In hypertrophy the heart muscle becomes thicker. This can have different causes. Left ventricular hypertrophy results from an increase in left ventricular workload, e.g. during hypertension or aortic valve stenosis. Right ventricular hypertrophy results from an increase in right ventricular workload, e.g. emphysema or pulmonary embolization.
These causes are fundamentally different from [[Miscellaneous#Hypertrophic_Obstructive_Cardiomyopathy|hypertrophic obstructive cardiomyopathy (HCM)]], which is a congenital misalignment of cardiomyocytes resulting in hypertrophy.
;Criteria for left atrial voor left atrial enlargement. Either
:P wave with a broad (>0
,04 sec or 1 small square) and deeply negative (>1 mm) terminal part in V1:P wave duration >0 ,12 sec in leads I and / or II
Left atrial enlargement is often seen in mitral valve insufficiency, resulting in back flow of blood from the left ventricle to the left atrium and subsequent increased local pressure.