Successful cryothermal ablation for Atrioventricular nodal reentry tachycardia after radiofrequency ablation failure.

BACKGROUND: Catheter ablation is the preferred management approach for atrioventricular nodal reentrant tachycardia (AVNRT). Cryothermal ablation (Cryo) and radiofrequency ablation (RFA) are the two clinically available ablation modalities. Atrioventricular (AV) block is a concerning potential complication and is commonly preceded by transient AV block or rapid junctional beats when using RFA. For challenging AVNRT cases, where RFA produced signs of impending AV block, we evaluate the application of Cryo to the same anatomical location where RFA was abandoned. METHODS: Cryo was applied in 10 out of 313 (3.2%) total AVNRT cases from January of 2007 to June of 2010. In these cases, right-sided RFA failed in eliminating AVNRT and was aborted due to transient AV block or rapid junctional rhythm. Cryo lesions were then applied to the same anatomical location where RFA was discontinued. Patients were followed and evaluated for AVNRT recurrence. RESULTS: Nine out of ten patients had complete elimination of AVNRT after Cryo, one of whom required a second procedure. This strategy failed in one patient, where left-sided RFA was required to eliminate AVNRT. There was one complication, tamponade, in the failed case, which was successfully managed with no long-term sequelae. There was no AV block. CONCLUSION: In this cohort of challenging AVNRT cases where right-sided RFA was aborted due to signs of impending AV block, applying Cryo to the same anatomical location provided procedural success, in all but one case. A prospective study is needed to accurately evaluate the safety and efficacy of this strategy.

Complications arising from catheter ablation of atrial fibrillation: temporal trends and predictors.

BACKGROUND: The reported complication rate of catheter ablation of atrial fibrillation (AF) varies. OBJECTIVE: Our goal was to assess temporal trends and the effect of both institutional and individual operators' experience on the incidence of complications. METHODS: All patients undergoing AF ablation at Johns Hopkins Hospital between February 2001 and December 2010 were prospectively enrolled in a database. Major complications were defined as those that were life-threatening, resulted in permanent harm, required intervention, or significantly prolonged hospitalization. RESULTS: Fifty-six major complications occurred in 1190 procedures (4.7%). The majority of complications were vascular (18; 1.5%), followed by pericardial tamponade (13; 1.1%) and cerebrovascular accident (12; 1.1%). No cases of death or atrioesophageal fistula occurred. The overall complication rate decreased from 11.1% in 2002 to 1.6% in 2010 (P <.05). On univariate analysis, demographic and clinical factors associated with the increased risk of complications were CHADS(2) score of ≥2 (hazard ratio [HR] = 2.5; 95% confidence interval [CI] = 1.4-4.4; P = .002), female gender (HR = 2.0; 95% CI = 1.2-3.5; P = .014), and age (HR = 1.03; 95% CI = 1.0-1.1; P = .042). Gender and CHADS(2) score of ≥2 remained independent predictors of complication on multivariable analysis. CONCLUSION: The complication rate of catheter ablation of AF decreased with increased institutional experience. Female gender and CHADS(2) score of ≥2 are significant independent risk factors for complications and should be considered when referring patients for AF ablation.

Premature failure of a Riata defibrillator lead without impedance change or inappropriate sensing: a case report and review of the literature.

A 63-year-old woman with a St. Jude Medical Riata 1570 right ventricular lead complained of intermittent hiccups 2 months after implant. Interrogation revealed elevated pacing threshold and diaphragmatic stimulation. Pacing and shock lead impedances remained stable. No inappropriate sensing was noted. Fluoroscopic examination of the lead revealed a thin radio-opaque wire seen between the 2 defibrillator coils away from the main body of the lead. After extraction, a tear in the insulation of the lead was noted allowing the inner wire to protrude. This case illustrates a novel mechanism of insulation failure without inappropriate sensing or impedance change.

Demographic profile of patients undergoing catheter ablation of atrial fibrillation.

BACKGROUND: Catheter ablation is a widely accepted treatment for drug refractory atrial fibrillation (AF). The purpose of our study was to examine secular trends in the demographic profile of patients undergoing AF ablation. METHODS AND RESULTS: Data for 792 patients who underwent catheter ablation for AF at Johns Hopkins Hospital between years 2001 and 2009 were systematically reviewed. There has been a steady increase in total number of procedures and repeat procedures. The majority of patients undergoing AF ablation at our institution are men (76.6%). Females accounted for 36.0% of patients in 2001 versus 19.6% in 2009. A total of 93.3% of patients undergoing AF ablation were Caucasian. The mean age of patients has increased over time (52 years in 2001 to 60 years in 2009, P = 0.015) and the number of antiarrhythmic drugs (AADs) used prior to first ablation has decreased (2.3 to 1.2, P = 0.009). In addition, the mean duration of AF prior to first referral has decreased (7.8 years in 2001 vs 4.2 years in 2009). CONCLUSION: There is a significant gender and racial disparity in patients undergoing AF ablation favoring Caucasian men that warrants further investigation. We also observed a significant increase in age of patients, decrease in number of AADs, and increase in number of repeat procedures. These results are important when interpreting outcomes of AF ablation and designing future trials.