Association of device detected atrial and ventricular tachyarrhythmia with adverse events in patients with an implantable cardioverter-defibrillator.

INTRODUCTION: Heart failure patients with a history of atrial fibrillation (AF) and ventricular tachycardia/ventricular fibrillation (VT/VF) are known to have worse outcomes. However, there are limited data on the temporal relationship between development of these arrhythmias and the risk of subsequent congestive heart failure (CHF) exacerbation and death. METHODS: The study cohort comprised 5511 patients implanted with an implantable cardioverter-defibrillator (ICD) in landmark clinical trials (MADIT-II, MADIT-RISK, MADIT-CRT, MADIT-RIT, and RAID) who were in sinus rhythm at enrollment. Multivariate cox analysis was performed to evaluate the time-dependent association between development of in-trial device detected AF and VT/VF with subsequent CHF exacerbation and death. RESULTS: Multivariate analysis showed that AF occurrence and VT/VF occurrence were both associated with a similar magnitude of risk for subsequent CHF exacerbation (HR = 1.73 and 1.87 respectively, p < .001 for both). In contrast, only in-trial VT/VF was associated with a significant > two-fold increase in the risk of subsequent mortality (HR = 2.13, p < .001) whereas AF occurrence was not associated with a significant mortality increase after adjustment for in-trial VT/VF (HR = 1.36, p = .096). CONCLUSION: Our findings from a large cohort of ICD recipients enrolled in landmark clinical trials show that device detected AF and VT/VF can be used to identify patients with increased risk for CHF exacerbation and mortality. These findings suggest a need for early intervention in CHF patients who develop device-detected atrial and ventricular tachyarrhythmias.

Exercise induced complete atrioventricular block: Utility of exercise stress test.

Exercise induced complete atrioventricular block (EIAVB) is a relatively uncommon condition. This phenomenon is clinically important because it can mimic symptoms of other cardiovascular conditions and may be associated with exercise intolerance and subsequent syncope. A 76year old man with long-standing hypertension and diabetes mellitus presented with recurrent episodes of lightheadedness and syncope with physical activity. ECG showed sinus rhythm with first degree atrioventricular block. Echocardiography did not show any valvular disease causing his symptoms. Coronoary angiographic evaluation revealed non-obstructive coronary artery disease. Because of the exertional nature of his symptoms, a symptom-limited treadmill exercise test was performed which revealed EIAVB. A permanent dual chamber pacemaker was implanted and his symptoms resolved completely.

Digoxin and Risk of Ventricular Tachyarrhythmia and Death in ICD Recipients.

BACKGROUND: Some studies have shown digoxin use to be associated with adverse outcomes, including increased mortality. There are limited data on whether digoxin use is associated with increased risk of ventricular tachycardia/ventricular fibrillation (VT/VF) in heart failure patients with an implantable cardioverter-defibrillator (ICD). OBJECTIVES: This study sought to assess whether digoxin use is associated with increased risk of VT/VF in patients with heart failure with reduced ejection fraction with a primary prevention ICD in landmark clinical trials. METHODS: The study cohort consisted of patients with an ICD or cardiac resynchronization therapy-defibrillator who were enrolled in 4 landmark MADIT trials (Multicenter Automatic Defibrillator Implantation Trials). We employed propensity score quintile stratification for treatment with digoxin as well as additional multivariable adjustment to assess the risk of digoxin vs no-digoxin therapy for the endpoints of first and recurrent VT/VF and all-cause mortality. The proportional hazards regression models for arrhythmia-specific endpoints incorporated adjustments for the competing risk of death. RESULTS: At baseline, 1,155 of 4,499 patients were on digoxin (26%). After propensity score quintile stratification, patients prescribed digoxin were shown to exhibit a statistically significant 48% increased risk of VT/VF (P < 0.001), 42% increased risk of the composite of VT/VF or death (P < 0.001), and a 37% increased risk of all-cause mortality (P = 0.006). Digoxin use was also associated with increased risk of appropriate ICD shocks (HR: 1.91; P < 0.001) and with increased burden of VT/VF events (HR: 1.46; P = 0.001). CONCLUSIONS: Our findings suggests that digoxin use is associated with ventricular tachyarrhythmia and death in heart failure with reduced ejection fraction patients with an ICD.

Recurrent ventricular tachycardia in a patient with COVID-19 vaccine-associated myocarditis: a case report.

Background: The development of coronavirus disease 2019 (COVID-19) vaccine-associated myocarditis has been reported. Most of the reported cases are mild, with quick clinical recovery and excellent short-term outcomes. Cases of COVID-19 vaccine-associated myocarditis presenting with sustained ventricular tachycardia (VT) are rare. Case Description: A 46-year-old male patient with no prior cardiac history presented following two episodes of syncope. Two days earlier, he had received his second dose of COVID-19 mRNA vaccine (Pfizer)-first dose was administered three weeks earlier. He had an episode of VT while in the emergency room. His cardiac magnetic resonance imaging (MRI) findings were consistent with myocarditis. He was eventually diagnosed with COVID-19 vaccine-associated myocarditis after all other work up were unremarkable [echocardiogram, coronary angiogram, diagnostic electrophysiology study and later 18F-fluorodeoxyglucose (FDG) metabolism cardiac sarcoid positron emission tomography (PET) study]. An implantable cardiac monitor was implanted to monitor for recurrence of VT. Seven months after initial presentation, he had recurrent VT and he underwent implantation of an implantable cardioverter defibrillator (ICD). He has received appropriate ICD therapies on account of recurrent VT and he is currently maintained on an antiarrhythmic medication. Conclusions: Excellent short-term outcomes have been reported in patients with COVID-19 vaccine associated myocarditis. Our case shows that long-term outcomes may not be benign in everyone, particularly in those who develop myocardial scar.

