythm; relative risk [RR], 3.2; 95% confidence interval [CI], 1.9-5.5), and its use was not associated with an increased risk of long-term mortality (4.7 vs 3.9 per 100 patient-years; RR, 0.95; 95% CI, 0.8-1.1; P=.51; I2=0%). Cessation of amiodarone therapy because of intolerable adverse effects was more common compared with a placebo or rate control drug (10.7 vs 1.9 per 100 patient-years; RR, 3.0; 95% CI, 1.4-6.2; P<.001; I2=70%), but amiodarone was not associated with an increased incidence of hospitalizations (RR, 1.1; 95% CI, 0.6-2.1; P=.77; I2=90%).

CONCLUSION

Amiodarone, as part of a strategy to achieve and maintain sinus rhythm, appears to be safe and effective in patients with persistent AF. However, some patients may not tolerate the adverse effects of this agent.

Benefits and risks of long-term amiodarone therapy for persistent atrial fibrillation: a meta-analysis

OBJECTIVE

To assess whether amiodarone, as part of a strategy to achieve sinus rhythm, is safe and effective compared with a placebo or rate control drug in patients with persistent atrial fibrillation (AF) of more than 30 days' duration.

METHODS

Randomized controlled trials comparing amiodarone with a placebo or rate control drug were identified through the EMBASE (January 1, 1988, to October 18, 2008), MEDLINE (January 1, 1966, to October 18, 2008), and Cochrane Controlled Trials Register (second issue 2008) databases with no language restrictions.

RESULTS

Twelve randomized controlled trials that involved a total of 5060 patients with persistent AF were considered. Amiodarone was more effective than a placebo or rate control drug in achieving sinus rhythm (21.3 vs 9.2 per 100 patient-years in sinus rhythm; relative risk [RR], 3.2; 95% confidence interval [CI], 1.9-5.5), and its use was not associated with an increased risk of long-term mortality (4.7 vs 3.9 per 100 patient-years; RR, 0.95; 95% CI, 0.8-1.1; P=.51; I2=0%). Cessation of amiodarone therapy because of intolerable adverse effects was more common compared with a placebo or rate control drug (10.7 vs 1.9 per 100 patient-years; RR, 3.0; 95% CI, 1.4-6.2; P<.001; I2=70%), but amiodarone was not associated with an increased incidence of hospitalizations (RR, 1.1; 95% CI, 0.6-2.1; P=.77; I2=90%).

CONCLUSION

Amiodarone, as part of a strategy to achieve and maintain sinus rhythm, appears to be safe and effective in patients with persistent AF. However, some patients may not tolerate the adverse effects of this agent.