Predicting Malignant Ventricular Arrhythmias Using Real-Time Remote Monitoring.

BACKGROUND: Although implantable cardioverter-defibrillator (ICD) therapies are associated with increased morbidity and mortality, the prediction of malignant ventricular arrhythmias has remained elusive. OBJECTIVES: The purpose of this study was to evaluate whether daily remote-monitoring data may predict appropriate ICD therapies for ventricular tachycardia or ventricular fibrillation. METHODS: This was a post hoc analysis of IMPACT (Randomized trial of atrial arrhythmia monitoring to guide anticoagulation in patients with implanted defibrillator and cardiac resynchronization devices), a multicenter, randomized, controlled trial of 2,718 patients evaluating atrial tachyarrhythmias and anticoagulation for patients with heart failure and ICD or cardiac resynchronization therapy with defibrillator devices. All device therapies were adjudicated as either appropriate (to treat ventricular tachycardia or ventricular fibrillation) or inappropriate (all others). Remote monitoring data in the 30 days before device therapy were utilized to develop separate multivariable logistic regression and neural network models to predict appropriate device therapies. RESULTS: A total of 59,807 device transmissions were available for 2,413 patients (age 64 ± 11 years, 26% women, 64% ICD). Appropriate device therapies (141 shocks, 10 antitachycardia pacing) were delivered to 151 patients. Logistic regression identified shock lead impedance and ventricular ectopy as significantly associated with increased risk of appropriate device therapy (sensitivity 39%, specificity 91%, AUC: 0.72). Neural network modeling yielded significantly better (P < 0.01 for comparison) predictive performance (sensitivity 54%, specificity 96%, AUC: 0.90), and also identified patterns of change in atrial lead impedance, mean heart rate, and patient activity as predictors of appropriate therapies. CONCLUSIONS: Daily remote monitoring data may be utilized to predict malignant ventricular arrhythmias in the 30 days before device therapies. Neural networks complement and enhance conventional approaches to risk stratification.

Impact of physiological pacing on functional mitral regurgitation in systolic dysfunction: Initial echocardiographic remodeling findings after His bundle pacing.

BACKGROUND: Although His bundle pacing (HBP) has been shown to improve left ventricular ejection fraction (LVEF), its impact on mitral regurgitation (MR) remains uncertain. OBJECTIVES: The aim of this study was to evaluate change in functional MR after HBP in patients with left ventricular (LV) systolic dysfunction. METHODS: Paired echocardiograms were retrospectively assessed in patients with reduced LVEF (<50%) undergoing HBP for pacing or resynchronization. The primary outcomes assessed were change in MR, LVEF, LV volumes, and valve geometry pre- and post-HBP. MR reduction was characterized as a decline in ≥1 MR grade post-HBP in patients with ≥grade 3 MR at baseline. RESULTS: Thirty patients were analyzed: age 68 ± 15 years, 73% male, LVEF 32% ± 10%, 38% coronary artery disease, 33% history of atrial fibrillation. Baseline QRS was 162 ± 31 ms: 33% left bundle branch block, 37% right bundle branch block, 17% paced, and 13% narrow QRS. Significant reductions in LV end-systolic volume (122 mL [73-152 mL] to 89 mL [71-122 mL], P = .006) and increase in LV ejection fraction (31% [25%-37%] to 39% [30%-49%], P < .001) were observed after HBP. Ten patients had grade 3 or 4 MR at baseline, with reduction in MR observed in 7. In patients with at least grade 3 MR at baseline, reduction in LV volumes, improved mitral valve geometry, and greater LV contractility were associated with MR reduction. Greater reduction in paced QRS width was present in MR responders compared to non-MR responders (-40% vs -25%, P = .04). CONCLUSIONS: In this initial detailed echocardiographic analysis in patients with LV systolic dysfunction, HBP reduced functional MR through favorable ventricular remodeling.

Spatial and transmural properties of the reentrant ventricular tachycardia circuit in arrhythmogenic right ventricular cardiomyopathy: Simultaneous epicardial and endocardial recordings.