Risk of New-Onset Atrial Fibrillation Associated With Targeted Treatment of Lymphoma.

Background: Lymphoma treatment may be associated with new-onset atrial fibrillation (AF), especially among patients treated with Bruton tyrosine kinase inhibitors (BTKi). Objectives: The authors sought to assess the risk of new-onset AF, AF risk factors, and the impact of AF on mortality in patients with lymphoma and no history of AF. Methods: The University of Rochester Medical Center Lymphoma Database was used to identify patients. The primary outcome was any AF episode identified using the International Classification of Diseases-10th Revision codes. Multivariable Cox regression was used to assess the risk of AF through the use of a time-dependent covariate for treatment overall as well as separate time-varying measures of BTKi (mainly ibrutinib) and non-BTKi treatment. The relative risk of all-cause mortality was determined using Cox proportional hazards analysis. Results: Among 1,957 lymphoma patients, the rate of AF at 5-years following initiation of BTKi treatment was higher (25%) compared to those receiving non-BTKi therapy (8%), and those receiving no treatment (4%). Multivariable analysis showed that BTKi treatment was associated with pronounced increased risk for AF compared to no treatment (HR: 5.07 [95% CI: 2.88-8.90; P < 0.001]). Non-BTKi treatment was associated with an increased risk of AF compared to no treatment (HR: 1.82 [95% CI: 1.14-2.89; P = 0.012]). Risk factors for the development of AF included age ≥64 years, male sex, hypertension, and lymphoma treatment. New AF was associated with an increased risk for subsequent mortality (HR: 3.71 [95% CI: 2.59-5.31]). Conclusions: Patients undergoing lymphoma treatment, especially those with high-risk features, may benefit from AF surveillance.

Age and the Risk of Ventricular Tachyarrhythmia in Patients With an Implantable Cardioverter-Defibrillator.

BACKGROUND: The benefit of implantable cardioverter-defibrillators (ICDs) in elderly patients is controversial. OBJECTIVES: The aims of this study were to evaluate the risk for ventricular tachyarrhythmia (VTA) and ICD shocks by age groups and to assess the competing risk for VTA and death without prior VTA. METHODS: The study included 5,170 primary prevention ICD recipients enrolled in 5 landmark ICD trials (MADIT [Multicenter Automatic Defibrillator Implantation Trial] II, MADIT-Risk, MADIT-CRT [MADIT Cardiac Resynchronization Therapy], MADIT-RIT [MADIT Reduce Inappropriate Therapy], and RAID [Ranolazine in High-Risk Patients With Implanted Cardioverter-Defibrillator]). Fine and Gray regression analysis was used to evaluate the risk for fast VTA (ventricular tachycardia ≥200 beats/min or ventricular fibrillation) vs death without prior fast VTA in 3 prespecified age groups: <65, 65 to <75, and ≥75 years. RESULTS: The cumulative incidence of fast VTA at 3 years was similar for patients <65 years of age and those 65 to <75 years of age (17% vs 15%) and was lowest among patients ≥75 years of age (10%) (P < 0.001). Multivariate Fine and Gray analysis showed a 40% lower risk for fast VTA in patients ≥75 years of age (HR: 0.60; 95% CI: 0.46-0.78; P < 0.001) compared with patients <65 years of age. In patients ≥75 years of age, a risk reversal was observed whereby the risk for death without prior fast VTA exceeded the risk for developing fast VTA. A history of nonsustained ventricular tachycardia, male sex, and the presence of nonischemic cardiomyopathy were identified as predictors of fast VTA in patients ≥75 years of age. CONCLUSIONS: Patients ≥75 years of age have a significantly lower risk for VTA and ICD shocks compared with younger patients. Aging is associated with a higher risk for death compared with the risk for fast VTA, the reverse of what is seen in younger patients.

Prognostic Significance of Newly Diagnosed Atrial Fibrillation After Acute Myocardial Infarction: A Study of 184,980 Medicare Patients.

