Sarcoid involvement of the heart occurs in a focal manner, not in a diffuse manner as in viral myocarditis.

  Focal granulomas destruct the myocardial tissue.

  Cardiac sarcoidosis generally involves
myocardium and the conduction system of the heart

      which explains the abnormal ECG findings.

  Sarcoidosis has no diagnostic ECG finding.

  The presence of a normal ECG is not enough to exclude the diagnosis of cardiac sarcoidosis.

ECG abnormalities that may be observed in cardiac sarcoidosis

  Atrioventricular (AV) blocks

  Bundle branch blocks

  Ventricular arrhythmias: frequent VPCs, attacks of ventricular tachycardia

  Abnormal (pathological) Q waves

References and links to sample ECGs

  Circulation 2009;120:1550-1551.

  Tex Heart Inst J 2009;36:501-503.

  Tex Heart Inst J 2011;38:74-76.

  Circulation 2008;118:e113-e115.

  Europace 2010;12:284-288.

  Europace 2008;10:760-766.

  Europace 2007;9:134-136.

  Heart 2005;91:1388.

  J Interv Card Electrophysiol 2009;26:181-184.

  Ann Noninvasive Electrocardiol 2009;14:319-26.

  Semin Respir Crit Care Med 2010;31:428-441.