Exploratory use of intraprocedural transesophageal echocardiography to guide implantation of the leadless pacemaker.

Background: Fluoroscopy is the standard tool for transvenous implantation of traditional and leadless pacemakers (LPs). LPs are used to avoid complications of conventional pacemakers, but there still is a 6.5% risk of major complications. Mid-right ventricular (RV) septal device implantation is suggested to decrease the risk, but helpful cardiac landmarks cannot be visualized under fluoroscopy. Transesophageal echocardiography (TEE) is an alternative intraprocedural imaging method. Objective: The purpose of this study was to explore the spatial relationship of the LP to cardiac landmarks via TEE and their correlations with electrocardiographic (ECG) parameters, and to outline an intraprocedural method to confirm mid-RV nonapical lead positioning. Methods: Fifty-six patients undergoing implantation of LP with TEE guidance were enrolled in the study. Device position was evaluated by fluoroscopy, ECG, and TEE. Distances between the device and cardiac landmarks were measured by TEE and analyzed with ECG parameters with and without RV pacing. Results: Mid-RV septal positioning was achieved in all patients. TEE transgastric view (0°-40°/90°-130°) was the optimal view for visualizing device position. Mean tricuspid valve-LP distance was 4.9 ± 0.9 cm, mean pulmonary valve-LP distance was 4.2 ± 1 cm, and calculated RV apex-LP distance was 2.9 ± 1 cm. Mean LP paced QRS width was 160.8 ± 28 ms and increased from 117.2 ± 34 ms at baseline. LP RV pacing resulted in left bundle branch block pattern on ECG and 37.8% QRS widening by 43.5 ± 29 ms. Conclusion: TEE may guide LP implantation in the nonapical mid-RV position. Further studies are required to establish whether this technique reduces implant complications compared with conventional fluoroscopy.

Inappropriate Shock from Subcutaneous Implantable Cardioverter-Defibrillator Caused by Electrical Remodeling After Wolff-Parkinson-White Ablation.

Hypertrophic cardiomyopathy (HCM) and Wolff-Parkinson-White syndrome have been associated with sudden cardiac death. A subcutaneous implantable cardioverter-defibrillator (S-ICD) is an effective device used to reduce the risk of sudden cardiac death in these patients. The most common cause of inappropriate shocks with S-ICD is T-wave oversensing. We present the case of a 19-year-old man with repeated shocks from his S-ICD. This case highlights some of the sensing issues related to the S-ICD that can result in inappropriate shocks. A vector change may have occurred after T-wave remodeling, post accessory pathway ablation, and loss of R-waves due to HCM scar progression, leading to this consequence.

Bariatric surgery to aLleviate OCcurrence of Atrial Fibrillation Hospitalization-BLOC-AF.

BACKGROUND: Obesity is associated with a higher incidence of atrial fibrillation (AF). Weight reduction improves outcomes in patients known to have AF. OBJECTIVE: The purpose of this study was to compare the incidence of heart failure (HF) or first-time AF hospitalization in obese patients undergoing bariatric surgery (BAS) vs other abdominal surgeries. METHODS: A retrospective cohort study was conducted using linked hospital discharge records from 1994-2014. Obese patients without known AF or atrial flutter (AFL) who had undergone abdominal hernia or laparoscopic cholecystectomy surgery were identified for each case that underwent BAS (2:1). Clinical outcomes were HF, first-time hospitalization for AF, AFL, gastrointestinal bleeding (GIB), and ischemic or hemorrhagic stroke. Outcomes were analyzed using conditional proportional hazard modeling accounting for the competing risk of death, adjusting for demographics and comorbidities. RESULTS: There were 1581 BAS cases and 3162 controls (48% age <50 years; 60% white; 79% female; mean CHA2DS2VASc score 1.6 ± 1.2) with follow-up of 66 months. Compared to controls, BAS cases had a significantly lower risk of new-onset AF (hazard ratio [HR] 0.71; 95% confidence interval [CI] 0.54-0.93) or HF (HR 0.74; 95% CI 0.60-0.91) but a higher risk of GIB (HR 2.1; 95% CI 1.5-3.0), with no differences in AFL, ischemic stroke, or hemorrhagic stroke. Reduction in AF improved as follow-up increased beyond 60 months. CONCLUSION: In patients undergoing BAS, the risk of either HF or AF was reduced by ∼29% but with greater risk of GIB. The findings support the hypothesis that weight loss reduces the long-term risk of HF or incident AF hospitalization.

