Complications of cor pulmonale commonly include several conditions. The first is pulmonary encephalopathy, caused by respiratory failure leading to hypoxia and carbon dioxide retention, which can cause somnolence in patients and, in severe cases, lead to coma. The second is acid-base imbalance and electrolyte disturbances. Cor pulmonale may present with various electrolyte disturbances, such as hyponatremia and hypokalemia. The third is arrhythmias, most commonly manifesting as atrial premature beats or paroxysmal supraventricular tachycardia. The fourth complication is shock. Shock is not very common in cor pulmonale, but if it occurs, the prognosis is poor.