Atrioesophageal Fistula Rates Before and After Adoption of Active Esophageal Cooling During Atrial Fibrillation Ablation.

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.

The Maine vein of Marshall ethanol experience: learning curve and safety.

BACKGROUND: The marginal benefit of ethanol infusion into the vein of Marshall (VOM) as an adjunct to atrial fibrillation ablation has shown promise in a single randomized study and case series from very experienced centers. However, adoption has not been widespread and the impact on real-world outcomes outside of leading centers is not established. The objective in this study is to understand the learning curve, and explore procedural outcomes and safety with VOM ethanol infusion from a large single medical center. METHODS: One hundred twenty nine atrial ablation cases wherein VOM ethanol infusion was attempted were identified from the time of the program's inception in 2019 at Maine Medical Center (Portland, ME). Our technical approach, procedural success, and complications were adjudicated from the medical record. RESULTS: The overall VOM ethanol infusion success was 90%. Infusion success rates improved and fluoroscopy utilization decreased with experience. Arrhythmia recurrence was 14% after a mean follow-up of 9.5 months. Complications occurred in 5.4% of patients, including a 3.1% risk of delayed tamponade. CONCLUSION: In our single center experience, VOM ethanol infusion was feasible with a high technical success rate. These positive results are balanced against a concerning rate of delayed tamponade.

Acute echocardiographic and hemodynamic response to his-bundle pacing in patients with first-degree atrioventricular block.

BACKGROUND: Atrial pacing and right ventricular (RV) pacing are both associated with adverse outcomes among patients with first-degree atrioventricular block (1°AVB). His-bundle pacing (HBP) provides physiological activation of the ventricle and may be able to improve both atrioventricular (AV) and inter-ventricular synchrony in 1°AVB patients. This study evaluates the acute echocardiographic and hemodynamic effects of atrial, atrial-His-bundle sequential (AH), and atrial-ventricular (AV) sequential pacing in 1°AVB patients. METHODS: Patients with 1°AVB undergoing atrial fibrillation ablation were included. Following left atrial (LA) catheterization, patients underwent atrial, AH- and AV-sequential pacing. LA/left ventricular (LV) pressure and echocardiographic measurements during the pacing protocols were compared. RESULTS: Thirteen patients with 1°AVB (mean PR 221 ± 26 ms) were included. The PR interval was prolonged with atrial pacing compared to baseline (275 ± 73 ms, p = .005). LV ejection fraction (LVEF) was highest during atrial pacing (62 ± 11%), intermediate with AH-sequential pacing (59 ± 7%), and lowest with AV-sequential pacing (57 ± 12%) though these differences were not statistically significant. No significant differences were found in LA or LV mean pressures or LV dP/dT. LA and LV volumes, isovolumetric times, electromechanical delays, and global longitudinal strains were similar across pacing protocols. CONCLUSION: Despite pronounced PR prolongation, the acute effects of atrial pacing were not significantly different than AH- or AV-sequential pacing. Normalizing atrioventricular and/or inter-ventricular dyssynchrony did not result in acute improvements in cardiac output or loading conditions.

Predicting the Development of Reduced Left Ventricular Ejection Fraction in Patients With Left Bundle Branch Block.

Left bundle branch block (LBBB) increases the likelihood of developing reduced left ventricular (LV) ejection fraction (EF) but predicting which patients with LBBB and normal LVEF will develop decreased LVEF remains challenging. Fifty patients with LBBB and normal LVEF were retrospectively identified. Clinical, electrocardiographic, and echocardiographic variables were compared between patients who developed a decreased LVEF and those who did not. A total of 16 of 50 patients developed reduced LVEF after 4.3 (SD = 2.8) years of follow-up. Baseline patient and electrocardiographic variables were similar between patients who did and did not develop decreased LVEF. Baseline LVEF was lower in patients who developed decreased LVEF than in those who did not (51.9% [SD = 2.2%] vs 54.9% [SD = 4.4%], p <0.01). Diastolic filling time (DFT) accounted for a significantly smaller percentage of the cardiac cycle in patients who developed decreased LVEF than in those who did not (35.9%, [SD = 6.9%] vs 44.4% [SD = 4.5%] p <0.01). In univariable logistic regression, DFT had a C-statistic of 0.86 (p <0.0001) for prediction of development of decreased LVEF. In conclusion, patients in whom DFT accounted for <38% of the cardiac cycle had a relative risk of developing decreased LVEF of 7.0 (95% confidence interval 3.0 to 16.0) compared to patients with DFT accounting for ≥38% of the cardiac cycle.

