Risk of Appropriate Implantable Cardioverter-Defibrillator Therapies and Sudden Cardiac Death in Patients With Heart Failure With Improved Left Ventricular Ejection Fraction.

BACKGROUND: The benefit of implantable cardioverter-defibrillator (ICD) therapy is controversial in patients who have heart failure with improved left ventricular ejection fraction (EF) to >35% after implantation (HFimpEF). METHODS: Databases (Ovid MEDLINE, EMBASE, Web of Science, and Google Scholar) were queried for studies in patients with ICD that reported the association between HFimpEF and arrhythmic events (AEs), defined as the combined incidence of ventricular arrhythmias, appropriate ICD intervention, and sudden cardiac death (primary composite end point). RESULTS: A total of 41 studies and 38,572 patients (11,135 with HFimpEF, 27,437 with persistent EF ≤35%) were included; mean follow-up was 43 months. HFimpEF was associated with decreased AEs (odds ratio [OR] 0.39, 95% confidence interval [CI] 0.32 to 0.47; annual rate [AR] 4.1% vs 8%, p <0.01). Super-responders (EF ≥50%) had less risk of AEs than did patients with more modest reverse remodeling (EF >35% and <50%, OR 0.25, 95% CI 0.14 to 0.46, AR 2.7% vs 6.2%, p <0.01). Patients with HFimpEF who had an initial primary-prevention indication had less risk of AEs (OR 0.43, 95% CI 0.3 to 0.61, AR 5.1% vs 10.3%, p <0.01). Among patients with primary prevention who had never received appropriate ICD therapy at the time of generator change, HFimpEF was associated with decreased subsequent AEs (OR 0.26, 95% CI 0.12 to 0.59, AR 1.6% vs 4.8%, p <0.01). In conclusion, HFimpEF is associated with reduced, but not eliminated, risk for AEs in patients with ICDs. The decision to replace an ICD in subgroups at less risk should incorporate shared decision making based on risks for subsequent AEs and procedural complications.

Association of late gadolinium enhancement in cardiac magnetic resonance with mortality, ventricular arrhythmias, and heart failure in patients with nonischemic cardiomyopathy: A systematic review and meta-analysis.

Background: Late gadolinium enhancement (LGE) on cardiac magnetic resonance is a predictor of adverse events in patients with nonischemic cardiomyopathy (NICM). Objective: This meta-analysis evaluated the correlation between LGE and mortality, ventricular arrhythmias (VAs) and sudden cardiac death (SCD), and heart failure (HF) outcomes. Methods: A literature search was conducted for studies reporting the association between LGE in NICM and the study endpoints. The primary endpoint was mortality. Secondary endpoints included VA and SCD, HF hospitalization, improvement in left ventricular ejection fraction (LVEF) to >35%, and heart transplantation referral. The search was not restricted to time or publication status. The minimum follow-up duration was 1 year. Results: A total of 46 studies and 10,548 NICM patients (4610 with LGE, 5938 without LGE) were included; mean follow-up was 3 years (range 13-71 months). LGE was associated with increased mortality (odds ratio [OR] 2.9; 95% confidence interval [CI] 2.3-3.8; P < .01) and VA and SCD (OR 4.6; 95% CI 3.5-6.0; P < .01). LGE was associated with an increased risk of HF hospitalization (OR 3.4; 95% CI 2.3-5.0; P < .01), referral for transplantation (OR 5.1; 95% CI 2.5-10.4; P < .01), and decreased incidence of LVEF improvement to >35% (OR 0.2; 95% CI 0.03-0.85; P = .03). Conclusion: LGE in NICM patients is associated with increased mortality, VA and SCD, and HF hospitalization and heart transplantation referral during long-term follow up. Given these competing risks of mortality and HF progression, prospective randomized controlled trials are required to determine if LGE is useful for guiding prophylactic implantable cardioverter-defibrillator placement in NICM patients.

Effects of GLP-1 Agonists on mortality and arrhythmias in patients with Type II diabetes.

