The ECG is very insensitive, albeit specific, for the diagnosis of LVH, and echocardiography is considered to be the "gold standard". When used as a screening test for the presence of LVH in the Framingham cohort, the ECG had maximum sensitivities of 19%, as shown below. Nevertheless, the ECG performs better in hospitalized patients who have a much higher pre-test probability of having disease than in the general population.
Because of the high prevalence of LVH in patients with LBBB, this diagnosis is usually inferred. Echocardiography is the preferred method of diagnosing LVH in LBBB. The W-P-W pattern commonly gives a false positive sign for LVH.
Recommended criteria for the ECG diagnosis of LVH:
The best performer for the diagnosis of LVH is the Cornell product, which is the Cornell voltage times the QRS duration. This criterion takes advantage of the fact that the two unequivocal accompaniments of LVH are increased QRS voltage and a prolonged QRS duration. However, a calculator is required for this criterion, so I do not recommend it. The next best performer is the Cornell voltage, the sum of the R wave amplitude in lead aVL and the S wave depth in lead V3, adjusted for sex. Because the R wave height criteria are very specific, and comprise half of the Cornell voltage, I recommend that you start with aVL. Application of the criteria below in the order listed will diagnose, most cases of LVH.
Approach to LVH diagnosis:
Performance of several voltage criteria for the diagnosis of LVH, using data from the Framingham study:
Subjects included 1468 men and 1883 women, totaling 3351. There were no adjustments for age or obesity. Criteria are arranged in order of descending sensitivity. LR+ = positive likelihood ratio (sens/ 1-spec); LR- = negative likelihood ratio (1-sens/spec)
Diagnosis of LVH in LAFB:
Whenever there is left axis deviation, lead aVL must have the tallest R wave height and lead III the deepest S wave depth in the limb leads. These changes may result in false positive LVH voltages. The table below shows the R and S amplitudes in leads aVL and III in patients with LAFB, LVH and LVH with LAFB, compared with normal subjects.
Recommended criteria: S III + maximum RS amplitude in any precordial lead > 30 mm or an R in aVL > 13 mm.
Repolarization abnormalities in LVH:
In the Framingham cohort, LVH voltage with typical ST-T wave abnormalities ("strain") conferred a doubling of the risk of death due to stroke or myocardial infarction. Therefore, one should regard typical repolarization abnormalities in the presence of LVH as an ominous sign of end-organ damage.
Because the left ventricle is the dominant ventricle in LVH, it determines most major ECG waveforms. Whenever there is an abnormality of the dominant ventricle, all leads should reflect this abnormality. Therefore, if there is LVH with typical repolarization abnormalities, all leads should reflect these abnormalities.
The rule that applies to abnormalities of repolarization in LVH:
The ST segment and T wave are directed opposite to the dominant QRS waveform in all leads. However, the T wave axis usually differs from the QRS axis, so that one should not apply the directional rule either in the transitional lead (defined as having an R wave height equal to the S wave depth) or in the transitional zone (defined as leads adjacent to the transitional lead) or one lead to the left in the precordial leads.
The spectrum of repolarization abnormalities in LVH:
The waveforms below, usually seen in leads I, aVL, V5 and V6, but more specifically in leads with dominant R waves, represent hypothetical stages in the progression of LVH.
Back to Index