Aman Chugh

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.

Effect of catheter ablation on progression of paroxysmal atrial fibrillation.

Ablation and Progression of Atrial Fibrillation. Objective: The objective was to determine the effect of radiofrequency catheter ablation (RFA) on progression of paroxysmal atrial fibrillation (AF).

Clinical Value of Noninducibility by High‐Dose Isoproterenol Versus Rapid Atrial Pacing After Catheter Ablation of Paroxysmal Atrial Fibrillation

Noninducibility by High‐Dose Isoproterenol.u2002Objective: To determine the relative clinical value of noninducibility of atrial fibrillation (AF) by isoproterenol (ISO) and by rapid atrial pacing (RAP) in patients with paroxysmal AF (PAF).

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).

Complex electrograms within the coronary sinus: time- and frequency-domain characteristics, effects of antral pulmonary vein isolation, and relationship to clinical outcome in patients with paroxysmal and persistent atrial fibrillation.

Background: The mechanistic and clinical significance of complex fractionated atrial electrograms (CFAE) in the coronary sinus (CS) has been unclear.

Randomized comparison of anatomic and electrogram mapping approaches to ablation of typical atrial flutter.

Isthmus Ablation. Introduction: The cavotricuspid isthmus can be ablated using an anatomic approach or an electrogram mapping approach in which sites at which there is a gap in the line of block are targeted. The aim of this study was to compare the anatomic and electrogram mapping approaches for creating a line of block in the cavotricuspid isthmus after an initial, unsuccessful anatomically directed ablation line.

Prevalence of fever in patients undergoing left atrial ablation of atrial fibrillation guided by barium esophagraphy.

Background: Real‐time esophageal imaging is critical in avoiding esophageal injury. However, the safety of esophageal imaging with barium has not been specifically explored.

Time- and Frequency-Domain Characteristics of Atrial Electrograms During Sinus Rhythm and Atrial Fibrillation

Ablation and Spectral Characteristics of Fibrillation. Background: Complex fractionated atrial electrograms (CFAE) have been considered to be helpful during catheter ablation of atrial fibrillation (AF). The purpose of this study was to analyze the characteristics of CFAEs recorded during sinus rhythm (SR) and AF, and to determine their relationship to perpetuation of AF and clinical outcome.

Delayed activation of the left atrial appendage following catheter ablation of persistent atrial fibrillation: A cause for concern?

Despite advances in catheter ablation of patients with persistent atrial fibrillation (AF), the ideal ablation strategy still is in evolution. It is known, however, that these patients fare poorly with pulmonary vein (PV) isolation alone.1 In an effort to improve outcomes, potential mechanisms of AF beyond the PVs have been targeted by left atrial linear ablation,2,3 ablation of complex fractionated atrial electrograms (CFAEs),4 ablation of ganglionated plexi, and a combination thereof. Recently, “stepwise ablation,” consisting of PV isolation, ablation of CFAEs, and linear ablation in an effort to terminate AF, has been reported to be highly effective in patients with persistent AF.5 However, extensive ablation may be associated with impairment of left atrial (LA) contractility. Although sinus rhythm may have been attained, altered LA activation and mechanical function may lead to AV dyssynchrony and an ongoing risk of thromboembolic complications. In this issue of PACE, Jiang et al. present their experience with extensive LA ablation in patients with persistent AF and resultant conduction delay into the left atrial appendage (LAA).6 Among 201 patients with persistent AF, LAA delay, defined as the activation of the LAA after the onset of the QRS complex on the surface electrocardiogram, was observed in 23 patients (11%) after the first ablation procedure. The ablation strategy included PV isolation followed by linear ablation along the roof, LA septum (from the mitral annulus to the rightsided PVs or the roof line), mitral, and cavotricuspid isthmi. Delay in LAA activation developed in nine of the first 26 patients (35%). Therefore, linear septal ablation was abandoned in favor of ablation of septal CFAEs in the remaining 175 patients. As a result, delay in LAA activation occurred in only five of these patients (3%). LAA activation delay also developed in nine of 45 patients (20%)

Recurrent Syncope in a Patient with an Implantable Loop Recorder: What is the Diagnosis?

A 76-year-old woman with a history of hypertension and mastectomy for breast carcinoma was referred for evaluation of recurrent syncope. She characterized a typical episode as a sudden loss of consciousness without a prodrome. There was no sensation of fatigue after the events. Her medical regimen consisted of amlodipine and a hydrochlorothiazide/triamterene combination. Results of physical examination were unremarkable. ECG showed sinus rhythm with a left bundle branch block and normal PR and QT intervals. Results of echocardiogram, exercise stress test, 24-hour Holter monitor, and a head-up tilt-table test were normal. She had no syncope, and no arrhythmias were detected while she wore a 30-day external event recorder. Electrophysiologic study including carotid sinus massage was notable only for spontaneous and pacing-induced atrial x8e brillation. In view of the nonspecix8e c electrophysiologic study, a loop recorder (Reveal Plus, Medtronic Inc., Minneapolis, MN, USA) was implanted. The loop recorder was implanted on the right side because the patient had undergone a radical mastectomy and was left with little subcutaneous tissue on the left side. The patient had an episode of syncope 6 weeks after the loop recorder was implanted. The retrieved electrogram from the patient-activated event is shown in Figure 1. What is the diagnosis of the implantable loop recording?