Posterior Wall Isolation for Atrial Fibrillation: Effects on Echocardiographic Parameters of cardiac function.

BACKGROUND: Posterior wall isolation (PWI) in addition to circumferential pulmonary vein isolation (CPVA) requires more ablation of left atrial tissue. We compared the effect of PWI versus non-PWI methods (CPVA + linear lesions) on echocardiographic parameters of left atrial and left ventricular function. METHODS: We selected patients who had pre and post ablation echocardiogram at our institution. Parameters assessed were: Left ventricular outflow tract velocity time integral (VTI), left ventricular ejection fraction (LVEF), atrial Doppler velocity across mitral valve (A), E/E', and deceleration time. RESULTS: Of the 72 patients studied, 32.5% had PWA in addition to CPVA. The mean duration between echocardiograms was 650 + 542 days. PWA group had an average postoperative VTI 0.21 + 0.05 vs 0.21 + 0.05 in the non-PWA (p=0.61) group. Average improvement compared to pre ablation parameters: VTI was 0.03 + 0.06 vs 0.008 + 0.05 (p=0.17), postoperative A was 0.49 + 0.19 vs 0.57 + 0.19 (p=0.16), postoperative LVEF was 57.5 + 9.9% vs 57.8 + 10.8 % (p=0.89), with average change in LVEF 1.5 ± 7.8 vs 0.86 ± 9.7 (p=0.78) in PWA and non-PWA groups respectively. There was no significant difference in change in deceleration time or E/E' when comparing the two groups. CONCLUSIONS: PWA did not adversely affect echocardiographic parameters of left atrial function or left ventricular systolic or diastolic function when compared to other types of ablation.

QT correction in atrial fibrillation - Measurement revisited.

BACKGROUND: QT interval measured in the electrocardiogram (ECG) varies with RR interval challenging the calculation of corrected QT (QTc) in Atrial fibrillation (AF). OBJECTIVES: To identify the ideal Lead, number of complexes and the formula to measure QTc that correlates best between AF and sinus rhythm (SR). PROCEDURE: We identified ECGs from patients with AF before and after conversion to SR. After excluding patients on drugs and clinical conditions that prolong QT interval, QTc was calculated from all the leads using the formulae: Bazett (BF), Fridericia (FF), Framingham(FrF), Hodges (HF), Saige (SF) and Rautaharju (RF) during AF and SR. After identifying the lead with best linear correlation, we calculated QTc following the longest RR, multiple QRS complexes and average automated RR interval during AF and compared to SR. FINDINGS: In 52 patients (male 69%, age 63 ±â€¯9 yrs), QTc measured from Lead II correlated best with SR in majority of the formulae. QTc was consistently shorter with linear formulae. While BF overestimated QTc, FF was optimal comparing AF vs SR (416 ±â€¯33 vs 411 ±â€¯38 ms, ns) calculated from single, multiple or average automated RR interval. Bland Altman analysis of the average automated QTc versus the delta of individual automated QTcs shows the least variation in the QTc calculated by FF. CONCLUSIONS: BF in commercial software is not ideal for measurement of QTc in AF, Fridericia Formula in lead II from the average RR from automated ECG measurement maybe utilized for the calculation of QTc.

Comparison of Cryoballoon and Hybrid surgical Posterior Wall Isolation for Persistent Atrial Fibrillation to conventional ablation.