Background: Glucagon-like Peptide-1 Receptor Agonists (GLP-1 RA) are frequently used for the management of diabetes. The impact of GLP-1 RA on cardiovascular outcomes is unclear. We aim to assess the effect of GLP-1 RA on mortality, atrial and ventricular arrhythmias, and sudden cardiac death in patients with type II diabetes. Methods: We searched databases including Ovid MEDLINE, EMBASE, Scopus, Web of Science, Google Scholar and CINAHL, from inception to May 2022, for randomized controlled trials reporting the relationship between GLP-1 RA (including albiglutide, dulaglutide, exenatide, liraglutide, lixisenatide, and semaglutide) and mortality, atrial arrhythmias, and the combined incidence of ventricular arrhythmias and sudden cardiac death. The search was not restricted to time or publication status. Results: A total of 464 studies resulted from literature search, of which 44 studies, including 78,702 patients (41,800 GLP-1 agonists vs 36,902 control), were included. Follow up ranged from 52 to 208 weeks. GLP-1 RA were associated with lower risk of all-cause mortality (odds ratio 0.891, 95% confidence interval 0.837-0.949; P < 0.01) and reduced cardiovascular mortality (odds ratio 0.88, 95% confidence interval 0.881-0.954; P < 0.01). GLP-1 RA were not associated with increased risk of atrial (odds ratio 0.963, 95% confidence interval 0.869-1.066; P 0.46) or ventricular arrhythmias and sudden cardiac death (odds ratio 0.895, 95% confidence interval 0.706-1.135; P 0.36). Conclusion: GLP-1 RA are associated with decreased all-cause and cardiovascular mortality, and no increased risk of atrial and ventricular arrhythmias and sudden cardiac death.

Prognostic value of late-gadolinium enhancement on cardiac magnetic resonance in patients with cardiac sarcoidosis.

BACKGROUND: Late-gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) is a predictor of adverse events in patients with cardiac sarcoidosis (CS), but available studies had small sample sizes and did not consider all relevant endpoints. OBJECTIVE: To evaluate the association between LGE on CMR in patients with CS and mortality, ventricular arrhythmias (VA) and sudden cardiac death (SCD), and heart failure (HF) hospitalization. METHODS: A literature search was conducted for studies reporting the association between LGE in CS and the study endpoints. The endpoints were mortality, VA and SCD, and HF hospitalization. The search included the following databases: Ovid MEDLINE, EMBASE, Web of Science, and Google Scholar. The search was not restricted to time or publication status. The minimum follow-up duration was 1 year. RESULTS: A total of 17 studies and 1915 CS patients (595 with LGE vs. 1320 without LGE) were included; mean follow-up was 3.3 years (ranging between 17 and 84 months). LGE was associated with increased all-cause mortality (OR 6.05, 95% CI 3.16-11.58; p < .01), cardiovascular mortality (OR 5.83, 95% CI 2.89-11.77; p < .01), and VA and SCD (OR 16.48, 95% CI 8.29-32.73; p < .01). Biventricular LGE was associated with increased VA and SCD (OR 6.11, 95% CI 1.14-32.68; p = .035). LGE was associated with an increased HF hospitalization (OR 17.47, 95% CI 5.54-55.03; p < .01). Heterogeneity was low: df = 7 (p = .43), I2 = 0%. CONCLUSIONS: LGE in CS patients is associated with increased mortality, VA and SCD, and HF hospitalization. Biventricular LGE is associated with an increased risk of VA and SCD.

Effect of Implanted Defibrillator on Mortality in Patients With Chronic Kidney Disease.

The beneficial role of implantable cardioverter defibrillators (ICDs) in patients with chronic kidney disease (CKD) is controversial. This meta-analysis aimed to evaluate the effect of ICD on mortality in patients with CKD. A literature search was conducted for studies reporting the effect of ICD on all-cause mortality in patients with CKD (estimated glomerular filtration rate <60 ml/min/1.73 m2). The search was not restricted to time or publication status. The search included the following databases: Ovid MEDLINE, EMBASE, Scopus, Web of Science, Google Scholar, and EBSCO CINAHL. The primary end point was all-cause mortality. The minimum duration of follow-up required for inclusion was 1 year. The literature search identified 834 studies, of which 14 studies with 70,661 patients were included. Mean follow-up was 39 months (12 to 81 months). For all patients with CKD, ICD was associated with lower all-cause mortality (log hazard ratio [HR] -0.247, standard error [SE] 0.101, p = 0.015). Heterogeneity: degree of freedom = 13 (p <0.01), I2 = 97.057; test for overall effect: Z = -2.431 (p = 0.015). When further stratified based on dialysis, patients with CKD without the need for dialysis had significantly lower mortality (log HR -0.211, SE 0.095, p = 0.026), with a similar trend in patients who underwent dialysis (log HR -0.262, SE 0.134, p = 0.051). ICD implantation is associated with a significant mortality benefit in patients with CKD.

