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Objectives: Evaluate the efficacy, outcomes, and complications associatedwith direct current cardioversion (DCCV) in the treatment of arrhythmias in pediatric and adult congenital heart disease (CHD) populations and identify patient and procedural characteristics associated with adverse events. Background: Pediatric and adult patients with CHD are at risk of atrial arrhythmias. DCCV is effective but is associated with potential complications. Methods: In this single-center retrospective series, patients who underwent DCCV between January 2010 and May 2015 were identified and categorized as pediatric (<18 years) or adult (> 18 years). Records were reviewed for demographic, arrhythmic, and CHD-specific characteristics; acute efficacy; and 3-month arrhythmia recurrence. Complications were categorized as lifethreatening (LT) or non-life-threatening (NLT). Univariate followed by multiple variable and logistic regression (LR) analyses were used to identify characteristics associated with complications. Results: We identified 104 patients with 152 discrete DCCV events with median age 17.4 years (0.15-62.2). DCCV efficacy was 89% with 3-month recurrence of 46%. There were 52 complications among 24 patients, median age 17.7 years (0.15-49). Risks associated with NLT complications are as follows: moderate-severe systolic dysfunction (8/152 encounters, P = < 0.01) and more than one shock per DCCV encounter (P = < 0.01). Six of eight encounters with moderate-severe systolic dysfunction were <18 years (P = 0.1). Risks for LT complications included age >18 years and associated NLT complication. Adults had more frequent arrhythmia recurrence within 3 months than children (P = < 0.01). Conclusions: DCCV is effective for arrhythmias but is associated with frequent recurrence, particularly in adult patients. Complications associated with DCCV may be greater than previously reported. Additional support and precautions should be in place for those at greatest risk. [ABSTRACT FROM AUTHOR]

Background Atrial fibrillation (AF) recurrence is common after successful direct current cardioversion (DCCV), with a 40% rate of recurrence within the first month. Several studies have investigated the potential association between brain natriuretic peptide (BNP) or N-terminal (NT)-proBNP levels before DCCV and the risk of AF recurrence, but results have been inconsistent. We, therefore, conducted a systematic review and meta-analysis of all available data to determine whether sinus rhythm (SR) maintenance after successful DCCV may be determined by preprocedural BNP and NT-proBNP levels. Methods We systematically searched Scopus, the Cochrane library, EMBASE, and MEDLINE databases to identify publications evaluating BNP or NT-proBNP levels in relation to post-DCCV AF recurrence, indexed from inception to September 2013. Among the initial 1,067 citations, 18 studies fulfilled the specified criteria. The difference in BNP and NT-proBNP concentrations in the AF recurrence and the SR-maintaining group was estimated by the standardized mean difference and the estimates of the pooled outcomes were evaluated using random-effects models. Results Baseline BNP levels in the AF recurrence group were significantly higher compared to BNP levels in the SR-maintaining group (standardized mean difference [SMD] -1.51, confidence interval [CI] [-2.53, -0.48], P = 0.004). Similar results were observed for NT-proBNP levels, which were significantly higher in the AF recurrence group compared with the SR-maintaining group (SMD -0.63, CI [-1.13, -0.14], P = 0.01). Conclusions Our analysis suggests that low preprocedural BNP/NT-proBNP levels are associated with SR maintenance. The use of BNP or NT-proBNP for prediction of long-term response to DCCV appears to be useful and should be further evaluated. [ABSTRACT FROM AUTHOR]

Background: The optimal waveform tilt for defibrillation is not known. Most modern defibrillators used for the cardioversion of atrial fibrillation (AF) employ high-tilt, capacitor-based biphasic waveforms. Methods: We have developed a low-tilt biphasic waveform for defibrillation. This low-tilt waveform was compared with a conventional waveform of equivalent duration and voltage in patients with AF. Patients with persistent AF or AF induced during a routine electrophysiology study (EPS) were randomized to receive either the low-tilt waveform or a conventional waveform. Defibrillation electrodes were positioned in the right atrial appendage and distal coronary sinus. Phase 1 peak voltage was increased in a stepwise progression from 50 V to 300V. Shock success was defined as return of sinus rhythm for ≥30 seconds. Results: The low-tilt waveform produced successful termination of persistent AF at a mean voltage of 223 V (8.2 J) versus 270 V (6.7 J) with the conventional waveform (P = 0.002 for voltage, P = ns for energy). In patients with induced AF the mean voltage for the low-tilt waveform was 91V (1.6 J) and for the conventional waveform was 158 V (2.0 J) (P = 0.005 for voltage, P = ns for energy). The waveform was much more successful at very low voltages (less than or equal to 100 V) compared with the conventional waveform (Novel: 82% vs Conventional 22%, P = 0.008). Conclusion: The low-tilt biphasic waveform was more successful for the internal cardioversion of both persistent and induced AF in patients (in terms of leading edge voltage). [ABSTRACT FROM AUTHOR]

Over the past decade transesophageal echocardiography (TEE) has become an integral tool in the management of patients with AF. Thrombi can be readily detected and the function of the left atrium and left atrial appendage (LAA) can be easily assessed by this modality. With this knowledge, informed decisions regarding anticoagulation, cardioversion, and the likelihood of restoring and maintaining sinus rhythm can be made. An alternative TEE-guided strategy for achieving sinus rhythm in patients with AF is now available with efficacy and safety similar to the conventional approach. Refinements of this strategy may include the use of low molecular weight heparin to avoid hospitalization in patients planned for cardioversion. Further uses of TEE in patients with AF are in their early stages including evaluation of patients following pulmonary vein radiofrequency ablation and those undergoing percutaneous or surgical closure of the LAA. (PACE 2003; 26[Pt. II]:1597–1603). [ABSTRACT FROM AUTHOR]

The effectiveness and safety of internal transcatheter cardioversion on chronic lone atrial fibrillation were examined in ten patients resistant to external electrical (400 joules) and pharmacological cardioversion. Transcatheter cardioversion was performed by pulling back the atrioventricular junction catheter just inferior to the site of the His-bundle recording and delivering the shock between a proximal electrode (cathode) and backplate (anode). Transcatheter cardioversion restored sinus rhythm in all of the ten patients. The only complication observed was transient atrioventricular block after the shock and this was treated by temporary pacing. However, atrial fibrillation recurred in five patients at 30. 27, 52, 1, and 6 days, respectively. A second attempt at transcatheter cardioversion was performed in those patients and was successful in three patients. During a follow-up period ranging from 12 to 22 months, eight patients continued in sinus rhythm. Thus, transcatheter cardioversion is considered effective and safe in selected patients with chronic lone atrial fibrillation in whom external cardioversion was unsuccessful. [ABSTRACT FROM AUTHOR]

A patient with a dual chamber pacemaker received two transthoracic (anterior-anterior paddle position) shocks for VF. Subsequent analysis of stimulation thresholds revealed a marked rise in the ventricular threshold only. Later, she received three additional shocks (anterior-posterior paddle position) during electrophysiological study to terminate episodes of induced VT. Following these, the ventricular stimulation threshold was > 10 Vat 2.0 ms. The selective damage at the ventricular site in this patient led us to carry out in vitro studies that revealed a preferential shunting of high electrical energy into the ventricular lead, as compared to the atrial lead, following a DC shock. These observations may explain the selective pacing malfunction observed in our patient. [ABSTRACT FROM AUTHOR]