BACKGROUND:Active esophageal cooling reduces the incidence of endoscopically identified severe esophageal lesions during radiofrequency (RF) catheter ablation of the left atrium for the treatment of atrial fibrillation. A formal analysis of the atrioesophageal fistula (AEF) rate with active esophageal cooling has not previously been performed. OBJECTIVES:The authors aimed to compare AEF rates before and after the adoption of active esophageal cooling. METHODS:This institutional review board (IRB)-approved study was a prospective analysis of retrospective data, designed before collecting and analyzing the real-world data. The number of AEFs occurring in equivalent time frames before and after adoption of cooling using a dedicated esophageal cooling device (ensoETM, Attune Medical) were quantified across 25 prespecified hospital systems. AEF rates were then compared using generalized estimating equations robust to cluster correlation. RESULTS:A total of 14,224 patients received active esophageal cooling during RF ablation across the 25 hospital systems, which included a total of 30 separate hospitals. In the time frames before adoption of active cooling, a total of 10,962 patients received primarily luminal esophageal temperature (LET) monitoring during their RF ablations. In the preadoption cohort, a total of 16 AEFs occurred, for an AEF rate of 0.146%, in line with other published estimates for procedures using LET monitoring. In the postadoption cohort, no AEFs were found in the prespecified sites, yielding an AEF rate of 0% (P < 0.0001). CONCLUSIONS:Adoption of active esophageal cooling during RF ablation of the left atrium for the treatment of atrial fibrillation was associated with a significant reduction in AEF rate.

ABSTRACTBackgroundActive esophageal cooling reduces the incidence of endoscopically identified severe esophageal lesions during radiofrequency (RF) catheter ablation of the left atrium for the treatment of atrial fibrillation. No atrioesophageal fistula (AEF) has been reported to date with active esophageal cooling, and only one pericardio-esophageal fistula has been reported; however, a formal analysis of the AEF rate with active esophageal cooling has not previously been performed.MethodsAtrial fibrillation ablation procedure volumes before and after adoption of active cooling using a dedicated esophageal cooling device (ensoETM, Attune Medical) were determined across 25 hospital systems with the highest total use of esophageal cooling during RF ablation. The number of AEFs occurring in equivalent time frames before and after adoption of cooling were then determined, and AEF rates were compared using generalized estimating equations robust to cluster correlation.ResultsThroughout the 25 hospital systems, which included a total of 30 separate hospitals, 14,224 patients received active esophageal cooling during RF ablation, with the earliest adoption beginning in March 2019 and the most recent beginning in March 2022. In the time frames prior to adoption of active cooling, a total of 10,962 patients received primarily luminal esophageal temperature (LET) monitoring during their RF ablations. In this pre-adoption cohort a total of 16 AEFs occurred, for an AEF rate of 0.146%, in line with other published estimates of <0.1% to 0.25%. No AEFs were found in the cohort treated after adoption of active esophageal cooling, yielding an AEF rate of 0% (P<0.0001).ConclusionAdoption of active esophageal cooling during RF ablation of the left atrium for the treatment of atrial fibrillation was associated with a significant reduction in AEF rate.

Atrioesophageal fistula (AEF) is a rare and serious complication of atrial fibrillation (AF) ablation, defined as a connection between the atrium and the lumen of the esophagus.1 AEF has an incidence of 0.1% to 0.25%2 and a mortality over 50%.3 AEF can occur with any of the available AF ablation modalities, including radiofrequency ablation (RFA), cryoballoon ablation, high-intensity focused ultrasound ablation, and surgical ablation.4 The clinical presentation of an AEF is usually seen 2–6 weeks post ablation.

BACKGROUND The energy delivered by a defibrillator is expressed in joules (J). However, current is what actually defibrillates the heart and is related to the voltage-to-impedance ratio. With the same energy, the lower the transthoracic impedance, the higher the current delivered. In obese patients, pushing the chest wall toward the heart during electric shock can result in an improved outcome. CASE REPORT We report the cases of 3 obese patients with previously failed cardioversion/defibrillation who had an eventual shock success. (1) A 17-year-old girl failed multiple defibrillation efforts for her recurrent ventricular fibrillation. After ECMO, with the physician pushing down the chest wall, a 200-J defibrillation converted her VF. (2) A 63-year-old man with recurrent atrial fibrillation (AF) had an unsuccessful 150-J shock followed by a successful 200-J cardioversion. His AF recurred. After amiodarone bolus, a 200-J shock converted it to sinus. Another recurrent AF failed 150-J cardioversion. With chest pushing down, a 150-J cardioversion was successful. (3) A 65-year-old man underwent elective cardioversion for AF. A 200-J shock was unsuccessful. A 200-J shock with pressure on the chest successfully converted it. CONCLUSIONS We performed successful electrical cardioversion/defibrillation with this "pushing down the chest while shocking" method. Many clinicians are still unaware of this method, especially in obese patients. With the increasing prevalence of obesity, it is urgent to perform a randomized study to confirm the efficacy and safety of this method, and integrate it into advanced cardiac life support protocols.

