In this condition, anterior and rightward forces increases because of increased right Ventricular mass. Usually they are masked by left Ventricular forces unless right Ventricular Hypertrophy is significant
This results in tall R waves in anterior and right sided leads (aVR, V1 and V2) and deep S waves with abnormaly small r in left sided leads (l, aVL, V5 and V6). The frontal plane QRS axis shift to the right, sometimes markedly with the development of S waves in lead l, ll and lll ( S1 S2 S3 pattern).
Occasionally, posterior and rightward forces also increase because of posterior tilt of cardiac Apex. With less severe right Ventricular Hypertrophy especially when limited to the outflow tract of the right ventricule , ECG abnormalities may be limited to an rSr’ in V1 and persistent s waves in left precordial leads. This is typical of right Ventricular Volume Overload.
The ECG diagnosis of the right Ventricular Hypertrophy depends on finding of one or more of following:
- right axis deviation =>+90 degrees. 2. R> S in V1
- R< S in V6
- R>7 mm in V1
- qR in V1 without prior anteroseptal Myocardial infarction
- Right atrial abnormality (P- pulmonale).
Note the combination of finding (1) a tall R wave in V1 , (2) right axis deviation, (3) T wave invention in V1 through V3, (4) delayed precordial transition zone ; rS in V6, and (5) right atrial abnormality. An S1Q3 pattern is also present and can occur with acute or chronic right Ventricular overload syndromes.
. Secondary ST-T changes: downsloping ST segment and asymmetricaly inverted T wave in right precordial and inferior leads and
- S1 S2 S3 pattern ( S waves in l, ll, lll.
ECG evidence of right Ventricular Hypertrophy is of limited value in assessing the severity of pulmonary hypertension.
The presence of right atrial abnormality or S1 S2 S3 is associated with reduced survival.