This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S, Subject name: Medicine
Which of the following is seen in second degree AV block- 
Select and explain. 
A. Change in morphology of ventricular complex, B. Increased atrial rate compared to ventricular rate, C. Increase in cardiac output, D. Decrease in stroke volume
A: Change in morphology of ventricular complex
Answer: A: Change in morphology of ventricular complex 
Explanation: There are two non-distinct types of second-degree AV block, called Type 1 and Type 2. In both types, a P wave is blocked from initiating a QRS complex; but, in Type 1, there are increasing delays in each cycle before the omission, whereas, in Type 2, there is no such patterns Second-degree atrioventricular (AV) block, or second-degree hea block, is a disorder characterized by disturbance, delay, or interruption of atrial impulse conduction to the ventricles through the atrioventricular node (AVN) and bundle of His. Electrocardiographically, some P waves are not followed by a QRS complex Ref Harrison 20th edition pg 1423