Rhythm versus rate control for atrial fibrillation in heart failure with preserved ejection fraction.

Background: There are few prospective studies assessing the benefits of rhythm control of atrial fibrillation (AF) in patients with heart failure and preserved ejection fraction (HFpEF), which accounts for 50% of all heart failure patients. Objective: Conduct a meta-analysis to assess the effects of rhythm control (ablation and/or antiarrhythmic medications) vs rate control on all-cause mortality in AF patients with HFpEF. Methods: Databases were searched for studies reporting the effect of rhythm control vs rate control on mortality in patients with HFpEF (Ovid MEDLINE, EMBASE, Scopus, Web of Science, Google Scholar, and EBSCO CINAHL). The search was not restricted to time or publication status. The primary endpoint was all-cause mortality. The minimum duration of follow-up required for inclusion was 1 year. Results: The literature search identified 1210 candidate studies; 5 studies and 16,825 patients were included. The study population had 57% men with a mean age of 71± 2.5 years. Rhythm control for AF was associated with lower all-cause mortality (odds ratio 0.735, 95% confidence interval 0.665-0.813; P < .001) as compared to rate control. Conclusion: Rhythm control for AF in patients with HFpEF was associated with decreased all-cause mortality.

QT interval measurement in ventricular pacing: Implications for assessment of drug effects and pro-arrhythmia risk.

QT interval prolongation is a known risk factor for development of malignant ventricular arrhythmias. Measurement of the QT interval is difficult in the setting of ventricular pacing (VP), which can prolong depolarization and increase the QT interval, overestimating repolarization time. VP and cardiac resynchronization therapies have become commonplace in modern cardiac care and may contribute to repolarization heterogeneity and subsequent increased risk for ventricular arrhythmias including Torsades de Pointes. It is imperative for the clinician caring for acutely ill cardiac patients to understand the relationship between QT interval prolongation, both drug-induced and pacing-induced, and repolarization changes with subsequent ventricular arrhythmia risk. In this review, we discuss the components of QT interval assessment for arrhythmogenic risk including arrhythmogenic QT prolongation, methods for adjusting the QT interval to identify repolarization changes, methods to adjust for heart rate, and propose a framework for medication management to assess for drug-induced long QT syndrome in patients with VP.

Identification and Endocardial Ablation of the Ligament of Marshall for Pulmonary Vein Isolation.

OBJECTIVES: The aims of this study were to establish criteria for identifying ligament of Marshall (LOM) connections that are responsible for pulmonary vein isolation (PVI) failure, assess their incidence, and determine if they can be targeted by focal endocardial ablation at the anterior carina of the left superior pulmonary vein (LSPV). BACKGROUND: Wide antral ablation of the left pulmonary veins (PVs) may not achieve PVI, sometimes requiring empirical ablation of the PV carina. The mechanism could be due to epicardial conduction along the LOM, which courses adjacent to the anterior carina. METHODS: In patients undergoing radiofrequency ablation for atrial fibrillation, if wide ablation of the left PV did not achieve isolation, bidirectional mapping was performed. A presumptive LOM connection was diagnosed if the earliest entrance was mapped to the anterior LSPV, while the earliest exit was mapped inferior to the left inferior PV. Focal ablation at the LSPV anterior carina was performed, even if not at the site of earliest entrance activation. The primary endpoint was successful PVI immediately after ablation. RESULTS: The study included 455 consecutive patients who underwent 570 procedures, of which 364 were first-time ablations. Presumptive LOM connections were identified in 48 procedures (8.4%) and in 41 patients (11.2%) undergoing first-time ablation and were successfully ablated at the anterior carina of the LSPV in 47 of 48 procedures (98%). CONCLUSIONS: LOM connections may be a common cause of PVI failure and can be easily identified and reliably ablated with focal endocardial ablation at the anterior LSPV carina.

Electrical Storm in a Case of Bilateral Pheochromocytomas.