BACKGROUND: While advances in the characterization of the structural substrate in arrhythmogenic right ventricular cardiomyopathy (ARVC) have been made, the ventricular tachycardia (VT) circuit remains incompletely described. OBJECTIVE: The purpose of this study was to delineate the reentrant VT circuit with simultaneous epicardial and endocardial mapping (SEEM) in ARVC. METHODS: Twenty-three consecutive patients with ARVC and VT underwent SEEM at 4 centers between 2014 and 2020. Retrospective analysis was performed on combined isochronal activation maps. RESULTS: Of the 30 VT circuits, 24 were delineated with SEEM (956 [341-1843] endocardial points and 1763 [882-3054] epicardial points). The apex and outflow tract rarely harbored VT circuits, with 50% distributed in the inferior wall and 43% in the free wall. The entire tachycardia cycle length was recorded from the epicardium in 71% of circuits. In all circuits, a large proportion of the tachycardia cycle length was recorded from the epicardium relative to the endocardium. Localized epicardial reentry was observed in 35% of patients (14 mm × 15 mm), which was associated with smaller endocardial low voltage area (39 cm2 vs 104 cm2; P = .002) and preserved right ventricular ejection fraction (35% vs 25%; P = .046) compared with those with larger circuit dimensions. Seventy percent of termination sites were achieved from the epicardium. CONCLUSION: High-resolution recordings from both myocardial surfaces confirm a consistent predominance of epicardial participation during reentry in ARVC. Only the perivalvular inflow region of the "triangle of dysplasia" had a strong propensity to harbor VT circuits, with the greatest proportion located in the inferior wall. Localized epicardial reentry may be a manifestation of earlier stage disease with a relative paucity of endocardial substrate.

Left ventricle and mitral valve reverse remodeling in response to cardiac resynchronization therapy in nonischemic cardiomyopathy.

BACKGROUND: Cardiac resynchronization therapy (CRT) improves left heart geometry and function in nonischemic cardiomyopathy (NICMP). We aimed to detail the effects of CRT on left ventricular (LV) and mitral valve (MV) remodeling using 2-dimensional transthoracic echocardiography. METHODS: Forty-five consecutive patients with NICMP who underwent CRT implantation between 2009 and 2012, and had pre-CRT and follow-up echocardiograms available, were included. Paired t test, linear and logistic regression, and Kaplan-Meier survival analyses were used for statistical assessment. RESULTS: The mean age and QRS duration were 60 years and 157 ms, respectively, and 13 (28.9%) were female. At a mean follow-up of 3 years, there were 22 (48.9%) "CRT responders" (≥15% reduction in LV end-systolic volume index [LVESVi]). Significant improvements were observed in LV ejection fraction (26.3% vs 34.3%) and LVESVi (87.7 vs 71.1 mL/m2 ), as well as mitral regurgitation vena contracta width, MV tenting height and area, and end-systolic interpapillary muscle distance. Five-year actuarial survival was 87.5%. Multivariate regression analyses revealed the pre-CRT LVESVi (ß = 0.52), and MV coaptation length (ß = -0.34) and septolateral annular diameter (ß = 0.25) as good correlates of follow-up LVESVi. Variables associated with CRT response were pre-CRT MV coaptation length (OR 1.75, 95% CI 1.0-3.1) and posterior leaflet tethering angle (OR 1.07, 95% CI 1.0-1.14), irrespective of baseline QRS morphology and duration (all P < .05). CONCLUSIONS: Cardiac resynchronization therapy improves LV and MV geometry and function in half of patients with NICMP, which is paralleled by decreased mitral regurgitation severity. The extent of pre-CRT LV remodeling and MV tethering are associated with CRT response.

Preventing Postoperative Atrial Fibrillation After Noncardiac Surgery: A Meta-analysis.