BACKGROUND: Optimalablation strategy for persistent atrial fibrillation (AF) is unclear;PWI of the left atrium may improve outcome.Our aim was to compare outcomes of posterior wall isolation (PWI) ablation for persistent AF achieved by cryoballoon ablation (CRYO) or hybrid surgical ablation (HABL) to matched patients undergoing conventional radiofrequency ablation (CRA). METHODS: In our single center retrospective study,patients underwent HABL and CRYO withcircumferential pulmonary vein ablation (CPVA),roof and floor lines to complete PW box lesion. CRA consisted of CPVA, roof line and lateral mitral isthmus line (MVI). RESULTS: Of 61 patients (mean duration of AF 1.3 ± 0.4 yrs)who underwent ablation, after follow-up of 366 ± 62 days, AF recurrence was 10.5% and 48% (p=0.001) and the need for repeat ablation 5% vs 30% (p=0.007) in PWI and CRA groups respectively, without a significant difference in incidence of AT/FL 18 vs 26 % or cardioversion 5.2 vs 7.1 %. Total procedure time and fluoroscopic time were 242 ±70 min vs 279 ±53 min (p=0.08) and 20±9 min vs 12 ± 4 min (p=0.003) for PWI and CRA respectively. CRYO had less AF recurrence and complications than HABL. Mean length of stayfor CRYO patients was 41 hrs compared to 145 hrs in HABL group, who underwent two procedures. CONCLUSION: PWI in persistent AF patients decreases recurrence of AF and need for repeat procedure compared to CRA; PWI by CRYO is superior to HABL due to less LOS and complications.

California Study of Ablation for Atrial Fibrillation:Re-hospitalization for Cardiac Events (CAABL-CE).

BACKGROUND: Catheter ablation (ABL) for non-valvular (NV) atrial fibrillation (AF) improves rhythm control. Our aim was to compare re-hospitalization for heart failure (HF), acute coronary syndrome (ACS), or recurrent AF among patients with NVAF who underwent ABL versus controls. METHODS: From the Office of Statewide Planning and Development (OSHPD) database, we identified all patients who had at least one hospitalization for AF between 2005-2013. Patients who subsequently underwent ABL were compared to controls (up to fivematched controls by age, sex and duration of AF between diagnosis and time of ABL). Cases with valve disease, open maze, other arrhythmias, or implanted cardiac devices were excluded. Pre-specified clinical outcomes including readmission for HF, ACS, severe or simple AF (severe = with HF or ACS; simple= without HF or ACS)were assessed using a weighted proportional hazard model adjusting for number of hospital admissions with AF before the ABL, calendar year of ABL, and presence of chronic comorbidities. RESULTS: The study population constituted 8338 cases and controls, with mean 3.5+ 1 patient-year follow up. In the ABL cohort, there was lower risk of re-hospitalizations for HF, HR=0.55(95%CI: 0.43-0.69,); ACS,HR=0.5(95%CI: 0.35-0.72,); severe AF [HR=0.86 (CI:0.74-0.99), and higher for simple AF, HR=1.25 (CI:1.18-1.33). CONCLUSIONS: In patients with NVAF,although ABL is associated with increased risk of re-hospitalization for simple AF, ABL was associated with a significant reduction in the risk of re-hospitalization for HF, ACS and severe AF. These findingsrequireconfirmation in a prospective clinical trial.

CAABL-AF (California Study of Ablation for Atrial Fibrillation): Mortality and Stroke, 2005 to 2013.

BACKGROUND: Ablation for atrial fibrillation (AF) is superior to medical therapy for rhythm control. We compared stroke and mortality among patients undergoing ablation for AF to matched controls in a large multiethnic population. METHODS: Using discharge and surgical records from California nonfederal hospitals, we identified patients who had ablation and principal diagnosis of AF with at least 1 prior hospitalization for AF. We excluded cases with valve disease, open maze, other arrhythmias, or implantable devices. Matched controls were selected based on years of AF diagnosis, age, sex, and being alive the same number of days from the initial AF encounter to the ablation date. Clinical outcomes, including mortality, ischemic stroke, or hemorrhagic stroke, were assessed using a weighted proportional hazard model, adjusting for demographics, prior admissions with AF before the ablation, calendar year, and presence of chronic comorbidities. RESULTS: There were 4169 ablation cases and 4169 weighted-matched controls; 39% percent of the ablation group was >65 years, 72% men, 84% white; mean follow-up was up to 3.6±0.9 years. In adjusted models, ablation was associated with significantly lower mortality (per patient-years) 0.9% versus 1.9%, hazard ratio=0.59 (P<0.0001; confidence interval: 0.45-0.77); ischemic stroke (>30 days post-ablation ≤5 years), 0.37% versus 0.59%, hazard ratio=0.68 (P=0.04; confidence interval: 0.47-0.97); hemorrhagic stroke 0.11% versus 0.35%, hazard ratio=0.36 (P=0.001; confidence interval: 0.20-0.64) compared with controls. CONCLUSIONS: In this large population-based study of hospitalized patients with nonvalvular AF, ablation was associated with lower mortality, ischemic stroke, and hemorrhagic stroke compared with controls.

