Outcomes of adjunct posterior wall isolation in atrial fibrillation patients with cardiac implantable electronic devices.

BACKGROUND: Although pulmonary vein isolation (PVI) remains the cornerstone of catheter ablation of atrial fibrillation (AF), several studies have illustrated clinical benefits associated with PVI with posterior wall isolation (PWI). METHODS: This retrospective study investigated the outcomes of PVI alone versus PVI+PWI performed using the cryoballoon in patients with cardiac implantable electronic devices (CIEDs) and paroxysmal AF (PAF) or persistent AF (PersAF). RESULTS: Acute PVI was achieved in all patients using cryoballoon ablation. Compared to PVI alone, PVI+PWI was associated with longer cryoablation, fluoroscopy, and total procedure times. Adjunct radiofrequency was required to complete PWI in 29/77 patients (37.7%). Adverse events were similar with PVI alone versus PVI+PWI. But at 24 ± 7 months of follow-up, not only cryoballoon PVI+PWI was associated with improved freedom from recurrent AF (74.3% vs. 46.0%, P = .007) and all atrial tachyarrhythmias (71.4% vs. 38.1%, P = .001) in patients with PersAF, cryoballoon PVI+PWI also yielded greater freedom from AF (88.1% vs. 63.7%, P = .003) and all atrial tachyarrhythmias (83.3% vs. 60.8%, P = .008) in those with PAF. Additionally, PVI+PWI was associated with higher reductions in atrial tachyarrhythmia burden (97.9% vs. 91.6%, P < .001), need for cardioversion (5.2% vs. 23.6%, P < .001) and repeat catheter ablation (10.4% vs. 26.1%, P = .005), and a longer time-to-arrhythmia recurrence (16 ± 6 months vs. 8 ± 5 months, P < .001) in both PersAF and PAF patients. CONCLUSION: In CIED patients with PersAF or PAF, cryoballoon PVI+PWI is associated with a greater freedom from recurrent AF and atrial tachyarrhythmias, as compared to PVI alone during long-term follow-up.

The importance of atrial fibrillation burden and the origin of device-tailored anticoagulation.

The current paradigm for anticoagulation in patients with atrial fibrillation is based upon clinical risk factors for stroke without reference to the frequency or duration (i.e., burden) of atrial fibrillation episodes. In the last decade, increasing evidence derived from device-based surveillance of atrial fibrillation has suggested that in some patients the burden of atrial fibrillation may be associated with thromboembolic risk. The development of rapidly acting oral anticoagulants and devices with remote monitoring capability has allowed the testing of a strategy of tailored or "pill-in-the-pocket" anticoagulation based upon atrial fibrillation burden.

Heart failure and tachycardia-induced cardiomyopathy.

Congestive heart failure is a major health care concern affecting almost six million Americans and an estimated 23 million people worldwide, and its prevalence is increasing with time. Long-standing tachycardia is a well-recognized cause of heart failure and left ventricular dysfunction and has led to the nomenclature, tachycardia-induced cardiomyopathy. Tachycardia-induced cardiomyopathy is generally a reversible cardiomyopathy with effective treatment of the causative arrhythmia, either with medications, surgery, or catheter ablation. Tachycardia-induced cardiomyopathy remains poorly understood and is likely under-diagnosed. A better understanding of tachycardia-induced cardiomyopathy and improved recognition of its presence in clinical practice is vital to the health of patients with this disorder. The goal of this review is to discuss the pathogenesis and clinical manifestations of tachycardia-induced cardiomyopathy, as well as approaches to its diagnosis and treatment.

Pulmonary Vein Isolation With and Without Posterior Wall Isolation in Paroxysmal Atrial Fibrillation: IMPPROVE-PAF Trial.

BACKGROUND: Prior studies have demonstrated clinical benefits associated with cryoballoon pulmonary vein isolation (PVI) and concomitant posterior wall isolation (PWI) in patients with persistent atrial fibrillation (AF). However, the role for this approach in patients with paroxysmal atrial fibrillation (PAF) remains unclear. OBJECTIVES: This study investigated the acute and long-term outcomes of PVI vs PVI+PWI using cryoballoon in patients with symptomatic PAF. METHODS: This retrospective study (NCT05296824) examined the outcomes of cryoballoon PVI (n = 1,342) vs cryoballoon PVI+PWI (n = 442) in patients with symptomatic PAF during long-term follow-up. Using the nearest-neighbor method, a 1:1 matched sample of patients receiving PVI alone and PVI+PWI was created. RESULTS: The matched cohort consisted of 320 patients (PVI: n = 160; PVI+PWI: n = 160). PVI+PWI was associated with longer cryoablation (23 ± 10 minutes vs 42 ± 11 minutes; P < 0.001) and procedure times (103 ± 24 minutes vs 127 ± 14 minutes; P < 0.001). In 39 (24.4%) of 160 patients, adjunct radiofrequency ablation was required for PVI+PWI. Adverse event rates were similar (PVI 3.8% vs PVI+PWI 1.9%; P = 0.31). Though there were no differences at 12 months, freedom from all atrial arrhythmias (67.5% vs 45.0%; P < 0.001) and AF (75.6% vs 55.0%; P < 0.001) were significantly greater with PVI+PWI vs PVI alone at 39 ± 9 months of follow-up. PVI+PWI was also associated with reduced long-term need for cardioversion (16.9% vs 27.5%; P = 0.02) and repeat catheter ablation (11.9% vs 26.3%; P = 0.001), and emerged as the only significant predictor of freedom from recurrent AF (HR: 2.79; 95% CI: 1.64-4.74; P < 0.001). CONCLUSIONS: Compared with cryoballoon PVI, cryoballoon PVI+PWI appears to be associated with greater freedom from recurrent atrial arrhythmias and AF in patients with PAF during long-term follow-up >3 years.

