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Left Ventricular Hypertrophy
Left ventricular hypertrophy (LVH) is an abnormal thickening of the left ventricular myocardium that occurs as an adaptive mechanism to increased afterload.
The left ventricular myocytes hypertrophy in order to gain contractile strength to overcome this increased afterload and distribute the wall stress throughout a larger mass thus decreasing oxygen demand (see Law of Laplace). Pathologic left ventricular hypertrophy can occur in the setting of hypertrophic obstructive cardiomyopathy even in the absence of increased afterload.
The ECG findings of left ventricular hypertrophy are multiple and usually include increased amplitude of the QRS complex. The most commonly used ECG criteria to diagnosed left ventricular hypertrophy (LVH) is below:
Cornell criteria: Add the R wave in aVL and the S wave in V3. If the sum is > 28 mm in males or > 20 mm in females, then LVH is present.
Modified Cornell Criteria: Examine the R wave in aVL. If the R wave is > 12 mm in amplitude, then LVH is present.
Sokolow-Lyon Criteria: Add the S wave in V1 plus the R wave in V5 or V6. If the sum is > 35 mm, then LVH is present.
Romhilt-Estes LVH Point Score System:
If score = 4, then LVH present with 30-54% sensitivity. If score > 5, then LVH is present with 83-97% specificity.
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Amplitude of largest R or S in limb leads >20 mm Amplitude of S in V1 or V2 > 30 mm Amplitude of R in V5 or V6 > 30 mm ST and T wave changes opposite QRS without digoxin ST and T wave changes opposite QRS with digoxin Left Atrial Enlargement Left Axis Deviation QRS duration > 90 milliseconds Intrinsicoid deflection in V5 or V6 > 50 millisecond |
3 3 3 3 1 3 2 1 1 |
When the myocardium as abnormally thickened, electrical activity takes longer to traverse throughout the whole heart, thus the duration of the QRS complex may be widened. This is referred to as "LVH with QRS widening". Also, repolarization may be affected via similar mechanisms which can result in abnormal ST segments or T waves. This is referred to as "LVH with strain" or "LVH with repolarization abnormality".
At times these repolarization abnormalities can mimic ischemic ST changes, so distinguishing them from those during a myocardial infarction is important, though often difficult. The typical pattern with LVH includes deviation of the ST segment in the opposite direction of the QRS complex (discordance) and a typical T wave inversion pattern is present (see below).
RELATED LINKS
Left Ventricular Hypertrophy (Example 1)
Left Ventricular Hypertrophy (Example 2)
Left Ventricular Hypertrophy (Example 3)
Left Ventricular Hypertrophy (Example 4)
Left Ventricular Hypertrophy (Example 5)
Left Ventricular Hypertrophy (Example 6)
Left Ventricular Hypertrophy With Strain Pattern (Example 1)
Left Ventricular Hypertrophy With Strain Pattern (Example 2)
Left Ventricular Hypertrophy With Strain Pattern (Example 3)
Left Ventricular Hypertrophy With Strain Pattern (Example 4)