BACKGROUND Lown-Ganong-Levine syndrome, includes a short PR interval, normal QRS complex, and paroxysmal tachycardia. The pathophysiology of this syndrome includes an accessory pathway connecting the atria and the atrioventricular (AV) node (James fiber), or between the atria and the His bundle (Brechenmacher fiber). Similar features are seen in enhanced atrioventricular nodal conduction (EAVNC), with the underlying pathophysiology due to a fast pathway to the AV node, and with the diagnosis requiring specific electrophysiologic criteria. CASE REPORT A 17-year-old man presented with a history of recurrent narrow-complex and wide-complex tachycardia on electrocardiogram (ECG). An electrophysiologic study showed an unusually short atrial to His (AH) conduction interval and a normal His to ventricle (HV) interval, without a delta wave. Two stable AH intervals coexisted in the same atrial pacing cycle length. In the recovery curve study, this pathway had a flat conduction curve without an AH increase until the last 60 ms, before reaching the effective refractory period. These ECG changes did not respond to an adenosine challenge. When this pathway became intermittent, there was a paradoxical response to adenosine challenge with conduction via a short AH interval, but without conduction block. Catheter ablation of the AV nodal region resulted in a normalized AH interval, decremental conduction properties, and resulted in a positive response to an adenosine challenge. CONCLUSIONS In this case of Lown-Ganong-Levine syndrome, electrophysiologic studies supported the role of the accessory pathway of James fibers.

Key Clinical MessageIdiopathic ventricular tachycardia arising from the LV summit epicardial area can be successfully mapped and possibly ablated from the left atrial appendage.

Catheter ablation of drug-refractory ventricular tachycardia (VT) that occurs in infancy can be challenging owing to the small size of the heart and vessels compared to the ablation catheters. We present a toddler with incessant left ventricular (LV) tachycardia that was successfully treated by radiofrequency catheter ablation with an 8 French irrigated-tip catheter via a transapical approach. This technique can further expand the armamentarium for treating such patients.

Background: Transient variations in physiological parameters may forewarn of life-threatening cardiac events, but are difficult to identify clinically. Implantable cardioverter defibrillators (ICD) designed to measure transthoracic impedance provide a surrogate marker for pulmonary congestion.Objective: The aim of this study is to determine if the frequency of changes in transthoracic impedance (TTI) is associated with congestive heart failure (CHF) exacerbation and predicts mortality.Methods: We followed 109 consecutive patients (pts) with ICDs (n = 58) or CRT-ICDs (n = 51) for a mean of 21.3 (+ 10.2) months. Using 80 ohm-days as a reference, we correlated the frequency of TTI changes above this index to CHF hospitalizations or death.Results: There was at least one TTI threshold crossing in 79 (72%) pts over 23.3 months follow-up, with a mean of 1.8 +/- 3.4 per year. There were 18 pts with CHF hospitalizations who had a mean of 4.3 TTI threshold crossings/ year (S. D. = +/- 7.3; median = 2.8), compared to 1.3 (S. D. = +/- 1.5; median = 0.8) among pts without CHF hospitalizations (p = 0.0006). Among 20 patients who died during follow-up, there were 4.2 (S. D. = +/- 7.0; median = 2.9) TTI threshold crossings/year, compared with 1.3 (S. D. = +/- 1.3; median = 0.9) threshold crossings/ year among survivors (p = 0.0004). Using Cox Proportional Hazard modeling, after adjusting for age, baseline EF, and number of shocks, TTI threshold crossing was an independent predictor of death (HR 1.72, 95% CI 1.26-2.36, p = 0.001).Conclusions: Increased frequency of TTI threshold crossings may be a useful predictor of transient risk for identifying a subgroup of ICD recipients at greater individual risk for death or CHF hospitalizations. (C) 2014 Elsevier Ireland Ltd. All rights reserved.

