This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: CHF, Angina Pectoris and Myocardial Infarction, Subject name: Pharmacology
Chronotropic effect means:- 
Select and explain. 
A. Drugs affecting the contractility of hea, B. Drugs affecting hea rate, C. Drugs affecting the myocardial blood flow, D. Drugs affecting diastolic relaxation
B: Drugs affecting hea rate
Answer: B: Drugs affecting hea rate 
Explanation: Effect Meaning Example Positive chronotropic Increase in hea rate Adrenaline Negative chronotropic Decrease in hea rate Acetylcholine Positive inotropic Increase in contractility Dobutamine Negative inotropic Decrease in contractility Verapamil Positive dromotropic Increase in AV conduction Dobutamine Negative dromotropic Decrease in AV conduction Vagal stimulation