to dr. Tariq - sunshine2009

[ArchivalUser]

How are the sysotolic and diastolic proportion during "High" blood flow to the heart

[ArchivalUser]

Left ventricular contraction causes severe mechanical compression of intramyocardial

vessels.Therefore..very little if any blood flow occurs during systole.. but the right ventricular

contraction causes modest intramyocardial vessel compression...as a result significant flow

occurs during systole in right vent cont.when compared to left vent cont.

However the greatest flow under normal conditions is still during diastole.

Therefore the relative proportion of coronary oxygen delivery during the rest and during the

exercise times is more during diastole than systole..example in acute CHF we are giving the

digoxin to increase the contractility of the heart by keeping the heart rate same...and this

helps in increasing the blood flow to the heart by decreasing the systolic interval since the

systolic interval is narrowed we spend less time in systole and the benefit by spending the

less time in systole is ,it is during systole that the 02 demand is highest..therfore by

spending the less time in systole we are decreasing the duration of 02 demand and this is

the benefit to the heart and if we spend less time in systole than we are leaving more time

for diastole and we already know that during diastole the coronary flow is maximal.