Question

How can we differentiate left ventricular hypertrophy due to a physiological adaptation (exercise training) from that due to a pathological adaptation (chronic hypertension)? Why does the atria and right ventricle remain unchanged?

Answer 1

Left ventricular hypertrophy physiological also called athletic heart if diagnosed as pathological can be devastating for the patient.so we diagnose it in multiple modalities

1)History and clinical examination-athletic heart is seen in athletes involved in both isotonic and isometric exercises

2)ECG and Exercise testing-Presence of changes such as T wave inversions,pathological Q wave and ST depression is concerned with pathological cardiac hypertrophy.Cardiopulmonary exercise testing is very usuefull in differentiationg.

3)Imaging-Echocardiography is the mainstay of imaging for evaluation .LVH occurs at the cost of left ventricular cavity size(<45 mm).It is the most important descriminator between physiological LVH and HCM(hypertrophic cadrdiomyopathy).Cardia magnetic resonance(CMR) evaluates both right and left ventricle,coronary artery,valve disease,aortic disease

4)Endomyocardial biopsies have no role,however presence myocradial fiber disarray on biopsy is diagnostic of HCM.

5)Detraining

Findings suggestive of pathological LVH

-Pathological Q wave

-Peak VO2 max <50ml/kg/min

-LVH greater than 16 mm

-Small left ventricular cavity diameter(<45mm)

-Presence of late Gd enhancement by CMR

Left ventricles are affected because the left ventricle is the pumping chamber and is the one on the end where there is the factor of peripheral resistance comes to play and is under constant pumping activity ,it can lead to hypertrophy and not other chambers.