California study of Ablation (CAABL):early utilization after index hospitalization for non-valvular atrial fibrillation.

BACKGROUND: Catheter ablation (ABL) for non-valvular AF (NVAF) is recommended for symptomatic patients refractory to medical therapy and its success is related to the duration of the arrhythmia prior to intervention.Our aim was to assess the early utilization and the factors that prompted ABL in patients hospitalized for new onset NVAF. METHODS: Using de-identified administrative discharge records for hospitalizations and emergency department (ED) visits, we determined the patients who had a first-time (since 1991) health record diagnosis of AF between2005 - 2011. We linked ambulatory surgery encounters for ABL based on ICD 9 code occurring within two years of initial hospitalization. After excluding other cardiac arrhythmias, atrio-ventricular nodal ablation or pacemaker/defibrillator placement and cardiac valve disease, bivariate comparisons were made with those who did not undergo ABL. RESULTS: During the study period,3,440 of 424,592 patients (0.81%) hospitalized for new onset NVAF underwent ABL. Parameters significantly (p<0.001) associated with ABL compared tonon-ABL patientsincluded: principal diagnosis of AF (55% vs 25%), age 35-64 yrs (46.1% vs. 22.4%), male (58.9% vs. 48.2%), private insurance (46.6% vs. 21.1%), Caucasian (81.0% vs.71.6%), lower frequency of ED visit < 6 months before index AF hospitalization (10.7% vs. 15.9%), lower severityofillness at time of AF diagnosis (16.5% vs. 35.6%) anda lower prevalence ofmajor comorbidities (p< 0.001). CONCLUSIONS: Ablation has low utilization for treatment of new onset NVAF within two years of diagnosis. Earlier utilization of ABL may reduce health care burden related to NVAF and requires further evaluation.

Resolution of AV block after ablation for atrial fibrillation.

We report a case with complete atrioventricular block (AVB) present both during sinus rhythm and with atrial fibrillation (AF). He had declined pacemaker placement and opted for ablation for the symptomatic AF. He underwent staged hybrid approach with video-assisted thoracoscopic surgical maze (VATS) followed by endocardial ablation. VATS included ganglionic plexi cauterization. One month after the endocardial procedure, he had complete resolution of AF and AVB and remains so at 18 months follow up. We discuss possible abolition of vagal input for this improvement in AV conduction.

Risk predictors of stroke and mortality after ablation for atrial fibrillation: the California experience 2005-2009.

BACKGROUND: Ablation (ABL) is a second-line therapy for the management of atrial fibrillation (AF). Single-center studies have demonstrated the safety and efficacy of ABL; however, the low event rates render it difficult to assess predictors of major adverse events. OBJECTIVE: The purpose of this study was to determine the population-based incidence of data and risk factors for both stroke <30 days and death after AF ABL. METHODS: Patients (n = 6207) identified as having undergone AF ABL between 2005 and 2009 by the California Ambulatory Surgery Database in 97 nonfederal hospitals in California were linked to the California Patient Discharge Database and to a master death registry. Data from these patients were analyzed for primary outcomes of 30-day death and ischemic stroke. Independent risk factors for these end-points were determined. RESULTS: Mean patient age was 61.9 years, and the majority of the patients were men. Thirty-day mortality and stroke after ABL were 0.39% and 0.61%, respectively. Independent predictors of death were age ≥80 years (odds ratio [OR] 8.2, 95% confidence interval [CI] 1.5-43) and heart failure (OR 9.2, 95% CI 3.0-28). Prior stroke/transient ischemic attack/stroke was the only independent predictor for stroke (OR 6.3, 95% CI 3-13). CONCLUSION: In our large population-based study, we found higher procedure-related mortality but comparable stroke rate after AF ABL than previously reported. Age ≥80 years and heart failure was each independently associated with >8-fold increase in odds of death. The only significant predictor of stroke was prior stroke/transient ischemic attack. These findings may aid in patient selection for AF ABL.