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Posts Tagged ‘LV mass’

Left ventricular hypertrophy is one of the most common clinical cardiac entity.It is recognised either by ECG or echocardiography.LVH has a unique place in cardiology as it can imply a  grossly pathological state  or  a marker of healthy heart as in physiological hypertrophy in athletes.

Logic would suggest , in this era of  stem cells and  nano medicine ,  every muscle fibre in ventricle is worth in gold !. So when the nature provides an  extra reserve of myocardium in the form of LVH one should welcome it , if otherwise not harmful.

Is LVH due to systemic hypertension benign ?

Not really, LVH has been shown to be an independent cardiac risk factor. (The famous Framingham study)Further LVH can result in diastolic dysfunction and the risk of cardiac failure increases.

But in spite of these observations, an  astute clinician with considerable experience will appreciate , patients with LVH fare better during an acute coronary syndrome !

This has been a consistent clinical observation . (Shall we call it as class C . ACC /AHA evidence ? )

Is LVH  an asset during ACS ?

  • A hypertrophied heart takes ischemic injury very easy , it doesn’t really hurt much . Another possibility is that in  LVH myocytes are relatively resistant to hypoxia .
  • Patients with LVH rarely show  significant wall motion defect following an STEMI.This is probably because the full thickness transmural necrosis is almost never possible even if extensive MI occurs.
  • This is also reflected in ECG  as these patients   rarely develop q waves in  following STEMI .
  • Persistent ST elevation and failed thrombolysis is very uncommon in pateints with LVH.
  • LVH provides  a relative immunity against development of cardiogenic shock . It requires 40% of LV mass destruction to produce cardiogenic shock.This can rarely happen in LVH. In a  long term analysis we have found none of the patient with LVH developed cardiogenic shock following STEMI.
  • LVH patients  are also protected against development of free wall rupture.

 Concluding message

“Lack of evidence  does not make a fact , a myth”

LVH , either pathological or physiological , has a hither to unreported beneficial effect .It acts as a myocardial  reserve and help limit the impact of STEMI .

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Heart is a muscular pump .But it contains more of  non muscular cells than contractile cells.

The average human heart which weighs 300 -400 grams . Contrary  to the popular perception heart is not purely a muscular organ. In fact myocytes constitutes only 30% of heart mass. Rest formed by

1.Fibroblasts

2.Endothelial cells

3.Purkinje cells

4.Interstitial cells

5.Collagen

6.Fibrous skeleton

7.Extracellualr matrix.

Why is this important to recognise ?

Cardiac failure is not synonymous with myocardial failure .

Many times cardiac failure is due to supporting structure failure like in connective tissue disorders.

Exceesive fibroblast proliferation and resulting in fibrosis of heart.

Cardiac interstitial failure is new emerging clincal entity.

In future individual cell based therapy will aim  at replacing specific cells that are defective or depleting.

 

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