Left bundle branch block-induced left ventricular remodeling and its potential for reverse remodeling.

With the emergence of cardiac resynchronization therapy (CRT) as a powerful tool to reverse left ventricular dysfunction in patients with left bundle branch block (LBBB), there is increasing awareness that LBBB-induced dyssynchrony may be a primary cause of heart failure with reduced ejection fraction (HFrEF). Current guidelines for implanting CRT require at least 3 months of guideline-directed medical therapy (GDMT) before device implantation in the hopes that medications will reverse cardiomyopathy and obviate the need for device therapy. However, no randomized controlled trial demonstrating efficacy of medications ever stratified outcomes by patients with conduction abnormalities. Consequently, CRT, not GDMT, may be a more effective first-line therapy for patients with LBBB and HFrEF. This review evaluates the evidence for LBBB-induced cardiomyopathy, examines the rationale for GDMT in this population, and presents the evidence for direct implantation of CRT. It is likely that many patients would benefit from earlier intervention with CRT, though about 25% of patients with LBBB and HFrEF may respond to GDMT.

Impaired Recovery of Left Ventricular Function in Patients With Cardiomyopathy and Left Bundle Branch Block.

BACKGROUND: Patients with left bundle branch block (LBBB) often respond to cardiac resynchronization therapy (CRT) with left ventricular ejection fraction (LVEF) improvement. Guideline-directed medical therapy (GDMT), not CRT, is first-line therapy for patients with reduced LVEF with LBBB. However, there are little data on how patients with reduced LVEF and LBBB respond to GDMT. OBJECTIVES: This study examined patients with cardiomyopathy and sought to assess rates of LVEF improvement for patients with LBBB compared to other QRS morphologies. METHODS: Using data from the Duke Echocardiography Laboratory Database, the study identified patients with baseline electrocardiography and LVEF ≤35% who had a follow-up LVEF 3 to 6 months later. The study excluded patients with severe valve disease, a cardiac device, left ventricular assist device, or heart transplant. QRS morphology was classified as LBBB, QRS duration <120 ms (narrow QRS duration), or a wide QRS duration ≥120 ms but not LBBB. Analysis of variance testing compared mean change in LVEF among the 3 groups with adjustment for significant comorbidities and GDMT. RESULTS: There were 659 patients that met the criteria: 111 LBBB (17%), 59 wide QRS duration ≥120 ms but not LBBB (9%), and 489 narrow QRS duration (74%). Adjusted mean increase in LVEF over 3 to 6 months in the 3 groups was 2.03%, 5.28%, and 8.00%, respectively (p < 0.0001). Results were similar when adjusted for interim revascularization and myocardial infarction. Comparison of mean LVEF improvement between patients with LBBB on GDMT and those not on GDMT showed virtually no difference (3.50% vs. 3.44%). The combined endpoint of heart failure hospitalization or mortality was highest for patients with LBBB. CONCLUSIONS: LBBB is associated with a smaller degree of LVEF improvement compared with other QRS morphologies, even with GDMT. Some patients with LBBB may benefit from CRT earlier than guidelines currently recommend.

Comparison of Incidence of Left Ventricular Systolic Dysfunction Among Patients With Left Bundle Branch Block Versus Those With Normal QRS Duration.

We compared the incidence of left ventricular systolic dysfunction (LVSD) among patients with left bundle branch block (LBBB) to a matched cohort of patients with a narrow QRS duration <120 ms (NQRS). We hypothesized patients with preserved ejection fraction (EF) ≥50% and LBBB would have higher incidence of LVSD compared with a matched population of NQRS patients. Patients with LBBB on electrocardiogram within 30 days of a baseline echocardiogram with EF ≥50%, who had at least 1 follow-up echocardiogram ≥6 months later, were matched 1:1 on risk factors for cardiomyopathy to patients with NQRS. Incident LVSD was defined as a decline in EF to ≤45% on follow-up echocardiogram, or heart transplant, receipt of a cardiac device for LVSD (defibrillator or biventricular pacemaker), or implantation of a left ventricular assist device ≥6 months post baseline echocardiogram. Relative risk was calculated using conditional Poisson regression techniques. The final study cohort consisted of 188 patients, 94 with LBBB and 94 with NQRS. On follow-up, progression to LVSD was noted in 36% of LBBB patients and 10% of NQRS patients. The relative risk for LVSD in patients with LBBB was 3.78 (95% confidence interval = 1.98 to 7.19). In conclusion, there is a strong association between LBBB and the subsequent development of LVSD independent of common risk factors for cardiomyopathy.

