# Prevalence of ventricular parasystole in patients with cardiac sarcoidosis: correlation between parasystole and inflammation in ventricular fibrillation

## TL;DR

This study found that ventricular parasystole is common in patients with cardiac sarcoidosis and is linked to ventricular fibrillation and inflammation.

## Contribution

The study is the first to correlate ventricular parasystole with inflammation in cardiac sarcoidosis patients.

## Key findings

- Ventricular parasystole was observed in 33.7% of patients with cardiac sarcoidosis.
- Parasystole was significantly more common in patients who developed ventricular fibrillation.
- Inflammation sites matched the origin of parasystole in patients with ventricular fibrillation.

## Abstract

Ventricular parasystole is strongly associated with ventricular fibrillation (VF) in patients with non-ischaemic cardiomyopathy. However, the relationship between ventricular parasystole and cardiac sarcoidosis (CS) remains unclear. The purpose of this study was to examine the prevalence of parasystole in patients with CS.

This was a retrospective observational study of 214 consecutive patients diagnosed with CS (mean age: 69±12 years, 104 males, median follow-up period: 6.8 years (IQR: 3.2–10.7) in our centre. We investigated parasystole in the patients who developed ventricular arrhythmia (VA) using 9886 ECGs, 280 Holter ECGs and 6391 implantable cardioverter defibrillator interrogation records. Classic parasystole was defined as three ventricular ectopic beats with the same morphology, occurring at integer-multiple intervals but with different coupling intervals (CI) on ECG. New parasystole was defined as two ventricular ectopic beats with a CI difference of more than 120 ms. We also analysed the correlation between inflammation sites and parasystole morphology observed on a 12-lead ECG.

VA was identified in 95 patients (33.7%), and 22 developed VF (23.2%). Parasystole was observed in 12 of the 22 patients with VF (classic: 5, new: 7), 20 of 73 with ventricular tachycardia (classic: 5, new: 15) and 44 of 118 without VA (classic: 16, new: 28). Parasystole was significantly more common in the VF group than in the non-VF group (p=0.049). The site of inflammation observed on 18F-fluorodeoxyglucose positron emission tomography performed within 3 months after the development of VA and the origin of parasystole matched in all four patients with VF who had 12-lead ECG records of parasystole. Inflammation was correlated with the origin of parasystole.

Ventricular parasystole was detected in one-third of patients with CS in this study, especially those with VF. The presence of parasystole and inflammation may predict the occurrence of VF in patients with CS.