Matthew M. Zipse

Implantable Cardioverter Defibrillator Therapy in Patients with Cardiac Sarcoidosis

ICD Shocks in Cardiac Sarcoidosis. Background: An implantable cardioverter defibrillator (ICD) is indicated for some patients with cardiac sarcoidosis (CS) for prevention of sudden death. However, there are little data regarding the event rates of ICD therapies in these patients. We sought to identify the incidence and characteristics of ICD therapies in this patient population.

Electrocardiographic Characteristics in Patients With Pulmonary Sarcoidosis Indicating Cardiac Involvement

ECG Characteristics of Cardiac Sarcoidosis. Introduction: Sarcoidosis is a multisystem granulomatous disease that can affect the heart. Early identification of cardiac sarcoidosis (CS) is critical because sudden death can be the initial presentation. We sought to evaluate the potential role of the ECG for identification of cardiac involvement in a cohort of patients with biopsy‐proven pulmonary sarcoidosis.

Safety of Ventricular Tachycardia Ablation in Clinical Practice

Background—Outcomes of ventricular tachycardia (VT) ablation have been described in clinical trials and single-center studies. We assessed the safety of VT ablation in clinical practice. Methods and Results—Using administrative hospitalization data between 1994 and 2011, we identified hospitalizations with primary diagnosis of VT (International Classification of Diseases-9 Clinical Modification code: 427.1) and cardiac ablation (International Classification of Diseases-9 Clinical Modification code: 37.34). We quantified in-hospital adverse events (AEs), including death, stroke, intracerebral hemorrhage, pericardial complications, hematoma or hemorrhage, blood transfusion, or cardiogenic shock. Secondary outcomes included major AEs (stroke, tamponade, or death) and death. Multivariable mixed effects models identified patient and hospital characteristics associated with AEs. Of 9699 hospitalizations with VT ablations (age, 56.5±17.6; 60.1% men), AEs were reported in 825 (8.5%), major AEs in 295 (3.0%), and death in 110 (1.1%). Heart failure had the strongest association with death (odds ratio, 5.52; 95% confidence interval, 2.97–10.3) and major AE (odds ratio, 2.99; 95% confidence interval, 2.15–4.16). Anemia (odds ratio, 4.84; 95% confidence interval, 3.79–6.19) and unscheduled admission (odds ratio, 1.64; 95% confidence interval, 1.37–1.97) were associated with AEs. During the study period, incidence of AEs increased from 9.2% to 12.8% as did the burden of AE risk factors (0.034 patient/y; P<0.001). Hospital volume >25 cases/y was associated with fewer AEs compared with lower volume centers (6.4% versus 8.8%; P=0.008). Conclusions—VT ablation–associated AE rates in clinical practice are similar to those reported in the literature. Over time rates have increased as have the number of AE risk factors per patient. Ablations done electively and at hospitals with higher procedural volume are associated with lower incidence of AEs.

Diagnostic Utility of Signal‐Averaged Electrocardiography for Detection of Cardiac Sarcoidosis

Introduction: Cardiac sarcoidosis (CS) occurs in up to 25% of patients with pulmonary involvement. Early diagnosis is critical because sudden death from ventricular arrhythmias can be the initial presentation. We sought to evaluate the diagnostic utility of signal‐averaged ECG (SAECG) for detection of cardiac involvement of sarcoidosis.

Electrophysiologic manifestations of cardiac sarcoidosis.

Purpose of review Cardiac involvement in sarcoidosis patients is frequently unrecognized with ventricular arrhythmias and sudden cardiac death (SCD) sometimes occurring as its initial presentation. Early involvement of an electrophysiologist as part of a multidisciplinary team is essential to screening, risk stratification, and management of cardiac sarcoidosis patients. This review outlines potential manifestations of cardiac sarcoidosis, as well as diagnostic and treatment strategies. Recent findings Recent retrospective analyses have shown that the incidence of atrioventricular block, atrial tachyarrhythmias, and ventricular tachyarrhythmias in these patients is substantial. In addition to advanced cardiac imaging, there is a role for ECG, signal-averaged ECG, ambulatory telemetry monitoring, and electrophysiologic testing in the initial evaluation of a patient with suspected cardiac sarcoidosis. There have been recent investigations into the role of implantable cardioverter-defibrillators (ICDs) for SCD prevention with a high rate of appropriate therapies observed. Immunosuppressive therapy, antiarrhythmic drugs, and catheter ablation each also have a role in the reduction of overall arrhythmic burden. Summary The electrophysiologists approach to a patient with cardiac sarcoidosis can aid in diagnosis, risk stratification, and management with antiarrhythmic therapy, catheter ablation, and ICD implantation for the prevention of SCD.

Clinical and biophysical evaluation of variable bipolar configurations during radiofrequency ablation for treatment of ventricular arrhythmias

BACKGROUND Bipolar radiofrequency ablation (bRFA) has been used to create larger ablation lesions and to treat refractory arrhythmias. However, little is known about optimal bRFA settings. OBJECTIVE The purpose of this study was to evaluate various bRFA settings, including active and ground catheter tip orientation and use of variable active and ground catheters during bRFA. METHODS Two ablation catheters, 1 active and 1 ground, were oriented across from each other, with viable bovine myocardium in between. The catheter tips were placed in various combinations perpendicular or parallel to the myocardium. The active catheter was either a 3.5-mm externally irrigated or 8-mm tip, and the ground catheter was either a 4-mm, 3.5-mm irrigated, or 8-mm tip. Retrospective analysis was undertaken for all bRFA performed at University of Colorado. RESULTS The largest and deepest lesions were produced using irrigated active and ground tips, oriented perpendicularly. In 14 cases (10 patients) of bRFA for ventricular tachycardia and premature ventricular complexes, acute success was achieved in 13 of 14 procedures. Long-term success was achieved in 7 of 10 patients, but 3 patients required multiple bRFA ablations. CONCLUSION Active and ground catheter tip orientation and type are important determinants of lesion sizes during bRFA. The largest and deepest lesions, without a higher incidence of steam pops, were achieved using 2 irrigated catheters. As the largest published series to date, bRFA ablation can be performed safely and effectively in humans. Larger studies are necessary to better evaluate bRFA efficacy and safety.

