Which electrolyte imbalance is responsible for rhythm disturbance of the heart. Answer: Pottasium electrolyte (Pottasium, with Sodium, plays a role in the transmission of impulses by nerve cells. Electrolytes, especially sodium and pottasium occur naturally in the body fluids. Heart disease and medications to treat it cab cause abnormal electrolyte concentrations in the body fluids. Physicians sometimes prescribe diet and medications to correct these disordered concentrations)