Background-This study was designed to assess the epidemiology, characteristics, and outcome of cardiac sarcoidosis (CS) in Finland. Methods and Results-We identified in retrospect all adult (>18 years of age) patients diagnosed with histologically confirmed CS in Finland between 1988 and 2012. A total of 110 patients (71 women) 51±9 years of age (mean±SD) were found and followed up for outcome events to the end of 2013. The annual detection rate of CS increased >20-fold during the 25-year period, reaching 0.31 in 1×10 5 adults between 2008 and 2012. The 2012 prevalence of CS was 2.2 in 1×10 5 . Nearly two thirds of patients had clinically isolated CS. Altogether, 102 of the 110 patients received immunosuppressive therapy, and 56 received an intracardiac defibrillator. Left ventricular function was impaired (ejection fraction <50%) in 65 patients (59%) at diagnosis and showed no overall change over 12 months of steroid therapy. During follow-up (median, 6.6 years), 10 patients died of a cardiac cause, 11 patients underwent transplantation, and another 11 patients suffered an aborted sudden cardiac death. The Kaplan-Meier estimates for 1-, 5-, and 10-year transplantation-free cardiac survival were 97%, 90%, and 83%, respectively. Heart failure at presentation predicted poor outcome (log-rank P=0.0001) with a 10-year transplantation-free cardiac survival of only 53%. Conclusions-The detection rate of CS has increased markedly in Finland over the last 25 years. With current therapy, the prognosis of CS appears better than generally considered, but patients presenting with heart failure still have poor longterm outcome. (Circulation. 2015;131:624-632.

Aims The present study was done to assess the role of sudden cardiac death (SCD) among the presenting manifestations of and fatalities from cardiac sarcoidosis (CS). Methods and results We analysed altogether 351 cases of CS presenting from year 1998 through 2015 in Finland. There were 262 patients with a clinical diagnosis and treatment of CS, 27 patients with an initial lifetime diagnosis of giant cell myocarditis that was later converted to CS, and 62 cases detected at autopsy and identified by screening >820 000 death certificates from the national cause-of-death registry. The total case series comprised 253 females and 98 males aged on average 52 years at presentation. High-grade atrioventricular block was the most common first sign of CS (n = 147, 42%) followed by heart failure (n = 58, 17%), unexpected fatal (n = 38) or aborted (n = 12) SCD (14%), and sustained ventricular tachycardia (n = 48, 14%). Severe coronary artery disease was found at autopsy concomitant with CS in four of the 38 cases presenting with fatal SCD. Of all deaths recorded till the end of 2015, 64% (n = 54/84) were unexpected SCDs from CS that had either been silent during life or defied all attempts at diagnosis. The Kaplan–Meier estimate (95% CI) of survival from symptom onset was 85% (80–90%) at 5 years and 76% (68–84%) at 10 years. Conclusion Together fatal and aborted SCD constitute 14% of the presenting manifestations of CS. Nearly two-thirds of all fatalities from CS are caused by undiagnosed granulomas in the heart.