Elsevier

Heart Rhythm

Volume 19, Issue 3, March 2022, Pages 352-360
Heart Rhythm

Clinical
Devices
Long-term monitoring of arrhythmias with cardiovascular implantable electronic devices in patients with cardiac sarcoidosis

https://doi.org/10.1016/j.hrthm.2021.11.025Get rights and content

Background

Risk stratification for sudden cardiac death (SCD) in cardiac sarcoidosis (CS) is challenging in patients without overt cardiac symptoms.

Objective

The purpose of this study was to determine the incidence of ventricular arrhythmias (VAs) and mortality after long-term monitoring with a cardiovascular implantable electronic device (CIED) in CS patients identified after systematic screening of patients with extracardiac sarcoidosis (ECS).

Methods

A retrospective study was performed in 547 predominantly Caucasian patients with ECS screened for cardiac involvement. If CS was diagnosed, risk stratification (high vs low risk) for SCD was performed by a multidisciplinary team. The primary endpoint was defined as sustained VA, appropriate implantable cardioverter-defibrillator (ICD) therapy, or cardiac death.

Results

In total, 105 patients were included (mean follow-up 33 ± 16 months). An ICD was implanted in 17 high-risk patients (16.2%), whereas 80 low-risk patients (76.1%) received an implantable loop recorder (ILR). Eight low-risk patients (7.6%) did not receive a device. The primary endpoint occurred in 4.8% (n = 5), with an overall annualized event rate of 1.7%. The annualized event rate was 9.8% in high-risk patients and 0.4% in low-risk patients. Nine low-risk patients received an ICD during follow-up, in 7 patients as a result of the ILR recordings. None of these patients required ICD therapy.

Conclusion

In CS patients without overt cardiac symptoms at initial presentation the annualized overall event rate was 1.7%; 10% in high-risk patients, but only 0.4% in low-risk patients. In low-risk patients long-term arrhythmia monitoring with an ILR enabled early detection of clinically important arrhythmias without showing impact on prognosis.

Introduction

Sarcoidosis is a multisystem disorder of unknown etiology, characterized by the presence of noncaseating granulomas. Nearly every organ system can be affected, including the heart. Cardiac involvement is associated with increased risk for ventricular arrhythmias (VAs), atrioventricular conduction block (AVB), and sudden cardiac death (SCD). Cardiac involvement in sarcoidosis is often clinically silent and therefore underrecognized. Autopsy series have suggested cardiac involvement in up to 25% of patients, whereas clinically overt cardiac involvement was seen in 5%–10% of cases.1 Because patients with cardiac sarcoidosis (CS) are at increased risk for SCD, screening for CS and subsequent risk stratification for SCD are imperative.2, 3, 4, 5 An implantable cardioverter-defibrillator (ICD) is recommended for patients with VA, third-degree AVB, or left ventricular ejection fraction (LVEF) <35%.2,6 Also, scar detected by cardiac magnetic resonance imaging (CMR) is strongly related to the occurrence of VA and SCD.7, 8, 9 However, less is known about patients with a preserved ejection fraction, a small amount of scar tissue and no or mild cardiac symptoms.2,6 Patients with extracardiac sarcoidosis (ECS) diagnosed with CS after screening for cardiac involvement often fulfill these criteria. In 2014, we routinely incorporated the use of implantable loop recorders (ILRs) in our center for continuous heart rhythm surveillance in CS patients without an ICD indication.10 This regimen facilitates early detection of VA and other arrhythmias in all CS patients with a cardiovascular electronic implantable device (CIED). In this study, we report the incidence of important arrhythmias and mortality after long-term monitoring in a large, predominantly Caucasian population of CS patients identified after systematic screening in an ECS population.

Section snippets

Study design

A retrospective single-center cohort study was performed in the St. Antonius Hospital, a Dutch, tertiary referral center for sarcoidosis. All patients with ECS who were referred to our CS multidisciplinary team (MDT) for CS diagnosis between January 2014 and January 2019 were retrospectively observed by chart review. The study was approved by the local institutional review board (R&D/Z19.004). No written informed consent was required. The research reported in this study adhered to the

Study population

In total, 114 of 547 patients (21%) were diagnosed with CS. Nine patients were lost to follow-up. Table 1 lists the baseline characteristics of 105 included patients. Complete follow-up on arrhythmias was available in 97 CIED patients. LVEF at baseline was predominantly preserved with mean LVEF of 57.6% ± 9.2%. In 2 patients, LVEF was <35%. In 91% of patients, LGE was present on CMR, and 70% showed active inflammation according to cardiac uptake on FDG-PET/CT. At the time of diagnosis, 39.0% of

Discussion

This is the first study reporting the use of CIED for long-term monitoring of arrhythmias in patients with CS diagnosed after systematic screening in an ECS population. Regular 24-hour Holter ECG might miss clinically important arrhythmias. Therefore, the use of ILR for continuous heart rhythm surveillance was incorporated in our daily practice in patients with CS considered at low risk for SCD.

In this study of CS patients without overt cardiac symptoms at initial presentation, the combination

Conclusion

Overall, the annualized event rate of VA and cardiac death in predominantly Caucasian CS patients without overt cardiac symptoms at initial presentation is 1.7%. Within the high-risk group, the annualized event rate is almost 10%. In low-risk patients, long-term arrhythmia monitoring with ILR enabled early detection of arrhythmias, without showing an impact on prognosis. Future prospective studies should focus on a risk stratification model based on predefined selection criteria, including

References (17)

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Funding Sources: The authors have no funding sources to disclose.

Disclosures: The authors have no conflicts of interest to disclose.

1

Dr Annelies Bakker and Dr Harold Mathijssen contributed equally to the manuscript.

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