Table 1.

Potential substrates for ventricular arrhythmias in heart failure (HF)

	Alterations
Ventricular structure and mechanics	Ventricular scar Ventricular hypertrophy High ventricular filling pressure Increases in cardiac preload and afterload
Ventricular metabolism	Acidosis and increases of lysophosphoglycerides, adenosine, lactate, and carbon dioxide in the extracellular fluid Increases of calcium, magnesium, sodium, and cyclic adenosine monophosphate in the intracellular fluid Increase or decrease of extracellular potassium levels
Ventricular electrophysiology	Prolongation of action potential duration QT prolongation and dispersion
Neurohumoral substances	Elevation of plasma epinephrine and norepinephrine Cardiac sympathetic overactivation