S. Adam Strickberger

Amiodarone versus implantable cardioverter-defibrillator:randomized trial in patients with nonischemicdilated cardiomyopathy and asymptomaticnonsustained ventricular tachycardia—AMIOVIRT

OBJECTIVESnThe purpose of this multicenter randomized trial was to compare total mortality during therapy with amiodarone or an implantable cardioverter-defibrillator (ICD) in patients with nonischemic dilated cardiomyopathy (NIDCM) and nonsustained ventricular tachycardia (NSVT).nnnBACKGROUNDnWhether an ICD reduces mortality more than amiodarone in patients with NIDCM and NSVT is unknown.nnnMETHODSnOne hundred three patients with NIDCM, left ventricular ejection fraction < or =0.35, and asymptomatic NSVT were randomized to receive either amiodarone or an ICD. The primary end point was total mortality. Secondary end points included arrhythmia-free survival, quality of life, and costs.nnnRESULTSnThe study was stopped when the prospective stopping rule for futility was reached. The percent of patients surviving at one year (90% vs. 96%) and three years (88% vs. 87%) in the amiodarone and ICD groups, respectively, were not statistically different (p = 0.8). Quality of life was also similar with each therapy (p = NS). There was a trend with amiodarone, as compared to the ICD, towards improved arrhythmia-free survival (p = 0.1) and lower costs during the first year of therapy (

Does the Risk-Benefit Analysis Favor the Extraction of Failed, Sterile Pacemaker and Defibrillator Leads?

8,879 US dollars vs.

Ablation of isthmus dependent atrial flutter: When to call for the next patient

22,039 US dollars, p = 0.1).nnnCONCLUSIONSnMortality and quality of life in patients with NIDCM and NSVT treated with amiodarone or an ICD are not statistically different. There is a trend towards a more beneficial cost profile and improved arrhythmia-free survival with amiodarone therapy.

Junctional Rhythms and Junctional Tachycardia

Transvenous pacemaker and defibrillator (PM‐D) lead failure is an important clinical problem. Lead extraction is routinely performed in patients with transvenous pacemaker and defibrillator (PM‐D) infections. The management of sterile PM‐D leads that have failed or are no longer required is less uniform. While extraction of excess or failed sterile PM‐D leads is often advocated, the risk of lead extraction must be weighed against the risk of abandoning these leads. There are no randomized trials comparing lead extraction with abandoning sterile leads in this setting. What then are the data that are used to advocate the extraction of excess or failed, sterile chronically implanted PM‐D leads, and are the data adequate to make this recommendation?

Amiodarone versus Implantable Defibrillator (AMIOVIRT): background, rationale, design, methods, results and implications.

Typical atrial flutter is a common reentrant atrial arrhythmia. The critical portion of the reentrant circuit is the rim of tissue between the tricuspid valve (TV) annulus and the inferior vena cava (IVC) (Fig.1).1,2 The reentrant circuit can operate in either clockwise or counterclockwise directions (Figs. 2–3). Elimination of conduction across the TV-IVC isthmus eliminates the tachycardia.3 The endpoint of ablation is to achieve bidirectional TVIVC isthmus block. Successful ablation of TV-IVC

Atrial Fibrillation Degenerates Into Ventricular Fibrillation

Junctional rhythms are electrical rhythms that originate from the atrioventricular junction. Although relatively rare, junctional rhythms encompass a wide spectrum of arrhythmias with variable clinical presentations, significance, and treatment strategies. Junctional rhythms can be grouped into four categories: (1) those that occur as a primary abnormality of the atrioventricular junction and lead to incessant or paroxysmal junctional ectopic tachycardia; (2) those that occur after cardiac surgery, mostly in infants and children; (3) those that occur secondary to autonomic, metabolic, or drug effects; and (4) those that occur as an escape rhythm in the presence of severe bradycardia. This chapter will focus on the first two categories of junctional rhythms.

