Relationship of frequent postinfarction premature ventricular complexes to the reentry circuit of scar-related ventricular tachycardia.

Background: Postinfarction reentrant ventricular tachycardia (VT) is usually scar-related. However, the sites of origin of premature ventricular complexes (PVCs) in the setting of healed myocardial infarction have not been well characterized.

Objective: The purpose of this study was to determine the site of origin of frequent PVCs in postinfarction patients with VT and to determine the relationship to VT exit sites.

Spatial resolution of pace mapping of idiopathic ventricular tachycardia/ectopy originating in the right ventricular outflow tract.

Background: Pace mapping has been used to identify the site of origin of focal ventricular arrhythmias. The spatial resolution of pace mapping has not been adequately quantified using currently available three-dimensional mapping systems.

Objective: The purpose of this study was to determine the spatial resolution of pace mapping in patients with idiopathic ventricular tachycardia or premature ventricular contractions originating in the right ventricular outflow tract.

Inducibility of paroxysmal atrial fibrillation by isoproterenol and its relation to the mode of onset of atrial fibrillation.

Background: Isoproterenol has been used to assess inducibility during catheter ablation for paroxysmal PAF. However, no studies have determined the sensitivity and specificity of isoproterenol for the induction of AF. It also is not clear whether isoproterenol is equally effective in inducing AF in the clinical subtypes of vagotonic, adrenergic, and random AF.

Temporal stability of the location of the esophagus in patients undergoing a repeat left atrial ablation procedure for atrial fibrillation or flutter.

Background: The esophagus may be mobile during a left atrial (LA) ablation procedure for atrial fibrillation (AF).

Objective: The goal of the study was to determine whether the location of the esophagus is stable in patients undergoing a repeat LA ablation procedure.

Methods: Forty-two patients underwent repeat LA ablation a mean of 7 +/- 2 months after the initial procedure.

Postoperative atrial fibrillation.

Atrial fibrillation is a common arrhythmia after cardiac surgery. It is associated with an increase in morbidity, length of hospital stay, and mortality. Patients who are at higher risk of postoperative atrial fibrillation should receive prophylactic treatment.

Mechanism of recurrence after radiofrequency catheter ablation of atrial fibrillation guided by complex fractionated atrial electrograms.

Background: A better understanding of the mechanisms of recurrent atrial fibrillation (AF) after radiofrequency ablation of complex, fractionated atrial electrograms (CFAEs) may be helpful for refining AF ablation strategies.

Methods And Results: Electrogram-guided ablation (EGA) was repeated in 30 consecutive patients (mean age = 59 +/- 8 years) for recurrent paroxysmal AF, 10 +/- 4 months after the first ablation. During the first procedure, CFAEs were targeted without isolating all pulmonary veins (PVs).

Cardiac arrhythmias: management of atrial fibrillation in the critically ill patient.

This article reviews the most relevant information for the hospitalist or intensivist managing patients who have atrial fibrillation (AF) in the acute or critical care setting. Emphasis is placed on clinically useful information, and evidence-based strategies for managing acute and chronic AF.

Atrial tachycardia after circumferential pulmonary vein ablation of atrial fibrillation: mechanistic insights, results of catheter ablation, and risk factors for recurrence.

Objectives: The aim of this study was to determine the mechanism of atrial tachycardia (AT) that occurs after ablation of atrial fibrillation (AF).

Background: Patients who undergo catheter ablation of AF may develop AT during follow-up.

Methods: Seventy-eight patients underwent an ablation procedure for AT after circumferential pulmonary vein ablation (CPVA) for AF.

Conversion of atrial fibrillation to sinus rhythm during treatment with intravenous esmolol or diltiazem: a prospective, randomized comparison.

Prior studies have suggested that intravenous diltiazem reduces the probability of spontaneous conversion of atrial fibrillation (AF) to sinus rhythm in the electrophysiology laboratory and in patients with postoperative AF. Whether diltiazem exerts the same effect in patients presenting to the emergency department (ED) with spontaneous AF is unclear. Fifty patients presenting to the ED with new-onset or paroxysmal AF and a rapid ventricular rate (>100 beats per minute) were randomly assigned to receive intravenous diltiazem or esmolol during the first 24 hours of presentation.

The involvement of IL-10, IL-6, IFN-gamma, TNF-alpha and TGF-beta gene polymorphisms among Turkish lung cancer patients.