Death and near death from cardiac arrest during the Boston Marathon.

The Boston Marathon has been run for 115 years during which there were three sudden cardiac arrests. The most recent was a near death avoided by rapid cardiopulmonary resuscitation (CPR) and defibrillation. Awareness of the dangers of participating in a marathon, the risk factors associated with sudden death during competition, and the life-saving importance of rapid CPR and defibrillation are essential for participants and event organizers. Available records and reports of the three known cases of cardiac arrest during the Boston Marathon were examined. These cases were identified by representatives of the Boston Athletic Association, which has organized each marathon since its inception. Pertinent literature was reviewed and new information was obtained during interviews of witnesses and rescuers. The data were analyzed in search of shared risk factors for cardiac arrest, death, and the optimal requirements for survival. In 115 years, there were two cardiac deaths and one near death from cardiac arrest. A history of coronary artery disease, advanced age, and prolonged race time are risk factors for sudden cardiac arrest. Rapid application of CPR and defibrillation are essential for survival. Prevention or reduction of life-threatening cardiac incidents during marathon races might be achieved if participants of advanced age or with a history of coronary artery disease seek medical clearance prior to entering an event. Those with coronary risk factors should have a discussion with their physician. Availability of trained personnel and defibrillators are important considerations in marathon planning.

Painful left bundle branch block syndrome: Clinical and electrocardiographic features and further directions for evaluation and treatment.

BACKGROUND: Painful left bundle branch block (LBBB) is a rarely diagnosed chest pain syndrome caused by intermittent LBBB in the absence of myocardial ischemia. Its prevalence, mechanism, detailed electrocardiographic (ECG) features, and effective treatments are not well described. OBJECTIVES: The purpose of this study was to characterize clinical and ECG features of patients with painful LBBB syndrome with respect to the LBBB ECG morphology (in particular QRS axis and the precordial S/T wave ratio), clarify diagnostic criteria and possible mechanisms, and provide directions for further evaluation and treatment. METHODS: We analyzed clinical (n = 50) and ECG (n = 15) features of patients with painful LBBB syndrome (4 patients in our practice and 46 cases identified in the literature). RESULTS: All 15 ECGs of patients with painful LBBB syndrome had an inferior QRS axis and a very low (<1.8) precordial S/T wave ratio, which was consistent with the "new LBBB" pattern. We report a case of painful LBBB syndrome coexisting with coronary artery disease. Right ventricular apical pacing resolved intractable chest pain in 1 case of painful LBBB. CONCLUSION: Painful LBBB ECG morphology within seconds/minutes of its onset is consistent with the new LBBB pattern with a very low (<1.8) precordial S/T wave ratio and inferior QRS axis. Painful LBBB syndrome can coexist with coronary artery disease, complicating the assessment of chest pain in the setting of LBBB. An electrophysiology study might be considered to investigate whether changing ventricular activation pattern by pacing provides consistent pain control and to select the most effective pacing configuration.

Nonreentrant ventricular arrhythmias in patients with structural heart disease unrelated to abnormal myocardial substrate.

BACKGROUND: Ventricular arrhythmias in the absence of structural heart disease are commonly referred to as "idiopathic." Patients with structural heart disease have ventricular arrhythmias with the same mechanisms and sites of origin as idiopathic ventricular arrhythmias, but the prevalence of such arrhythmias is not well defined. OBJECTIVES: To identify the prevalence of nonreentrant ventricular arrhythmias unrelated to abnormal myocardial substrate in patients with structural heart disease and to compare these arrhythmias to ventricular arrhythmias in patients with structurally normal hearts. METHODS: Of 249 consecutive patients referred for ablation of ventricular arrhythmias, 97 (39%) patients had nonreentrant arrhythmias unrelated to underlying structural heart disease. Fifty-five (57%) patients had structurally normal hearts, and 42 (43%) had underlying structural heart disease. RESULTS: Compared with patients with structurally normal hearts, patients with structural heart disease were more likely to have nonreentrant ventricular arrhythmias unrelated to underlying abnormal myocardial substrate originating from the aortic cusps and left ventricular outflow tract whereas patients without structural heart disease more often had arrhythmias originating from the right ventricular outflow tract. There was a significant increase in the average left ventricular ejection fraction after ablation in patients with structural heart disease. CONCLUSION: Nonreentrant ventricular arrhythmias unrelated to abnormal myocardial substrate are common in patients with structural heart disease, and sites of origin differ from those seen in patients with structurally normal hearts. When managing structural heart disease in patients with ventricular arrhythmias, a focus on arrhythmia mechanism, origin, and relationship to underlying myocardial substrate may have important implications for future treatment options and patient outcomes.