BACKGROUND Pheochromocytomas are catecholamine-secreting tumors that develop within the chromaffin cells of the adrenal glands. They most commonly present with hypertension, and the classic triad of symptoms is headaches, palpitations, and diaphoresis. Electrical storm (ES) is defined as at least 3 sustained episodes of ventricular tachycardia (VT), ventricular fibrillation (VF), or appropriate shocks from an implanted cardioverter-defibrillator (ICD) within 24 h. We discuss the case of a 63-year-old man with known bilateral pheochromocytomas who presented with ES prompting multiple ICD shocks, possibly exacerbated by catecholamine surge from his adrenal tumors. CASE REPORT The patient was a 63-year-old man with an extensive medical history including ischemic cardiomyopathy and congestive heart failure with reduced ejection fraction presented with multiple syncopal episodes secondary to persistent monomorphic ventricular tachycardia (MMVT), polymorphic ventricular tachycardia (PMVT), and VF requiring ICD shocks. He had known bilateral pheochromocytomas. ES was attributed to catecholamine excess in the setting of these tumors, so VT ablation was deferred pending tumor removal. Alpha blockade was initiated preoperatively, and the patient subsequently underwent bilateral adrenalectomy; however, he continued to sustain tachyarrhythmias and eventually died despite resuscitative efforts. CONCLUSIONS Bilateral pheochromocytomas are rare adrenal tumors. In even more infrequent situations, they can cause ES secondary to adrenergic stimulation from catecholamine surges. It is worth considering pheochromocytoma in patients with refractory ES, as treating these tumors could potentially reduce the frequency of this dangerous arrhythmia.

Impact of wearable cardioverter-defibrillator compliance on outcomes in the VEST trial: As-treated and per-protocol analyses.

BACKGROUND: Vest Prevention of Early Sudden Death Trial did not demonstrate a significant reduction in arrhythmic death with the wearable cardioverter-defibrillator (WCD), but compliance with the device may have substantially affected the results. ThePletcher influence of WCD compliance on outcomes has not yet been fully evaluated. METHODS: Using linear and pooled logistic models, we performed as-treated analyses omitting person-time in the hospital and adjusted for correlates of WCD compliance. To assess the impact of early stopping of WCD, we performed a per-protocol Kaplan-Meier analysis, censoring after the last day the WCD was worn. Interactions of potential effect modifiers with treatment assignment and WCD compliance on outcomes were investigated. Finally, we used linear models to identify predictors of WCD compliance. RESULTS: A per-protocol analysis demonstrated a significant reduction in total (P < .001) and arrhythmic (P = .001) mortality. Better WCD compliance was independently predicted by cardiac arrest during index myocardial infarction (MI), higher Cr, diabetes, prior heart failure, EF ≤ 25%, Polish enrolling center and number of WCD alarms, while worse compliance was predicted by being divorced, Asian race, higher body mass index, prior percutaneous coronary intervention, or any WCD shock. Neither excluding time in hospital from the as-treated analysis nor adjustment for factors affecting WCD compliance materially changed the results. No variable demonstrated a significant interaction in either the intention-to-treat or as-treated analysis. CONCLUSION: Robust sensitivity analyses of as-treated and per-protocol analyses suggest that the WCD is protective in compliant patients with ejection fraction less than or equal to 35% during the first 3 months post-MI.

Wearable Cardioverter-Defibrillator after Myocardial Infarction.

