Cardiac findings may include:
(1) heart failure
(2) cardiomyopathy (hypertrophic, dilated, peripartum, other)
(3) left ventricular hypertrophy
(4) abnormal heart rate (bradycardia, high-grade heart block)
(5) cardiac arrhythmia (ventricular pre-excitation, Wolff-Parkinson-White, tachyarrhythmias)
(6) minor ECG changes
(7) sudden death
Reasons to consider mitochondrial cardiomyopathy:
(1) unexplained heart failure
(2) lactic acidosis
(3) worsening on exposure to a drug affecting respiratory chain function (valproic acid, statin, tetracycline, erythromycin, etc)
(4) inheritance from mother
(5) extra-cardiac manifestations of mitochondrial disorder
