Greetings.
Your father must have been give drugs which are called as calcium channel blockers. They have various indication for multiple heart and vascular disorders.
There are conditions called as arrhythmias. Read about them here.
The top part of the heart is composed of atriums while lower portion is made of ventricles. The heart rhythm travels from atrium to ventricles. In some arrhythmia disorders, these rhythm may not travel properly and atriums and ventricles may not work or contract in synchronization. I think your father's physician wanted to explain this thing to you.
Hope this helps. Please feel free, if you have further questions.
Dr. Arun
Edited by Dr. Arun Phophalia on December 12 2007 at 11:16 PM
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