Endomyocardial biopsy in the diagnosis of cardiac sarcoidosis

We set out to assess the utility of endomyocardial biopsy (EMB) in cardiac sarcoidosis (CS). Historically, EMB sensitivity in CS is only ≤25%, but comprehensive analyses of its current diagnostic performance are not available. The data of 260 consecutive patients with CS (mean age 49 years, 60% female) meeting the Heart Rhythm Society diagnostic criteria were analysed retrospectively. Overall, 216 patients (83%) had undergone EMB, 47 with repeat procedures. EMB overall sensitivity was 38%, rising to 49% after repeat biopsies. On logistic regression analysis, positive EMB was predicted independently by presentation with ventricular tachyarrhythmia with an odds ratio (OR) of 3.8 (95% confidence interval [CI] 1.2-12.0, p = 0.021), left ventricular ejection fraction ≤45% (OR 3.7, 95% CI 1.5-9.1, p = 0.004), elevation of cardiac troponins (OR 2.7, 95% CI 1.1-6.4, p = 0.024), and presence of late gadolinium enhancement in left ventricular mid-apical septal segments on magnetic resonance imaging (OR 4.1, 95% CI 1.2-13.8, p = 0.024). EMB sensitivity, counting in repeats, was 16% in patients (n = 37) without any independent predictor versus 38%, 60%, 79%, and 88% in those with 1 (n = 76), 2 (n = 62), 3 (n = 33), and 4/4 (n = 8) predictors, respectively. The rate of serious complications was 0.7% without mortality or permanent harm. Positive EMB was not an independent predictor of prognosis. The sensitivity of EMB in CS depends on the extent, activity, and location of myocardial involvement, being the higher the more severe CS is. Its use should rely on weighing the pre-test likelihood and individual value of positive biopsy against the procedural risks.