BACKGROUND: Although postoperative atrial fibrillation is common after noncardiac surgery, there is a paucity of data regarding prophylaxis. We sought to determine whether pharmacologic prophylaxis reduces the incidence of postoperative atrial fibrillation after noncardiac surgery. METHODS: We performed an electronic search of Ovid MEDLINE, the Cochrane central register of controlled trials database, and SCOPUS from inception to September 7, 2016 and included prospective randomized studies in which patients in sinus rhythm underwent noncardiac surgery and examined the incidence of postoperative atrial fibrillation as well as secondary safety outcomes. RESULTS: Twenty-one studies including 11,608 patients were included. Types of surgery included vascular surgery (3465 patients), thoracic surgery (2757 patients), general surgery (2292 patients), orthopedic surgery (1756 patients), and other surgery (1338 patients). Beta-blockers (relative risk [RR] 0.32; 95% confidence interval [CI], 0.11-0.87), amiodarone (RR 0.42; 95% CI, 0.26 to 0.67), and statins (RR 0.43; 95% CI, 0.27 to 0.68) reduced postoperative atrial fibrillation compared with placebo or active controls. Calcium channel blockers (RR 0.55; 95% CI, 0.30 to 1.01), digoxin (RR 1.62; 95% CI, 0.95 to 2.76), and magnesium (RR 0.73; 95% CI, 0.23 to 2.33) had no statistically significant effect on postoperative atrial fibrillation incidence. The incidence of adverse events was comparable across agents, except for increased mortality (RR 1.33; 95% CI, 1.03 to 1.37) and bradycardia (RR 2.74; 95% CI, 2.19 to 3.43) in patients receiving beta-blockers. CONCLUSIONS: Pharmacologic prophylaxis with amiodarone, beta-blockers, or statins reduces the incidence of postoperative atrial fibrillation after noncardiac surgery. Amiodarone and statins have a relatively low overall risk of short-term adverse events.

Progressive ventricular dysfunction among nonresponders to cardiac resynchronization therapy: baseline predictors and associated clinical outcomes.

BACKGROUND: Cardiac resynchronization therapy (CRT) nonresponders have poor outcomes. The significance of progressive ventricular dysfunction among nonresponders remains unclear. OBJECTIVE: We sought to define predictors of and clinical outcomes associated with progressive ventricular dysfunction despite CRT. METHODS: We conducted an analysis of 328 patients undergoing CRT with defibrillator for standard indications. On the basis of 6-month echocardiograms, we classified patients as responders (those with a ≥5% increase in ejection fraction) and progressors (those with a ≥5% decrease in ejection fraction), and all others were defined as nonprogressors. Coprimary end points were 3-year (1) heart failure, left ventricular assist device (LVAD), transplantation, or death and (2) ventricular tachycardia (VT) or ventricular fibrillation (VF). RESULTS: Multivariable predictors of progressive ventricular dysfunction were aldosterone antagonist use (hazard ratio [HR] 0.23; P = .008), prior valve surgery (HR 3.3; P = .005), and QRS duration (HR 0.98; P = .02). More favorable changes in ventricular function were associated with lower incidences of heart failure, LVAD, transplantation, or death (70% vs 54% vs 33%; P < .0001) and VT or VF (66% vs 38% vs 28%; P = .001) for progressors, nonprogressors, and responders, respectively. After multivariable adjustment, progressors remained at increased risk of heart failure, LVAD, transplantation, or death (HR 2.14; P = .0029) and VT or VF (HR 2.03; P = .046) as compared with nonprogressors. Responders were at decreased risk of heart failure, LVAD, transplantation, or death (HR 0.44; P < .0001) and VT or VF (0.51; P = .015) as compared with nonprogressors. CONCLUSION: Patients with progressive deterioration in ventricular function despite CRT represent a high-risk group of nonresponders at increased risk of worsened clinical outcomes.

Does prior valve surgery change outcome in patients treated with cardiac resynchronization therapy?

