Hypertension is the most common clinical cardiovascular entity.Left ventricular hypertrophy (LVH) is an important consequence of HT.In fact, it is considered as a end organ effect or damage. Others being brain, kidney, and peripheral vascular disease.Knowing about LVH is important because it has been linked to increased cardiovascular events.
Though LVH is considered as a close companion of HT it is surprising only a minority (15-30%) show evidence of LVH .Some experienced clinicians (Level C evidence) quote even lower < 10 % .Traditionally LVH was detected by ECG and now it is replaced by echocardiography.
What determines the LVH ?
It will be suprising to note , answer to this question is still not clear .
- Is it the duration of elevated blood pressure ?
- Is it the absolute level of blood pressure ?
- If so , is it the systolic BP , diastolic BP or the mean BP ?
- Or is it related to the etiology of HT ?
- There has been no significant correlation between the above parameters
When we don’t know the answer to a question in medicine , the answer will generally will be inside the genes !
So in HT also the major determinant of LVH is in the genes that determine the myosin heavy chain response .
and also ACE gene polymorphism.ACE genes are involved in the expression of growth factors within the myocardium.
An excellent study on the issue http://www.nature.com/jhh/journal/v17/n3/full/1001523a.html#tbl1
It implicates , gender, age, race etc in the genesis of LVH
Final message
So , the myocardium does not respond with LVH in all patients with HT.It happens only in a minority* .Duration of HT can be an important determinant , but the major factor is the alteration of genetic switches within the myocytes How this switches are going to behave , is largely inherited .Regression of LVH is also not uniform again implying lesser role for hemodynamics. (Some studies revealed ACEI have maximum regression of LVH , later disputed )
*LVH is more consistently seen in hypertension due to reno vascular or parenchymal disorders .It is also an observed fact , a combination of diabetes and HT is more likely to result in LVH.
The other major issue that needs explanation in HT/LVH is , how much of LVH is due to myocyte hypertrophy perse and how much is contributed by interstitial cell hypertrophy(Non myocytic hypertrophy)
This issue will be discussed soon
A normally functioning circulatory system is vital for our survival . We have about 6000 ml of blood, circulating all over the body in an approximate time of 15-20 seconds.The pressure at which this blood moves across the body is called the blood pressure . Hypertension or simply , high blood pressure is an undesirable hemodynamic disturbance in human circulatory system.Systemic hypertension is the most common type of hypertension. The blood pressure is primarily dependent on the status of the blood vessel(vascular resistance) and cardiac contractility. This regulation is under many neural and hormonal factors.Further the blood pressure varies depending upon the blood vessel calibre, and the local milieu.There is a progressive drop in blood pressure from major arteries to the small arteries .The pressure drop is maximum across the arterioles to reach the venules .The venous circulation has the lowest pressure, it ends up at right atrium with a mean pressure of 0- 5mmhg.
Dr.S.Venkatesan MD 
