**5.2 Electrocardiogram and Holter**

The electrocardiogram is abnormal in the majority of patients with symptomatic cardiac sarcoidosis, compared with patients that have a silent compromise in which the abnormality does not go above 9% [4, 18].

In the screening of asymptomatic patients with extracardiac sarcoidosis confirmed via biopsy [19], the most suggestive findings are:


**Table 1** summarizes the ECG manifestations with variable prevalence according to the course of the cardiac sarcoidosis [19].

As noted before, up to 34% of cases show malfunction in atrioventricular conduction (57% of patients being reversible in some series after immunosuppression therapy) [19]. Other alterations identified are changes in the ST T wave and rarely epsilon waves [4].

Ambulatory electrocardiographic monitoring which continues for 24–48 h (Holter) is useful for identification of arrhythmias, as well as their response to treatment [20].