AIMS: Cardiac valve surgery (CVS) has been implicated as a potential barrier to optimal response after cardiac resynchronization therapy (CRT) though prospective data regarding outcome remains limited. We sought to determine CRT response in patients with a prior history of CVS. METHODS AND RESULTS: We performed a retrospective analysis of a prospectively acquired cohort of CRT patients with history of CVS. Echocardiographic response was evaluated at baseline and 6 months. The coprimary endpoints were time to first heart failure (HF) hospitalization and a composite of all-cause mortality, transplantation and left ventricular assist device (LVAD) assessed over a 3-year follow-up period. The study group consisted of 569 patients undergoing CRT. Of these, 86 patients had a history of CVS (46.5% aortic, 37.2% mitral, 16.3% combined, and tricuspid), and were compared to 483 patients with no history of CVS. Baseline clinical and echocardiographic characteristics were not significantly different between the groups except for a higher incidence of atrial fibrillation (AF; 74.4% vs. 55.3%; P = 0.001), coronary artery bypass surgery (CABG; 58.1% vs. 38.7%; P = 0.001), and longer QRS duration (167.6 ± 29.3 milliseconds vs. 159.4 ± 27.5 milliseconds; P = 0.01) in those with prior CVS. Survival with respect to HF hospitalization and composite outcome was comparable in both groups. Echocardiographic response (improvement in left ventricular ejection fraction of ≥10%) was similar. No difference in clinical or echocardiographic outcome was found by type of valve surgery performed. CONCLUSION: Despite a higher incidence of AF, CABG, and longer QRS duration, history of CVS is not associated with worse clinical or echocardiographic outcome after CRT.

Meta-analysis of stem cell therapy in chronic ischemic cardiomyopathy.

Studies investigating bone marrow stem cell therapy (BMSCT) in patients with chronic ischemic cardiomyopathy have yielded mixed results. A meta-analysis of randomized controlled trials of BMSCT in patients with chronic ischemic cardiomyopathy was undertaken to assess its efficacy and the best route of administration. The MEDLINE, Embase, Cumulative Index to Nursing & Allied Health Literature, and Cochrane Library databases were searched through April 2012 for randomized controlled trials that investigated the impact of BMSCT and its route of administration on left ventricular (LV) function in patients with chronic ischemic cardiomyopathy and systolic dysfunction. Of the 226 reports identified, 10 randomized controlled trials including 519 patients (average LV ejection fraction [LVEF] at baseline 32 ± 7%) were included in the analysis. On the basis of a random-effects model, BMSCT improved the LVEF at 6 months by 4.48% (95% confidence interval [CI] 2.43% to 6.53%, p = 0.0001). A greater improvement in the LVEF was seen with intramyocardial injection compared with intracoronary infusion (5.13% [95% CI 3.17% to 7.10%], p <0.00001, vs 2.32% [95% CI -2.06% to 6.70%], p = 0.30). Overall, there were reductions in LV end-systolic volume of -20.64 ml (95% CI -33.21 to -8.07, p = 0.001) and LV end-diastolic volume of -16.71 ml (95% CI -31.36 to -2.06, p = 0.03). In conclusion, stem cell therapy may improve LVEF and favorably remodel the heart in patients with chronic ischemic cardiomyopathy. On the basis of current limited data, intramyocardial injection may be superior to intracoronary infusion in patients with LV systolic dysfunction.

Atrioventricular nodal ablation in atrial fibrillation: a meta-analysis and systematic review.

BACKGROUND: In the treatment of patients with refractory atrial fibrillation (AF), the safety and efficacy of atrioventricular nodal ablation (AVNA) versus pharmacotherapy alone remains unclear. Additionally, the impact of AVNA in patients with reduced systolic function is of growing interest. METHODS AND RESULTS: A total of 5 randomized or prospective trials were included for efficacy review (314 patients), 11 studies for effectiveness review (810 patients), and 47 studies for safety review (5632 patients). All-cause mortality was similar between AVNA and medical therapy (3.1% versus 3.3%; relative risk ratio, 1.05; 95% confidence interval [CI], 0.29-3.85). There was no significant difference in exercise duration or ejection fraction (EF) with AVNA relative to pharmacotherapy. In subgroup analysis, patients with baseline systolic dysfunction (116 patients; mean EF, 44%) showed significant relative improvement in EF after AVNA (+4% greater; 95% CI, 3.11-4.89). In pooled observational analysis, AVNA was also associated with significant improvement in EF only in patients with systolic dysfunction (+7.44%; 95% CI, 5.4-9.5). The incidence of procedure-related mortality (0.27%) and malignant arrhythmia (0.57%) was low. At mean follow-up of 26.5 months, the incidence of sudden cardiac death after AVNA was 2.1%. There was significant heterogeneity in quality-of-life scales used; compared with pharmacotherapy, AVNA was associated with significant improvement in several symptoms (palpitations, dyspnea). CONCLUSIONS: In the management of refractory AF, AVNA is associated with improvement in symptoms and quality of life, with a low incidence of procedure morbidity. In patients with reduced systolic function, AVNA demonstrates small but significantly improved echocardiographic outcomes relative to medical therapy alone.

