Cardiac Sarcoidosis, Left Ventricular Impairment and Chronic Right Ventricular Pacing: Pacing or Pathology?

Cardiac sarcoidosis preceded by sick sinus syndrome presenting as biventricular involvement and intracardiac giant thrombus: a case report

Background

Sarcoidosis is a granulomatous disorder characterized by the formation of non-necrotizing granulomas in various organs. Cardiac sarcoidosis presents with various clinical, anatomical, and electrophysiological manifestations. As cardiac involvement is related to adverse outcomes, the early diagnosis of cardiac sarcoidosis is crucial and sometimes challenging.

Case summary

A 65-year-old woman was initially treated for sick sinus syndrome (SSS) with normal cardiac function. Cardiac conduction defects and biventricular dysfunction continued to progress over a short clinical course, and the patient was eventually referred to our hospital for further investigation and treatment of cardiogenic shock due to pacemaker pacing failure. An echocardiography revealed a large thrombus formation in the right ventricle and atrium. An urgent thrombectomy was performed, and myocardial biopsy confirmed the diagnosis of cardiac sarcoidosis. Steroid pulse therapy was initiated and was effective in treating the cardiogenic shock. One year after discharge, the patient manifested with sustained ventricular tachycardia and ultimately died of severe cardiac pump failure. On autopsy, diffuse fibrotic tissues were noted in both ventricles and atria.

Discussion

While conduction abnormalities, such as right bundle brunch block and atrioventricular block, are common clinical manifestations, SSS is rarely reported as a primary manifestation of cardiac sarcoidosis. Thus, clinicians should ensure that sufficient investigations are carried out when diagnosing idiopathic SSS.

Outcomes after transvenous defibrillator implantation in cardiac sarcoidosis: A systematic review

Introduction

Sarcoidosis is a systemic inflammatory disorder associated with ventricular arrhythmias (VAs) and sudden death in the context of cardiac involvement. Guidelines advocate implantable cardioverter‐defibrillator (ICD) implantation in specific subcohorts, but there is a paucity of data on outcomes.

Methods and Results

A systematic review was performed to assess outcomes in patients with definite or probable cardiac sarcoidosis (CS) treated with ICD. Observational studies were identified from multiple databases from inception to 21st May 2021. Outcomes of interest included appropriate and inappropriate ICD therapies in addition to all‐cause mortality. Study quality was assessed individually using the Newcastle Ottawa Scale (NOS).

Eight studies were identified comprising 530 patients, with follow‐up period of 24–66 months (weighted average 40 months). Mean age was 53.9 years with ejection fraction of 41.3%. Overall incidence of appropriate therapy was 38.1% during follow‐up. Left ventricular systolic dysfunction (LVSD) with ejection fraction <40% was a predictor of appropriate therapy in the majority of studies, as were sustained VAs during electrophysiological testing (EP) in one study. There was no interaction with device indication (i.e. primary or secondary). Where documented, inappropriate therapy was primarily driven by atrial arrhythmias. All‐cause mortality was 6.0% over a median follow‐up period of 42 months. Only three studies achieved good quality in the comparability domain of NOS.

Conclusions

Appropriate ICD therapy in patients with CS is commonly associated with LVSD, which can act as a surrogate for scar burden. The utility of EP testing in this setting remains unclear.

Severe left ventricular systolic dysfunction after permanent pacemaker implantation: Should we pause before upgrading to biventricular pacing?

Left ventricular (LV) systolic dysfunction leading to heart failure (HF) is known to occur after permanent pacemaker implantation (PPI) in a subset of patients. They are often treated by upgradation of the pacemaker to cardiac resynchronisation therapy (CRT). We report a case of progressive LV dysfunction and HF after PPI. Cardiac ¹⁸FDG-PET-CT scan revealed abnormal myocardial FDG uptake suggestive of cardiac sarcoidosis (CS). Biopsy from FDG avid lymph node demonstrated non-caseating granuloma. Therapy with steroids resulted in resolution of HF symptoms accompanied by a significant improvement in LV function.

The Prevalence of Pacing-Induced Cardiomyopathy (PICM) in Patients With Long Term Right Ventricular Pacing - Is it a Matter Of Definition?

BACKGROUND

Chronic right ventricular pacing may contribute to deterioration in left ventricular ejection fraction (LVEF). The aim of the study was to identify the prevalence of pacing-induced cardiomyopathy (PICM) in patients with chronic right ventricular pacing.

METHODS

Patients attending a pacemaker clinic were retrospectively identified as having had transthoracic echocardiographic LVEF measurement during the 12 months prior to device implantation. Those with cardioverter-defibrillators or biventricular devices were excluded. The remaining patients were invited back for a repeat echocardiogram. Three (3) different definitions of PICM were employed: 1) follow-up LVEF of ≤40% if baseline LVEF was ≥50%, or an absolute reduction in LVEF ≥5% if baseline LVEF was <50%; 2) follow-up LVEF of ≤40% if baseline LVEF was ≥50%, or an absolute reduction in LVEF ≥10% if baseline LVEF was ≤50%; 3) absolute reduction in LVEF ≥10% irrespective of baseline LVEF. Alternate causes of cardiomyopathy were excluded following a chart review.

RESULTS

The study cohort of 118 included 67 males (mean age 77.8±10.5years) and 51 females (mean age 76.8±11.2years). The mean time between baseline and follow-up echocardiograms was 3.5+1.4years (range 1.5-6.4 years). The prevalence of PICM ranged from 5.9 to 39.0% depending on PICM definition. Multivariate analysis found that PICM was significantly associated with ventricular pacing burden (p=0.013).

CONCLUSIONS

The prevalence of pacing induced cardiomyopathy is dependent on current accepted clinical definitions. A clear definition of PICM is required for a better understanding of the clinical implications of right ventricular pacing.