This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Pharmacology
[{'content': 'All of the following are seen in digitalis toxicity except \nSelect and explain. \nA. Ventricular bigeminy, B. Paroxysmal atrial tachycardia with fast ventricular rate, C. Regularization of atrial fibrillation, D. Bidirectional ventricular tachycardia', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Digitalis has a narrow margin of safety. T Toxicity in cardiac is manifested as ventricular premature beats, pulses bigeminy, ventricular tachycardia, atrial tachycardia, atrial fibrillation, atrial flutter Most common among these is pulses bigeminy (REF. Essentials of medical pharmacology KD TRIPATHI 8th ed.)', 'role': 'assistant'}]