Pulmonary Vein Isolation Lesion Set Assessment During Radiofrequency Catheter Ablation for Atrial Fibrillation.

This article reviews methods for lesion set assessment during radiofrequency catheter ablation for atrial fibrillation (AF). Pulmonary vein isolation (PVI) is the foundation for AF ablation, but PV reconnection can lead to treatment failure. Testing for entrance block can help confirm PVI, although complex electrograms that consist of both near- and far-field potentials may make assessment of entrance block challenging. Differential pacing maneuvers can help appropriately identify PV potentials. After entrance block has been achieved, pacing within the PVs to demonstrate capture of PV musculature with exit block may also help to confirm completeness of lesion sets for PVI. Employing a waiting period of at least 30 min or administering adenosine or isoproterenol can reveal dormant conduction, warranting adjunctive ablation. Additional techniques to confirm durable PVI include testing the ablation lines for excitability with high amplitude pacing, and automated waveform analysis of local electrogram morphology. Newer techniques like real-time magnetic resonance imaging and acoustic radiation force impulse elastography may have a role in testing the completeness of lesion sets in the future.

Why the Authors Use Cardiac Resynchronization Therapy with Defibrillators.

Cardiac resynchronization therapy (CRT) improves left ventricular function, especially in patients with left bundle branch block or those receiving chronic right ventricular pacing. CRT is typically accomplished by placing a right ventricular endocardial pacing lead and a left ventricular pacing lead via the coronary sinus to a coronary vein overlying the lateral or posterolateral left ventricle. CRT can be combined with an implantable defibrillator or with a pacemaker. Limited data are available to compare these two versions of CRT head to head. This review summarizes the relevant trials and meta-analyses regarding these two forms of CRT.

Why the Authors Use Cardiac Resynchronization Therapy with Defibrillators.

Cardiac resynchronization therapy (CRT) improves left ventricular function, especially in patients with left bundle branch block or those receiving chronic right ventricular pacing. CRT is typically accomplished by placing a right ventricular endocardial pacing lead and a left ventricular pacing lead via the coronary sinus to a coronary vein overlying the lateral or posterolateral left ventricle. CRT can be combined with an implantable defibrillator or with a pacemaker. Limited data are available to compare these two versions of CRT head to head. This review summarizes the relevant trials and meta-analyses regarding these two forms of CRT.

A longitudinal, collaborative, practice-based learning and improvement model to improve post-discharge heart failure outcomes.

BACKGROUND: Practice-based learning and improvement is one of the Accreditation Council of Graduate Medical Education's core competencies fortrainees. Residencyprograms have grappled with how to accomplish this goal. AIM: We describe our institution's unique, longitudinal post-graduate year process and project. SETTING: West Haven, VA Medical Center. PARTICIPANTS: Yale University School of Medicine junior residents on ambulatory electives and faculty preceptor. PROGRAM DESCRIPTION: Longitudinal program aimed to decrease re-admissions for hospitalized patients with congestive heart failure. DISCUSSION: We feel that our longitudinal project is a novel innovation worthy of further study.

Relation between renal function and response to cardiac resynchronization therapy in Multicenter Automatic Defibrillator Implantation Trial--Cardiac Resynchronization Therapy (MADIT-CRT).