BACKGROUND:The wearable defibrillator (WD) can prevent sudden death in patients who are not candidates for an implantable cardioverter-defibrillator (ICD). OBJECTIVES:We studied outcomes of uninsured patients prescribed a WD. METHODS:A consecutive series of patients were prescribed a WD because of a new onset cardiomyopathy or coronary artery revascularization with a predischarge ejection fraction (EF) ≤35%. Patients were followed up for WD compliance, events, EF changes, and subsequent ICD implants. RESULTS:Among 134 patients with cardiomyopathy diagnosed at a mean age of 52.7 ± 11.6 years and with a mean EF of 22.5% ± 7.3%, 125 patients (93%) were newly diagnosed with cardiomyopathy. There were 77 patients (57%) with nonischemic cardiomyopathy and 57 (43%) with ischemic cardiomyopathy. Patients wore the WD for a mean of 14.1 ± 8.1 hours per day for 72 ± 55 days. There were no shocks or detected arrhythmias. Forty-eight patients (35%) were lost to follow-up. No ICDs were implanted in 33 (38%) of the other 86 patients, whose EF improved to above 35%. Of the 53 patients with persistent EF ≤35%, 44 patients (83%) received an ICD. However, 12 (27%) of these 44 patients had ICD implant before 90 days after the index event. CONCLUSION:There was a high lost to follow-up rate in an uninsured population. There were no sustained ventricular tachyarrhythmia events. Wearable defibrillator utilization prevented ICD implant in the subgroup of patients with EF improvement, although there were still premature implants based on Centers for Medicare and Medicaid Guideline waiting periods.

Prior studies on radiation exposure in the electrophysiology lab have focused on ablation procedures and patient safety. There is very little data on operator safety. Biventricular (BiV) pacing has developed into an important therapy for patients with CHF, but the procedure itself adds significant radiation exposure time to operators mainly due to the time it takes to place the coronary sinus lead. The magnitude of this radiation load has never been investigated. The purpose of this study is to determine the amount of radiation exposure to operators incurred during BiV implants in an academic center.

A 62 year old woman with a history of a septal atrial myxoma resection and recent atrial flutter (AFL) was brought to the EP lab for radiofrequency ablation (RFA). During sinus rhythm, the His atrial electrogram followed the proximal coronary sinus (CS) atrial electrogram with a normal HV interval. Typical, counterclockwise isthmus-dependent AFL was induced. During RFA at the cavotricuspid isthmus (CTI), AFL terminated but CTI conduction was still present. Additional RFA during CS pacing led to CTI block with abrupt loss of lateral right atrial (RA) activation. When CS pacing was terminated, sinus rhythm and/or high RA pacing captured the lateral RA, but failed to conduct to the CS or the ventricle, resulting in "pseudo" AV block. We use the term "pseudo" block because CS pacing always resulted in 1:1 AV conduction. Since sinus activity was not reaching the AV node, the patient required a permanent pacemaker.

Global left ventricular (LV) systolic dysfunction is the strongest predictor of morbidity and mortality in Chagas disease. Echocardiography is considered the gold standard for the detection of LV dysfunction, but not always available in endemic areas where chagasic cardiomyopathy is most common. Brain natriuretic peptide (BNP) is a neurohormone that has been recently described as a simple and inexpensive diagnostic and prognostic marker for patients with congestive heart failure. Chagasic patients (n = 63) and non-infected healthy individuals (n = 18) were recruited prospectively and underwent complete clinical examination, echocardiography and 24-h Holter monitoring. BNP was measured from thawed plasma samples using the Triage BNP test. We observed high levels of BNP in association with depression of LV ejection fraction, with increase of LV end-diastolic diameter and with LV premature complexes. An elevated concentration of BNP, defined as a concentration of 60 pg/ml or more, had a sensitivity of 91.7%, specificity of 82.8%, positive predictive value of 52.4%, and negative predictive value of 98% for detecting LV dysfunction (LV ejection fraction < 40%).BNP measurement using a simple, relatively inexpensive and rapid test has a promising role in identifying LV dysfunction associated with chagasic cardiomyopathy. Equally important, patients with Trypanosoma cruzi infection who have low levels of BNP level in plasma have a very low likelihood of severe cardiac involvement, and echocardiography is probably not necessary.

Primary systemic amyloidosis (AL) is a rare, sporadic disease caused by deposition of immunoglobulin light chains in various tissues; symptoms vary based on which organs are infiltrated by the amyloid fibrils. Cardiac involvement occurs in up to 50% of patients with primary amyloidosis and is associated with a very poor prognosis. We report a case of a 57-year-old black man who presented with symptoms consistent with congestive heart failure. He was later found to have primary systemic amyloidosis, confirmed by abdominal fat pad biopsy.