What is the likely cause of ventricular tachycardia in a male patient with a low serum potassium level?

Ventricular tachycardia often arises from disturbances in the heart's electrical conduction system, and a low serum potassium level can significantly impact cardiac function. Specifically, potassium plays a crucial role in regulating the resting membrane potential of cardiac myocytes. When potassium levels are low, this can lead to a more positive resting membrane potential, making it easier for the cells to reach the threshold for depolarization. As a result, this heightened excitability can precipitate abnormal electrical activity, leading to ventricular tachycardia.

In contrast, the other options do not directly link to the immediate effects of low potassium on cardiac electrophysiology. While increased myocardial oxygen demand and coronary artery disease can contribute to ischemia and potentially lead to arrhythmias, they are not direct consequences of low potassium. Similarly, ventilation-perfusion mismatch is related to respiratory function and does not have a direct impact on the electrical stability of the heart in the context of electrolyte imbalances. Thus, the disrupted resting membrane potential due to low potassium is the primary factor contributing to the development of ventricular tachycardia in this scenario.