Right and Left Ventricular Hypertrophy

Look for signs of right and left ventricular hypertrophy in the right chest leads (V1 and V2) and left chest leads (V5 and V6).

When the ventricles are normal, the QRS complexes across the chest leads of an ECG have these configurations:

Back to contents In right chest leads V1 and V2, the QRS complexes are predominantly negative with small R waves and relatively deep S waves because the more muscular left ventricle produces depolarization current flowing away from these leads.
Back to contents In left chest leads V5 and V6, the QRS complexes are predominantly positive with tall R waves because the more muscular left ventricle produces net current flowing towards these leads.
Back to contents The QRS complexes in V3 and V4 reflect a transition between the right and left chest leads. The normal transition zone, where the R wave and S wave are equal, is between V3 and V4. Early transition may appear in V2 while late transition may not appear until V5 or V6.

In right ventricular hypertrophy (RVH), the configurations of the QRS complexes across the chest leads are changed:

Back to contents In V1 the QRS are positive with tall R waves. This is because increased right ventricular muscle mass causes the net ventricular depolarization current to move towards this right chest lead. R wavesthat are taller than S waves are deep in V1 are highly suggestive of RVH.
Back to contents The S waves are unusually deep in V6 and may be even deeper than the R wave is tall.

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Other ECG signs of RVH include:

    Back to contents Right axis deviation due to the overpowering current generated by a hypertrophied right ventricle.
    Back to contents Ventricular repolarization changes manifest as downward sloping of the ST segment and T wave inversion, the so called ventricular strain pattern, may or may not be present in the right chest leads. (See V1 in above ECG.)
    Back to contents P wave > 2.5 mm tall in lead II, III, aVF or biphasic P wave in V1 suggesting the presence of right atrial enlargement. (Right atrial abnormality results from the right atrium having to pump blood into a thick-wall non-compliant hypertrophied right ventricle.)

In left ventricular hypertrophy (LVH), the configurations of the QRS complexes across the chest leads are also changed and consist of:

Back to contents Unusually tall R wave in left chest leads V5 and V6 and unusually prominent S wave in right chest leads V1 and V2. These are exaggerations of the normal configurations due to increase in left ventricular muscle mass.
Back to contents The sum of the S wave in V1 and the R wave in V5 or V6 is > 35 mm. (Tall R waves in chest leads is common among young and slender individuals. This finding alone should not be used as the only criteria of LVH.)

 

Additional ECG signs of LVH include:

    Back to contents R waves taller than 14 mm in lead I or taller than 11 mm in Lead aVL. However, tall R waves in limb leads and chest leads do not always coexist.
    Back to contents Left axis deviation may or may not be present.
    Back to contents Repolarization abnormalities of ST segment depression and T wave inversion suggesting ventricular strain may be present in the left chest leads with tall R waves. (See leads V5 and V6 in above ECG.)
    Back to contents Signs of left atrial enlargement in leads II, III, aVF or V1 may be present. Left atrial abnormality is the result of having to pump blood into a muscular non-compliant left ventricle.

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