BACKGROUND: Despite the high rate of sudden death after myocardial infarction among patients with a low ejection fraction, implantable cardioverter-defibrillators are contraindicated until 40 to 90 days after myocardial infarction. Whether a wearable cardioverter-defibrillator would reduce the incidence of sudden death during this high-risk period is unclear. METHODS: We randomly assigned (in a 2:1 ratio) patients with acute myocardial infarction and an ejection fraction of 35% or less to receive a wearable cardioverter-defibrillator plus guideline-directed therapy (the device group) or to receive only guideline-directed therapy (the control group). The primary outcome was the composite of sudden death or death from ventricular tachyarrhythmia at 90 days (arrhythmic death). Secondary outcomes included death from any cause and nonarrhythmic death. RESULTS: Of 2302 participants, 1524 were randomly assigned to the device group and 778 to the control group. Participants in the device group wore the device for a median of 18.0 hours per day (interquartile range, 3.8 to 22.7). Arrhythmic death occurred in 1.6% of the participants in the device group and in 2.4% of those in the control group (relative risk, 0.67; 95% confidence interval [CI], 0.37 to 1.21; P=0.18). Death from any cause occurred in 3.1% of the participants in the device group and in 4.9% of those in the control group (relative risk, 0.64; 95% CI, 0.43 to 0.98; uncorrected P=0.04), and nonarrhythmic death in 1.4% and 2.2%, respectively (relative risk, 0.63; 95% CI, 0.33 to 1.19; uncorrected P=0.15). Of the 48 participants in the device group who died, 12 were wearing the device at the time of death. A total of 20 participants in the device group (1.3%) received an appropriate shock, and 9 (0.6%) received an inappropriate shock. CONCLUSIONS: Among patients with a recent myocardial infarction and an ejection fraction of 35% or less, the wearable cardioverter-defibrillator did not lead to a significantly lower rate of the primary outcome of arrhythmic death than control. (Funded by the National Institutes of Health and Zoll Medical; VEST ClinicalTrials.gov number, NCT01446965 .).

Haptics and the heart: Force and tactile feedback system for cardiovascular interventions.

BACKGROUND/PURPOSE: Interventional cardiovascular procedures are performed while operators view multiple visual displays including fluoroscopic and ultrasonic images, intracardiac electrical signals, electroanatomic mapping data, and hemodynamic indices. Operators are unable to palpate physiologic and biophysical signals or feel intracardiac anatomy due to the attenuation and dampening properties of cardiac catheters. This poses a significant limitation when performing higher risk procedures such as complex coronary interventions, transeptal or epicardial puncture to gain access to the left atrium or pericardium for ablation of heart rhythm disorders, cardiac device delivery, and when attempting to maintain stable tissue contact force ("CF") during ablation of cardiac arrhythmia. METHODS/MATERIALS: We utilized signals acquired from a prototype sensorized cardiac guiding catheter, conventional transeptal puncture kit with end hole manometry, commercially available contact force sensing ablation catheter, and epicardial puncture needle, input these signals into a novel signal processing system and generated palpable sensations to blinded subjects using a proprietary tactile/force (haptic) feedback system. Qualitative and quantitative analysis of the system was performed. RESULTS/CONCLUSION: The proprietary haptic (tactile and force) feedback system provides sense of touch during cardiovascular interventions recreating palpable, real-time biophysical events and physiologic information and enables operators to react to critical cardiovascular signals with minimal delay relative to visual motor reaction time to simple display data. SUMMARY: We describe a proprietary haptic (tactile and force) feedback system that provides sense of touch during cardiovascular interventions recreating palpable, real-time biophysical events and physiologic information.

Mercury, omega-3 fatty acids, and seafood intake are not associated with heart rate variability or QT interval.

Mercury (Hg), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) concentrations differ across seafood types. Our aim was to investigate the association of Hg, EPA, and DHA, as well as avid consumption of diverse seafood types, with cardiovascular variables heart rate variability (HRV) and QT interval duration (QTc) in a contemporary population. We measured HRV and QTc by Holter monitor, EPA and DHA in plasma, total Hg in whole blood, and possible confounders in 94 avid seafood consumers from Long Island, NY. Participants had mean Hg of 8.4 mcg/L, mean EPA of 1.2%, and mean DHA of 3.7% of total fatty acids. Adjusted for possible confounders, EPA+DHA, Hg, and total seafood consumption were not associated with HRV or QTc. Associations with consumption of specific seafood types were suggested (eg, tuna steak with QTc and anchovies with HRV) but require verification.

Syncope, seizure or both?

Ictal asystole (IA) is a rare phenomenon in patients with seizures with an incidence of 0.27-0.4% and has been proposed as a possible mechanism of sudden unexpected death in epilepsy patients (SUDEP). We present a case of a 53-year-old woman who initially presented with episodes of expressive aphasia and was treated with antiepileptic drugs (AEDs). While on therapy she experienced episodes of syncope. During her hospitalization for tapering of AEDs and 24-hour EEG monitoring, the patient developed a seizure followed by sinus bradycardia and an 18-second sinus pause, resulting in loss of consciousness and slowing of cerebral activity. Ten seconds after the return of cardiac activity, the EEG showed return of cerebral activity. A dual chamber pacemaker was implanted.