Genome-wide association of implantable cardioverter-defibrillator activation with life-threatening arrhythmias.

Objectives: To identify genetic factors that would be predictive of individuals who require an implantable cardioverter-defibrillator (ICD), we conducted a genome-wide association study among individuals with an ICD who experienced a life-threatening arrhythmia (LTA; cases) vs. those who did not over at least a 3-year period (controls).

Background: Most individuals that receive implantable cardioverter-defibrillators never experience a life-threatening arrhythmia.

Temporal stability of defibrillation thresholds with cardiac resynchronization therapy.

Background: Defibrillation thresholds (DFTs) are typically stable over time among patients with implantable cardioverter-defibrillators (ICDs). However, the impact of cardiac resynchronization therapy (CRT) on DFTs has not been studied systematically.

Objective: This study prospectively evaluated the effect of CRT and left ventricular (LV) chamber reverse remodeling on DFTs.

Gender disparity in the use of cardiac resynchronization therapy in the United States.

Background: Although several studies have shown the effectiveness of cardiac resynchronization therapy (CRT) for advanced congestive heart failure (CHF), gender differences in utilization of CRT are not known.

Methods: We used the Healthcare Cost and Utilization Project (HCUP) to study national rates for admissions due to CHF along with procedures for initial CRT implantation, including both CRT-defibrillator (CRT-D) and CRT-pacemakers (CRT-P) during the years of 2002-2004. Chi-square tests were used for comparison between number of women and men.

Site localization and characterization of pain during radiofrequency ablation of the pulmonary veins.

Background: Characteristics of radiofrequency (RF) lesions producing pain with an 8-mm catheter during pulmonary vein (PV) ablation have not been prospectively studied.

Methods: We studied 46 (30 men, age 56 +/- 10 years) patients with AF who underwent RF ablation of PVs. PV isolation was achieved by using an 8F, 8-mm Biosense ablation catheter (Biosense Webster, Diamond Bar, CA, USA) guided by intracardiac echocardiography (ICE).

Cryoablation inside the pulmonary vein after failure of radiofrequency antral isolation.

Background: Antral pulmonary vein (PV) ablation with radiofrequency (RF) energy has become widely used as a curative approach for the treatment of atrial fibrillation. In some patients, despite antral ablation, PV entry and exit conduction block (BDB) cannot be achieved with RF energy. Cryoablation inside the PV may be an effective method to achieve BDB.

Slow atrioventricular nodal reentrant arrhythmias: clinical recognition, electrophysiological characteristics, and response to radiofrequency ablation.

Background: Atrioventricular nodal reentrant tachycardia (AVNRT) is a common form of supraventricular tachycardia (SVT). Rarely, patients may present with an unusual form of atrioventricular nodal reentrant arrhythmia (AVNRA) with a cycle length greater than 600 ms. We describe the clinical presentation, electrophysiology characteristics, and response to radiofrequency ablation in a group of patients with AVNRA.

Incidence, time course, and characteristics of microbubble formation during radiofrequency ablation of pulmonary veins with an 8-mm ablation catheter.

Background: Microbubble formation during pulmonary vein (PV) radiofrequency (RF) ablation of atrial fibrillation (AF) occurs relatively frequently. Prior studies have shown that microbubble formation may be associated with an increased risk of complications. However, the incidence, time course, and temperature characteristics of microbubble formation during AF ablation with an 8-mm catheter have not been prospectively described in humans.

Frequency of atrial tachyarrhythmias following transcatheter closure of patent foramen ovale.

Background: Transcatheter closure of patent foramen ovale (PFO) in patients with a history of cryptogenic stroke is performed with increasing frequency. However, the long-term effects of these closure devices on atrial tachyarrhythmias (ATs) are not known.

Methods And Results: The study population included 71 patients [31 (44%) men, aged 54 +/- 14 years] with PFO, diagnosed by transesophageal echocardiography (TEE), and greater than or equal to 1 cryptogenic stroke (n = 70) or orthodoxia (n = 1).

Repeated dual external direct cardioversions using two simultaneous 360-J shocks for refractory atrial fibrillation are safe and effective.

Failure of cardioversion of atrial fibrillation (AF) to sinus rhythm (SR) by standard external direct current cardioversion (DCC) may be due to failure of delivery of enough defibrillating energy rather than to the true refractoriness of AF. Ninety-nine patients with persistent AF (76 male; age 63.7 +/- 0.

Efficacy and safety of sildenafil in the evaluation of pulmonary hypertension in severe heart failure.

This study sought to evaluate the utility of sildenafil in assessing pulmonary artery reactivity in left-sided cardiac failure and secondary pulmonary hypertension (PH). Fourteen consecutive patients with heart failure were studied, with oral doses of either sildenafil 25 mg (n = 8) or 50 mg (n = 6) every 8 hours for 20% decreases in pulmonary artery pressures.

Difficult cases in heart failure. Percutaneous transluminal septal myocardial ablation in the management of hypertrophic obstructive cardiomyopathy.

Hypertrophic cardiomyopathy is a complex genetic condition with a heterogeneous clinical course. Some patients remain asymptomatic throughout life while others develop one or more of the adverse clinical consequences including symptoms of congestive heart failure with exertional dyspnea and functional disability (usually with preserved left ventricular systolic function), atrial fibrillation, or sudden cardiac death. Because of this heterogenicity in the clinical presentations, management of patients with hypertrophic cardiomyopathy includes a wide range of pharmacologic therapies as well as invasive approaches.

Sildenafil and assessment of pulmonary arterial reactivity in heart failure.

Pulmonary hypertension is a daunting accompaniment of advanced heart failure. Efforts to safely and consistently lower pulmonary vascular resistance are necessary but fraught with challenges. In this report the authors explore the novel use of sildenafil, an inhibitor of phosphodiesterase-5, in tackling pulmonary hypertension in heart failure.

Use of pharmaceuticals in noninvasive cardiovascular diagnosis.

A number of pharmaceuticals are employed as diagnostic agents for cardiovascular diseases. Four groups of agents are reviewed here: 1) vasoactive substances employed as adjuncts to physical maneuvers in diagnosis of structural heart disease; 2) vasodilators used to produce heterogeneity of coronary flow; 3) sympathomimetic agents simulating the effects of exercise on the heart for the purpose of detection of coronary artery stenosis; and 4) ultrasonic contrast agents used to enhance myocardial imaging for the assessment of segmental wall motion. In the first group are amyl nitrate, a vasodilator, and methoxamine and phenylephrine, both vasopressors.