PAVEing the Way for Cardiac Resynchronization Therapy

Non ischemic dilated cardiomyopathy (NIDCM) is a substrate for sudden cardiac death. Treatment with amiodarone may have a positive or neutral survival benefit. The role of ICD therapy in the primary prevention of sudden cardiac death in asymptomatic NIDCM patients is not clear. The purpose of the Amiodarone versus Implantable Defibrillator (AMIOVIRT) study was to compare total mortality, arrhythmia-free survival, quality of life and costs of therapy in patients with NIDCM, asymptomatic non-sustained ventricular tachycardia (NSVT) and left ventricular ejection fraction <or=0.35 who were randomized to therapy with amiodarone (52 patients) or an ICD (51 patients). At the first scheduled interim analysis, the previously determined stopping rule for futility was reached and the study was stopped. There was no statistically significant difference in the 1- and 3-year survival rates in the patients who received amiodarone compared with those who received an ICD (90% and 87% for amiodarone group versus 96% and 88% for ICD group; p = 0.8). There was a trend towards improved arrhythmia-free survival rates (p = 0.1), and cost of medical care (8,879 dollars vs. 22,039 dollars, p = 0.1) in the patients who were treated with amiodarone as compared to the patients who were treated with an ICD. At one year, the quality of life measures were not significantly different (p = 0.1).

Can We Predict Thromboembolic Events in Low-Risk Patients Undergoing Catheter Ablation of Atrial Fibrillation?: The Hanging CHAD*

![Figure][1] nnA 43-year-old man with paroxysmal atrial fibrillation (AF) and an implantable cardioverter defibrillator (ICD) placed for documented ventricular fibrillation (VF), presented with an ICD shock. Ventricular pre-excitation was not present. Interrogation of his ICD demonstrated AF

The role of ventricular tachycardia ablation in the reduction of implantable defibrillator shocks.

Permanent pacing and atrioventricular junction (AVJ) ablation is an effective and established therapy for atrial fibrillation with medically refractory rapid ventricular rates.1,2 The rate control achieved by AVJ ablation and right ventricular (RV) pacing comes at a price: an iatrogenic left bundle branch block with ventricular dyssynchrony. In patients with systolic dysfunction who are treated with an implantable defibrillator, RV pacing is associated with additional depression of the left ventricular ejection fraction and an increased frequency of symptomatic heart failure and adverse clinical outcomes.3,4 Cardiac resynchronization therapy (CRT) improves mortality and quality of life in patients with symptomatic heart failure in the setting of systolic dysfunction, a left bundle branch block, and sinus rhythm.5,6 However, the role of CRT in patients who undergo AVJ ablation and permanent pacemaker implantation for the treatment of chronic atrial fibrillation with medically refractory rapid ventricular rates has been obscure. In this issue of the Journal, Doshi et al. present the results of a prospective, randomized study of 184 patients with chronic atrial fibrillation who underwent AVJ ablation and were randomized to CRT or RV pacing.7 Unique to randomized CRT trials, Post AV Nodal Ablation Evaluation (PAVE) enrolled patients with abnormal as well as normal left ventricular ejection fractions. The study compared 6-minute hallway walk distance, quality of life, and left ventricular ejection fraction after AVJ ablation in 103 patients who were randomized to treatment with CRT and 81 patients who were randomized to treatment with RV pacing. Both treatment groups showed similar improvements in 6-minute hallway walk distance at 6 and 12 weeks, but by 6 months postablation, the patients treated with CRT improved to a greater degree compared with the patients treated with RV pacing (31% above baseline vs 24% above baseline, P = 0.04). Similarly, at 6 months the left ventricular ejection fraction in patients treated with CRT was significantly greater compared with patients who received RV pacing (46% vs 41%, P = 0.03). Despite these objective improvements in hallway walk distance and left ventricular ejection fraction with CRT compared with RV pacing, no significant difference in quality of life was observed. When the data were stratified, patients with a normal left ventricular ejection fraction and no heart failure had the same benefit with CRT as with RV pacing. In contrast, patients with New York Heart Association (NYHA) Class II or III heart failure symptoms at enrollment who were

Cardiac resynchronization therapy in patients with minimally symptomatic heart failure

Atrial fibrillation (AF) is the most common arrhythmia. It is associated with a decreased quality of life, increased hospitalizations, and a 2-fold increased risk of death. Perhaps most importantly, the risk of a thromboembolic (TE) event in patients with AF is increased 5-fold ([1–3][1]).