Pacemaker current is strangely referred by physiologists as funny current (I f ) . I am yet to find the exact reason . This is the current that sustain our life right from the day 22 of embryonic life when the cardiac jelly beats for the first time. SA node solemnly follow our entire life before making a bid-adieu !
What is contribution of If current in the overall Pace-making activity ?
This has not been quantified . The fact that , Ivabradine induced If current blockade does not result in serious bradycardia indicate , SA node has alternate reserve currents as well . ( SA node is a such a mystery structure , it would never be a surprise , if we find many more “not so funny” currents !)
Dr.S.Venkatesan MD 
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