Pulmonary vein isolation with complex fractionated atrial electrogram ablation for paroxysmal and nonparoxysmal atrial fibrillation: A meta-analysis.

BACKGROUND: Pulmonary vein isolation (PVI) is recognized as a potentially curative treatment for atrial fibrillation (AF). Ablation of complex fractionated atrial electrograms (CFAEs) in addition to PVI has been advocated as a means to improve procedural outcomes, but the benefit remains unclear. OBJECTIVE: This study sought t synthesize the available data testing the incremental benefit of adding CFAE ablation to PVI. METHODS: We performed a meta-analysis of controlled studies comparing the effect of PVI with CFAE ablation vs. PVI alone in patients with paroxysmal and nonparoxysmal AF. RESULTS: Of the 481 reports identified, 8 studies met our inclusion criteria. There was a statistically significant increase in freedom from atrial tachyarrhythmia (AT) with the addition of CFAE ablation (relative risk [RR] 1.15, P = .03). In the 5 reports of nonparoxysmal AF (3 randomized controlled trials, 1 controlled clinical trial, and 1 trial using matched historical controls), addition of CFAE ablation resulted in a statistically significant increase in freedom from AT (n = 112 of 181 [62%] for PVI+CFAE vs. n = 84 of 179 [47%] for PVI alone; RR 1.32, P = .02). In trials of paroxysmal AF (3 randomized controlled trials and 1 trial using matched historical controls), addition of CFAE ablation did not result in a statistically significant increase in freedom from AT (n = 131 of 166 [79%] for PVI+CFAE vs. n = 122 of 164 [74%] for PVI alone; RR 1.04, P = .52). CONCLUSION: In these studies of patients with nonparoxysmal AF, addition of CFAE ablation to PVI results in greater improvement in freedom from AF. No additional benefit of this combined approach was observed in patients with paroxysmal AF.

Side-to-side isoperistaltic strictureplasty in the treatment of extensive Crohn's disease.

BACKGROUND: First performed in 1992, the side-to-side isoperistaltic strictureplasty (SSIS) is a bowel-sparing surgical option for Crohn's patients presenting with sequentially occurring stenoses over long intestinal segments (>15 cm). This investigation was designed to study the outcomes and patterns of recurrence after a SSIS. MATERIALS AND METHODS: Between 1992 and 2003, 30 patients underwent SSIS at the University of Chicago. Their data were gathered prospectively in an Institutional Review Board-approved database. RESULTS: A total of 31 SSISs were constructed in 30 patients. As an indication of the severity of disease in these patients, 25 of 30 (83%) required a concomitant bowel resection, and 13 (43%) underwent at least one additional strictureplasty. The average length of diseased bowel used to construct the SSIS was 51 cm. The average length of residual small bowel after performance of SSIS was 275 cm, and the SSIS represented an average 19% of the remaining small bowel that would have otherwise been sacrificed with resection. Three patients experienced perioperative complications (10%) and one died (3%). Seven patients (23%) required reoperation to treat recurrence of symptoms within the first 5 years. In four of these patients, recurrence was found at or near the previous SSIS. CONCLUSIONS: A side-to-side isoperistaltic strictureplasty (SSIS) is a safe and effective surgical option for sequentially occurring Crohn's strictures over long intestinal segments.