We aimed to determine whether newly diagnosed atrial fibrillation (AF) predicted cardiovascular events and death after myocardial infarction (AMI) in a large nationwide cohort of patients. All Medicare beneficiaries aged >65 years who were discharged alive after a diagnosis of AMI between January 1, 2007 and December 31, 2008 were identified. Main exposure was a diagnosis of AF during admission or within 90 days after discharge. Primary outcome was a composite of recurrent AMI, stroke and all-cause mortality. Secondary outcomes were each of recurrent AMI, stroke and all-cause mortality. We used Cox proportional hazards regression to assess the relationship between AF and time-to-event outcomes with follow up ending at 3 years. Of 184,980 patients, 9.1 % had AF; 40.6 % were male; 82.8 % were non-Hispanic whites. Mean age was 79.1 ± 8.1 years. Overall, 15.7 % had subsequent AMI, 5.7 % had stroke and 43.9 % died during a mean follow up of 26.4 months. AF was associated with a significantly increased risk of the primary outcome (Hazard ratio (HR) = 1.10; 95 % confidence interval (CI): 1.07-1.12). AF was also separately associated with significantly increased risk of recurrent AMI (HR = 1.09; 95 % CI: 1.04-1.14), stroke (HR = 1.29; 95 % CI: 1.21-1.37), and death (HR = 1.09; 95 % CI: 1.06-1.12). Neither age, race nor sex modified the effects of AF on primary or secondary outcomes. In conclusion, AF is a significant predictor of adverse cardiovascular outcomes and mortality after AMI. Further studies are needed to understand mechanisms by which AF alters outcomes in survivors of AMI.

Comparison of Frequency of Ventricular Tachyarrhythmia in Men-Versus-Women in Patients with Implantable Cardioverter-Defibrillator for Primary Prevention.

Current guidelines do not account for possible sex differences in the risk of ventricular tachyarrhythmia (VTA). We sought to identify specific factors associated with increased risk for VTA in women implanted with a primary prevention implantable cardioverter-defibrillator (ICD). Our study cohort consisted of 4,506 patients with an ICD or cardiac resynchronization therapy-defibrillator who were enrolled in the 4 landmark MADIT studies - MADIT-II, MADIT-RISK, MADIT-CRT and MADIT-RIT (1,075 women [24%]). Fine and Gray regression models were used to identify female-specific risk factors for the primary end point of VTA, defined as ICD-recorded, treated, or monitored, sustained ventricular tachycardia ≥170 beats per minute or ventricular fibrillation. At 3.5 years of follow-up, the cumulative incidence of VTA was significantly lower in women than men (17% vs 26%, respectively; p <0.001 for the entire follow-up). Use of amiodarone at enrollment, Black race, and history of previous myocardial infarction without previous revascularization was found to be independent risk factors of VTA in women. Of these factors, only Black race was associated with a statistically significant risk increase in men. At 3.5 years, the cumulative incidence of VTA in women with one or more of these risk factors was 27% compared with 14% in women with none of the risk factors (hazard ratio [confidence interval] = 2.08 [1.49 to 2.91]). In conclusion, our study, comprising 4 landmark ICD clinical trials, shows that sex and race have the potential to be used for improved risk stratification of patients who are candidates for primary prevention ICD.

Left Atrial Appendage Occlusion in the Management of Stroke in Patients With Atrial Fibrillation.

Atrial fibrillation (AF) is associated with a substantially higher risk of thromboembolism, particularly stroke events, resulting in significant morbidity and mortality. Oral anticoagulation (OAC), while effective in reducing embolic events in AF patients, is associated with an increased bleeding risk. Thus, not all patients with AF are candidates for OAC and some are only candidates for OAC in the short term. Of the available nonpharmacologic strategies for the management of AF, left atrial appendage occlusion (LAAO) has emerged as a potential approach for reducing the risk of systemic thromboembolism in AF patients eligible for OAC. LAAO can be achieved either surgically or percutaneously using an epicardial, endocardial, or a combined approach. Although available data are limited, currently available LAAO devices, and those being developed, have shown promise in reducing bleeding risk in AF patients because of the reduced overall need for anticoagulation, while maintaining efficacy in preventing thromboembolism. The optimal device will reduce both embolic and hemorrhagic strokes, and other bleeds, with a high implant success rate and a low complication rate. Until that time, anticoagulation remains the gold standard that these devices strive to surpass, and thus LAAO devices are currently indicated in patients with relative contraindication to OAC therapy.

Cardiac Resynchronization Therapy for Heart Failure.

Cardiac resynchronization therapy (CRT) has emerged as a valued nonpharmacologic therapy in patients with heart failure, reduced ejection fraction (EF), and ventricular dyssynchrony manifest as left bundle branch block. The mechanisms of benefit include remodeling of the left ventricle leading to decreased dimensions and increased EF, as well as a decrease in the severity of mitral regurgitation. This article reviews the rationale, effects, and indications for CRT, and discusses the patient characteristics that predict response and considerations for nonresponders.

A rare presentation of acute heart failure secondary to aggressive uterine leiomyosarcoma metastatic to the myocardium initially diagnosed as hypertrophic obstructive cardiomyopathy.

Uterine sarcoma is the cause of 3-9% of all uterine malignant neoplasms and has a 2-fold higher incidence in black women as compared to white women. Cellular atypia and abundant mitoses (≥10 per 10 high power fields) as seen in this patient are associated with an increased risk for metastases. Metastases to the heart are infrequently reported with a handful of cases in the literature. We present a case of a 51-year-old woman with aggressively metastatic uterine leiomyosarcoma causing acute heart failure 4 months after initial presentation.