Several genes encoding different cytokines may play crucial roles in host susceptibility to lung cancer, since cytokine production capacity varies among individuals and depends on cytokine gene polymorphisms. The association between cytokine gene polymorphisms with primary lung carcinoma was investigated. DNA samples were obtained from a Turkish population of 44 patients with primary lung cancer, and 59 healthy control subjects.

Radiofrequency ablation of frequent, idiopathic premature ventricular complexes: comparison with a control group without intervention.

Background: Idiopathic premature ventricular complexes (PVCs) usually are considered benign, even when frequent. However, case reports have demonstrated a possible link between frequent PVCs and left ventricular (LV) dysfunction. In addition, frequent PVCs recently were demonstrated to be associated with increased LV dimensions and cardiomyopathy.

IL-10 and IL-6 gene polymorphisms as potential host susceptibility factors in Brucellosis.

Several genes encoding for different cytokines may play crucial roles in host susceptibility to Brucellosis, since the cytokine production capacity varies among individuals and depends on the cytokine gene polymorphism. The association of the cytokine gene polymorphisms with the development of Brucellosis was investigated in this study. DNA samples were obtained from a Turkish population of 40 patients with Brucellosis, and 50 healthy control subjects.

Utility of atrial and ventricular cycle length variability in determining the mechanism of paroxysmal supraventricular tachycardia.

Introduction: No prior studies have systematically investigated the diagnostic value of cycle length (CL) variability in differentiating the mechanism of paroxysmal supraventricular tachycardia (PSVT).

Methods And Results: We studied 173 consecutive patients with PSVT; 86 typical atrioventricular nodal reentrant tachycardia (AVNRT), 11 atypical AVNRT, 47 orthodromic reciprocating tachycardia (ORT), and 29 with atrial tachycardia (AT). Two consecutive atrial cycles that displayed the most CL variability were selected for analysis.

Radiofrequency catheter ablation of chronic atrial fibrillation guided by complex electrograms.

Background: Radiofrequency catheter ablation of atrial fibrillation (AF) guided by complex fractionated atrial electrograms has been reported to eliminate AF in a large proportion of patients. However, only a small number of patients with chronic AF have been included in previous studies.

Methods And Results: In 100 patients (mean age, 57+/-11 years) with chronic AF, radiofrequency ablation was performed to target complex fractionated atrial electrograms at the pulmonary vein ostial and antral areas, various regions of the left atrium, and the coronary sinus until AF terminated or all identified complex fractionated atrial electrograms were eliminated.

Role of Purkinje fibers in post-infarction ventricular tachycardia.

Objectives: The objective of this study was to assess the role of Purkinje fibers in monomorphic, post-infarction ventricular tachycardia (VT).

Background: Ventricular fibrillation and polymorphic VT in the setting of acute myocardial infarction (MI) may be triggered by ectopy arising from Purkinje fibers.

Methods: From among a group of 81 consecutive patients with post-infarction monomorphic VT referred for catheter ablation, 9 patients were identified in whom the clinical VT had a QRS duration < or =145 ms.

Circulating ICAM-1 and VCAM-1 levels in patients with obstructive sleep apnea syndrome.

Background: Obstructive sleep apnea syndrome (OSAS)-induced hypoxic stress modulates circulating inflammatory mediators causing accelerated atherogenesis.

Objectives: We hypothesized that OSAS-induced hypoxia might result in cardiovascular disease due to increased expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) on the endothelial surface.

Methods: Thirty-nine subjects with moderate-to-severe OSAS and 34 non-apneic controls matched for age, gender, body mass index (BMI), smoking history, and cardiovascular disease were included in this prospective study.

Interleukin-10 (IL-10) gene polymorphism as a potential host susceptibility factor in tuberculosis.

Several genes encoding for different cytokines may play crucial roles in host susceptibility to tuberculosis (TB), since the cytokine production capacity varies among individuals and depends on the cytokine gene polymorphism. The association of the cytokine gene polymorphisms with the development of TB was investigated in this study. DNA samples were obtained from a Turkish population of 81 patients with the different clinical forms of TB, and 50 healthy control subjects.

Risk of thromboembolic events after percutaneous left atrial radiofrequency ablation of atrial fibrillation.

Background: In patients with atrial fibrillation (AF), the risk of thromboembolic events (TEs) is variable and is influenced by the presence and number of comorbid conditions. The effect of percutaneous left atrial radiofrequency ablation (LARFA) of AF on the risk of TEs is unclear.

Methods And Results: LARFA was performed in 755 consecutive patients with paroxysmal (n = 490) or chronic (n = 265) AF.