BACKGROUND: Cardiorenal interactions have been shown to affect outcome in heart failure patients but were not related to response to cardiac resynchronization therapy (CRT). OBJECTIVE: The purpose of this study was to test our hypothesis that assessment of markers of prerenal failure may help identify mildly symptomatic HF patients with diminished effective circulating blood volume who will benefit from CRT. METHODS: The benefit of CRT with a defibrillator (CRT-D) as compared with defibrillator-only therapy in reducing the risk of HF or death was assessed by renal function parameters (including serum creatinine [SCr], blood urea nitrogen [BUN], and the ratio of BUN to SCr [BUN:SCr], dichotomized at median values and into approximate quartiles) among 1,803 patients enrolled in the Multicenter Automatic Defibrillator Implantation Trial-Cardiac Resynchronization Therapy. RESULTS: Multivariate analysis showed that the benefit of CRT-D was inversely related to SCr levels and directly related to BUN levels. Combined assessment of the two renal function parameters showed a significant difference in the benefit of CRT-D between patients with low (≤ 18 mg/dL, HR = 0.85, P = .28) and elevated (> 18 mg/dL, HR = 0.46, P < .001) BUN:SCr (P-value for interaction = .005). Consistently, the benefit of CRT-D was significantly increased with increasing quartiles of BUN:SCr (Q(1): HR = 1.06 [P = .79], Q(2): HR = 0.64 [P = .04], Q(3): HR = 0.47 [P < .001], Q(4): HR = 0.44 [P < .001]; P-value for trend = .005). CONCLUSIONS: In MADIT-CRT, patients with an elevated ratio of BUN to SCr experienced a significantly greater reduction in the risk of HF or death with CRT-D therapy as compared with patients with a low ratio. These findings suggest an association between prerenal function and response to CRT.

Risk factors for recurrent heart failure events in the Multicenter Automatic Defibrillator Implantation Trial II (MADIT-II).

UNLABELLED: Risk Factors for Recurrent Heart Failure. BACKGROUND: This study was designed to identify risk factors for recurrent heart failure (HF) events in patients with ischemic left ventricular dysfunction enrolled in the Multicenter Automatic Defibrillator Implantation Trial II (MADIT-II). METHODS AND RESULTS: The Prentice, Williams, and Peterson (PWP) statistical model was utilized to identify and compare risk factors for 1 or ≥ 2 HF hospitalizations among 1,218 patients with ischemic left ventricular dysfunction enrolled in the MADIT-II trial. Risk factors for a first HF hospitalization included treatment with an ICD (HR = 1.31; P = 0.05), New York Heart Association class > II (HR = 1.95; P < 0.001), female gender (HR = 1.38; P = 0.05), atrial fibrillation (HR = 1.90; P = 0.001), QRS >120 ms (HR = 1.41; P = 0.01), diabetes mellitus (HR = 1.51; P = 0.003), heart rate ≥ 80 (HR = 1.35; P = 0.04), diuretic therapy (HR = 1.82; P < 0.001), and the presence of prerenal azotemia (defined as blood urea nitrogen:creatinine > 20; HR = 1.45; P = 0.01). In contrast, prerenal azotemia was the only risk factor that was independently associated with a significant increase in the risk of ≥ 2 HF hospitalizations (HR = 1.52; P = 0.027). The occurrence of 1 HF event after enrollment was associated with a 2.8-fold (P < 0.001) increase in the risk of death, whereas after the occurrence of a second event there was a 6.7-fold (P < 0.001) increase in the risk of subsequent mortality. CONCLUSIONS: In MADIT-II, prerenal azotemia was the only significant and independent risk factor for HF progression after a first event, and recurrent HF was the most powerful predictor of mortality. These findings stress the importance of identifying risk factors for HF progression among patients who receive an ICD for primary prevention.

Long QT syndrome in patients over 40 years of age: increased risk for LQTS-related cardiac events in patients with coronary disease.

BACKGROUND: Previous studies of long QT syndrome (LQTS) have focused primarily on the clinical course of affected patients up to 40 years of age to avoid the confounding influence of acquired heart disease on LQTS-related cardiac events in this genetic disorder. METHODS: Patients were identified as having coronary disease if they had a history of hospitalization for myocardial infarction, coronary angioplasty, coronary artery bypass graft surgery, or were treated with medication for angina. LQTS-related cardiac events included the first occurrence of syncope, aborted cardiac arrest, or sudden cardiac death without evidence suggestive of an acute coronary event. Cox proportional hazards regression modeling was used to analyze the independent contribution of coronary disease to LQTS-related cardiac events. RESULTS: Time-dependent coronary disease was associated with an increased risk of LQTS-related cardiac events (hazard ratio 2.24, 95% confidence interval 1.23-4.07, P = 0.008) after adjustment for syncopal history before age 40, QTc, and gender. Factors such as diabetes and hypertension that increase the risk for coronary disease were not associated with an increased risk for LQTS-related cardiac events. CONCLUSIONS: This is the first study to demonstrate that coronary disease augments the risk for LQTS-related cardiac events in LQTS. The findings highlight the need for more focused preventive therapy in LQTS patients above the age of 40.