What About Tachycardia-induced Cardiomyopathy?

Long-standing tachycardia is a well-recognised cause of heart failure and left ventricular dysfunction, and has led to the nomenclature, tachycardia-induced cardiomyopathy (TIC). TIC is generally a reversible cardiomyopathy if the causative tachycardia can be treated effectively, either with medications, surgery or catheter ablation. The diagnosis is usually made after demonstrating recovery of left ventricular function with normalisation of heart rate in the absence of other identifiable aetiologies. One hundred years after the first reported case of TIC, our understanding of the pathophysiology of TIC in humans remains limited despite extensive work in animal models of TIC. In this review we will discuss the proposed mechanisms of TIC, the causative tachyarrhythmias and their treatment, outcomes for patients diagnosed with TIC, and future directions for research and clinical care.

Body Mass Index, Quality of Life, and Catheter Ablation in Patients with Atrial Fibrillation.

Atrial fibrillation and obesity are interlinked epidemics and both impair quality of life. As the prevalence of both conditions in the US continues to rise, so will the number of obese patients with atrial fibrillation referred for catheter ablation. Catheter ablation has already been shown to significantly improve quality of life in patients with atrial fibrillation. Until recently, there has been little attention to the effects of catheter ablation on quality of life specifically in obese patients with atrial fibrillation. This paper will review what is known about the effects of atrial fibrillation and obesity on quality of life and how quality of life is affected by catheter ablation for atrial fibrillation in obese patients.

Trends in utilization and complications of catheter ablation for atrial fibrillation in Medicare beneficiaries.

BACKGROUND: Utilization of radiofrequency catheter ablation (RFA) for treatment of atrial fibrillation (AF) is increasing. Data regarding the safety of RFA for AF outside of selected centers of excellence and in older patients are limited. OBJECTIVE: The purpose of this study was to quantify utilization of RFA for treatment of AF and rates of adverse events over time in unselected U.S. Medicare patients. METHODS: Using Medicare Provider Analysis and Review (MedPAR) files for fiscal years 2001-2006, we developed a coding algorithm to identify AF patients treated with RFA. The number of hospitals performing the procedure, the number of procedures performed, and the frequency of eight RFA complications were determined. The impact of patient characteristics on complication rates was assessed using multivariable logistic regression. RESULTS: For fiscal years 2001 to 2006, the number of hospitals performing RFA for AF in Medicare patients increased from 100 to 162, and the annual total procedure volume increased from 315 to 1975 cases. The overall complication rate was 9.1%. Annual complication rates increased from 6.7% in 2001 to 10.1% in 2006 (P for trend = .01), mainly due to an increase in rates of vascular access complications. Increasing patient age was not associated with a higher complication rate. Hospital procedural volume was not associated with the overall risk of complications but was associated with the probability of in-hospital death. CONCLUSION: For fiscal years 2001-2006, use of RFA for treatment of AF increased markedly in the Medicare population. Overall complication rates rose during this time, with perforation/tamponade and vascular access complications accounting for the majority of events.

Sleep associated gas exchange abnormalities in children and adolescents with habitual snoring.

STUDY OBJECTIVES: The purpose of this study was to describe the prevalence of polysomnographically diagnosed OSAS and to describe the severity of sleep associated gas exchange abnormalities (SAGEA) in habitually snoring children. We hypothesized that there would be a high prevalence of OSAS in obese children with habitual snoring and that the most overweight children would have the most significant SAGEA. DESIGN: Retrospective chart review. MEASUREMENTS AND RESULTS: Nocturnal polysomnography (NPSG) data from 114 children and adolescents referred for habitual snoring were examined. 74 of the subjects were male (65%), average age of 9.78 +/- 4.19 years, average AHI 13.51 +/- 20.25, mean BMI z-score 1.79 +/- 1.18. BMI z-scores correlated positively with severity of OSAS (P < 0.05) such that children with progressive degrees of obesity had more frequent respiratory events during sleep. Additionally, severity of sleeping hypercapnea as measured by percent of total sleep time with EtCO(2) values above 50 mm Hg was more severe with progressive degrees of obesity. Likewise, all measures of oxyhemoglobin desaturation were more severe with progressive degrees of obesity. Positive correlations between the severity of SAGEA and degree of obesity remained even after controlling for the severity of OSAS. CONCLUSIONS: OSAS is highly prevalent in children referred to a pediatric sleep center with complaints of habitual snoring across a wide spectrum of weight categories. SAGEA increases with progressive obesity even when controlling for the severity of OSAS suggesting that obesity is an independent risk factor for SAGEA. Furthermore, because obese children frequently have SAGEA, capnography should be obtained during NPSG when possible.