Cardiac carnitine leakage is promoted by cardiomyopathy
Recall that carnitine is used to shunt fatty acids into the mitochondria so the mitochondria can burn the fatty acids for energy formation. It also functions in the reverse to remove toxins form the mitochondria. So, lowering carnitine==potential for less energy production and mitochondrial dysfunction. This effect would be larger in higher respiratory tissues like heart, brain, liver and skeletal muscle.
This particular study sees a link with cardiomyopathy.