Overlooked and Underdiagnosed: Cardiac Sarcoidosis and Unexplained Ventricular Tachycardia and Fibrillation

Cardiac sarcoidosis (CS) often manifests as unexplained ventricular tachycardia (VT) and ventricular fibrillation (VF) but remains significantly underdiagnosed. Although guidelines recommend advanced diagnostics, many clinicians may not pursue this in patients presenting with unexplained VT/VF.

The objective of the study was to assess the proportion of patients with unexplained VT/VF who underwent guideline-based evaluation for CS.

Using TriNetX data, we conducted a retrospective cohort study of patients aged 18 years or older who presented with unexplained VT/VF requiring implantable cardioverter defibrillator device implantation over the past 5 years. We evaluated the use of cardiac diagnostic modalities; including cardiac magnetic resonance imaging, positron emission tomography imaging, chest computed tomography, and myocardial biopsy, and monitored subsequent diagnoses of CS over a 5-year follow-up period.

Of 732 patients with VT/VF across 56 healthcare organizations, the mean age was 53 ± 19 years. Of these, 61% were male and 73% were White, while 8% were African American. The mean follow-up duration was 827 days (interquartile range: 0-1,1167). Cardiac magnetic resonance imaging was performed in 146 patients (19.9%; 95% CI: 17.21%-22.99%), cardiac positron emission tomography in 17 patients (2.3%; 95% CI: 1.45%-3.69%), chest computed tomography in 54 patents (7.4%; 95% CI: 5.70%-9.50%), and myocardial biopsy in < 10 patients (1.4%; 95% CI: 0.74%-2.50%). Sarcoidosis was diagnosed in <10 patients (1.4%; 95% CI: 0.74%-2.50%).

Despite established guidelines, testing for CS remains underutilized in patients with unexplained VT/VF. This diagnostic gap contributes significantly to the lower prevalence of CS (1.4%) than the expected 17% to 28% in this cohort and suggests an area for improvement.