The left atrium always dilate to pressure overload.And it almost never hypertophies even whne the mean LA pressure raises to high levels. Why ?
1.The atrium basically has little muscle cells to hypertrophy.The left atrial thickness is only 2mm.
They are basically designed to passively fill the ventricles. But this is not always true physiologically.We
call it as booster pump and 30% of LV filling is contributed by active pumping of left atrium.
2. The second reason for left atium not gettting hypertrophied is , there are four decompressing exits
(safety valves) in left atrium namely, pulmonary viens. In fact it’s a paradox the back pressure across
pulmonary circulationmay result in RV hypertrophy
Inference & potential research areas
If by some mechanism if we can induce hypertophy of left atrium will it be a mechanical advantage for left ventricle in failing hearts .By cell therapy we can convert inert atrial cells into activley contracting cells.
DR.S.Venkatesan, madras medical college, Chennai, India .
Dr.S.Venkatesan MD 