What is the significance of tall peak to QRS (quantitative electrocardiogram measure) complexes in leads V4 and V5 on an electrocardiogram (ECG)?

From the Guidelines

Tall peak QRS complexes in leads V4 and V5 are indicative of left ventricular hypertrophy (LVH), a condition that requires further evaluation and management to prevent adverse cardiac outcomes. The significance of these findings lies in their association with underlying cardiac conditions such as hypertension, aortic valve disease, or hypertrophic cardiomyopathy 1. The increased QRS amplitude in leads V4 and V5 occurs due to the thickened ventricular wall generating stronger electrical forces during depolarization.

According to the American Heart Association electrocardiography and arrhythmias committee, council on clinical cardiology, diagnostic criteria for LVH are based on measurements of QRS voltages, with various criteria having been proposed over the years 1. The most commonly used criteria include the Sokolow-Lyon criterion, which is based on the sum of SV1 and RV5 or RV6, and the Cornell voltage criterion, which is the sum of SV3 and RaVL 1.

Some key points to consider when interpreting tall peak QRS complexes in leads V4 and V5 include:

• The sensitivity and specificity of the various criteria for diagnosing LVH, with sensitivity generally being low (less than 50%) and specificity being high (often in the range of 85% to 90%) 1
• The influence of factors such as age, gender, race, and body habitus on QRS voltages, which can contribute to the limited accuracy of ECG criteria for LVH 1
• The importance of clinical correlation and further evaluation, including echocardiography, to confirm the diagnosis and assess the degree of hypertrophy
• The need for treatment to target the underlying cause of LVH, such as blood pressure control for hypertension, with medications like ACE inhibitors, ARBs, or beta-blockers.

It is essential to note that tall QRS complexes may occasionally appear in healthy, athletic individuals due to physiologic adaptation rather than pathology, highlighting the need for careful interpretation of ECG findings in the context of the individual patient's clinical presentation 1.

From the Research

Significance of Tall Peak to QRS Complexes in V4 and V5

The significance of tall peak to QRS complexes in leads V4 and V5 on an electrocardiogram (ECG) is related to the diagnosis of left ventricular hypertrophy (LVH).

• LVH is a condition where the muscle wall of the left ventricle becomes thicker, which can be a precursor to heart failure 2.
• ECG criteria for LVH, such as the Sokolow-Lyon, Romhilt-Estes, and Cornell criteria, rely on assessing changes in the amplitude and/or duration of the QRS complex to quantify LV mass 3.
• Studies have shown that ECG criteria for LVH correlate poorly with both transthoracic echocardiograms and cardiac magnetic resonance imaging (CMR) 4.
• The Romhilt-Estes criteria demonstrated the strongest correlation with transthoracic echocardiograms, followed by Sokolow-Lyon, Modified Cornell, and Cornell criteria 4.
• CMR has emerged as a valuable tool for quantifying LV mass and detecting myocardial tissue characteristics, such as fibrosis, edema, and inflammation 3, 2.
• Echocardiography is also essential for the quantification and early detection of LV structural findings, and speckle-tracking echocardiographic parameters are useful for detecting early LV structural abnormalities 5.

Diagnostic Implications

• The diagnosis of LVH is crucial, as it can be a precursor to heart failure, and early detection and treatment can improve outcomes 2.
• A comprehensive assessment of LV systolic and diastolic function using echocardiography, CMR, and other imaging modalities can provide important clues to the final diagnosis and guide therapy and follow-up 2, 6.
• The characterization and quantification of LVH using echocardiography and CMR can allow for a more timely diagnosis of the underlying condition 6.