Inappropriate Shocks due to Subcutaneous Air in a Patient With a Subcutaneous Cardiac Defibrillator

A 56-year-old man with a history of ischemic cardiomyopathy and a transvenous implanted cardiac defibrillator (ICD) for secondary prevention presented with device endocarditis requiring ICD removal and lead extraction. After extended therapy with intravenous antibiotics and resolution of systemic infection, a subcutaneous implantable cardiac defibrillator (S-ICD; Cameron Health/Boston Scientific, San Clemente, CA) was electively implanted with standard technique.1 Specifically, 3 subcutaneous pockets were created, a subaxillary pocket for the generator and 2 parasternal pockets, to which the defibrillator coil was tunneled. After the coil and generator were positioned and sutured and after the fascial layer was closed, sustained ventricular fibrillation was induced. Detection was successful in the primary vector, which involves the pulse generator and proximal parasternal sensing electrode (Figure 1). Sinus rhythm was effectively restored with a submaximal 65-J polarity shock with time to therapy of 13 seconds and impedance of 55 Ω. Device interrogation the next day was unremarkable; the device, per its automatic programming, chose the secondary vector for detection (which involves the pulse generator and distal parasternal sensing electrode; Figure 1). The postoperative course was otherwise uneventful, and the patient was discharged the following day. Figure 1. Anteroposterior chest film after device implantation, with notations illustrating possible sensing vectors that can be programmed with the subcutaneous implantable …

Incidence and Predictors of Late Complete Heart Block After Alcohol Septal Ablation Treatment of Hypertrophic Obstructive Cardiomyopathy

OBJECTIVES This study was designed to identify the incidence of late complete heart block (CHB) first identified at least 48 hours post alcohol septal ablation (ASA). BACKGROUND Septal reduction with ASA is a therapeutic option for patients with symptomatic hypertrophic obstructive cardiomyopathy (HCM). CHB, resulting from the septal infarct, is a known complication with a reported incidence of 9-22%. The incidence of CHB more than 48 hours post-procedure is unknown. METHODS Consecutive patients who underwent ASA were analyzed and clinical characteristics associated with late CHB were assessed. Late CHB was defined as first identification of CHB more than 48 hours after ASA. RESULTS From 2002-2013, 145 subjects underwent 168 ASA procedures and were followed for a mean of 3.2 +/- 2.3 years. The incidence of late CHB was 8.9% (15/168 ASA procedures). Heart block occurred from 48 hours to 3-years post-procedure. In a multivariable model, patients with any CHB were more likely to have had multiple ASA procedures (OR 4.14; 95% CI: 1.24, 13.9; P < 0.05) and high resting and provoked left ventricular outflow tract (LVOT) gradient assessed by catheterization (OR per 10 mmHg gradient 1.14; 95% CI: 1.0, 1.20; P < 0.05). After multivariable adjustment, only a high provokable LVOT gradient remained an independent predictor of late CHB (OR per 10 mmHg gradient 1.14 [95% CI 1.02-1.29]). CONCLUSIONS Late CHB is a common complication of ASA for treatment of symptomatic HCM. Post-discharge electrocardiographic surveillance for atrioventricular conduction disease should be considered after ASA, especially for those with a high provokable LVOT gradient.

Sudden cardiac death in nonischemic cardiomyopathy: Refining risk assessment

Sudden cardiac death (SCD) risk assessment among patients with nonischemic cardiomyopathy (NICM) has been has been less straightforward than for patients with ischemic cardiomyopathy. The common surrogate that has been associated with highest SCD risk for all cardiomyopathies, and which has been universally used to guide implantation of primary‐prevention implantable cardioverter‐defibrillators (ICDs), is left ventricular ejection fraction (LVEF) ≤35%. However, this practice has been called into question, especially in light of recent trials suggesting that ICD treatment may not be of additional survival benefit among those with NICM treated with optimal medical therapy. This Clinical Review attempts to offer refinements to the current practice of SCD risk assessment among patients with NICM, with specific focus on importance of NICM etiology and efforts to identify myocardial scarring and arrhythmogenic substrate, both of which may provide greater information about SCD risk than the LVEF alone. These concepts are illustrated further as they apply to hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, and cardiac sarcoidosis, all of which are increasingly recognized NICM substrates associated with SCD and for which refinements for assessing risk are lacking in conventional guidelines.

Cardiac Sarcoidosis and Consequent Arrhythmias

Myocardial involvement in patients with sarcoidosis can be difficult to diagnose, and requires a high index of suspicion and low threshold for screening. The presentation of cardiac sarcoidosis is variable, and can range from asymptomatic electrocardiographic changes to sudden cardiac death. This review provides an overview of the arrhythmic consequences of cardiac sarcoidosis, with emphasis on the electrophysiologists role in recognition, diagnostic testing, and management of this rare disease.