Implantable cardioverter defibrillators (ICDs) have been used for primary and secondary prevention of sudden cardiac death (SCD) in cardiac sarcoidosis. We hoped to define the true incidence and potential predictors of atrial and ventricular arrhythmias in patients with ICDs for cardiac sarcoidosis.
After searching a single center database, 37 subjects were identified who had ICDs placed for primary or secondary prevention of SCD due to underlying cardiac sarcoidosis. Cardiac sarcoidosis was diagnosed based on the Japanese Ministry of Health and Welfare guidelines or findings consistent with the diagnosis on MRI or PET scan. The medical charts and ICD printouts were reviewed for all atrial and ventricular arrhythmic events and whether shocks were delivered. Results of electrocardiograms, echocardiograms, pulmonary function tests, MRIs, PET scans, and demographic data was obtained. A univariate analysis of this data was undertaken to determine predictors of atrial arrhythmias, ventricular arrhythmias, and appropriate ICD discharges.
After a mean of 61 months of follow up post ICD implantation, 56.8% of subjects had atrial arrhythmias and 56.8% had ventricular arrhythmias. 43.2% of subjects had appropriate ICD discharges. The prominent ventricular arrhythmia found was monomorphic ventricular tachycardia (32.4%). The most common atrial arrhythmia was atrial fibrillation (35.1%), though there was also an increased risk of other supraventricular tachycardias (21.7%). The mean ejection fraction of the cohort was 43%. Univariate analysis failed to identify predictors of arrhythmias or ICD discharges.
Our study indicates that there is a higher prevalence of atrial arrhythmias in cardiac sarcoidosis than previously reported. Nearly half of the subjects in this study required defibrillation for sustained ventricular arrhythmias. Surprisingly, severity of systolic dysfunction or disease burden quantified by PET does not predict risk of arrhythmia or ICD discharge.
Patients with cardiac sarcoidosis are extremely high risk for both atrial and ventricular arrhythmias. ICDs successfully deliver life saving therapy in high risk patients with myocardial sarcoid involvement. However, aside from electrophysiological studies, predicting those at risk remains difficult and further studies are necessary.
Tapan Godiwala, Grant monies (from industry related sources) Dr. Avi Fischer reports receiving research support from Medtronic and St. Jude Medical.; Consultant fee, speaker bureau, advisory committee, etc. Dr. Avi Fischer reports that he consulted for and received honoraria from Medtronic, Boston Scientific, St. Jude Medical and Spectranetics.; No Product/Research Disclosure Information