Electrocardiographic diagnosis of left ventricular hypertrophy in the presence of bundle branch block

Usefulness of ECG criteria to rule out left ventricular hypertrophy in older individuals with true left bundle branch block: an observational study

Background

Advanced age is associated with both left bundle branch block (LBBB) and hypertension and the usefulness of ECG criteria to detect left ventricular hypertrophy (LVH) in patients with LBBB is still unclear. The diagnostic performance and clinical applicability of ECG-based LVH criteria in patients with LBBB defined by stricter ECG criteria is unknown. The aim of this study was to compare diagnostic accuracy and clinical utility of ECG criteria in patients with advanced age and strict LBBB criteria.

Methods

Retrospective single-center study conducted from Jan/2017 to Mar/2018. Patients undergoing both ECG and echocardiogram examinations were included. Ten criteria for ECG-based LVH were compared using LVH defined by the echocardiogram as the gold standard. Sensitivity, specificity, predictive values, likelihood ratios, AUC, and the Brier score were used to compare diagnostic performance and a decision curve analysis was performed.

Results

From 4621 screened patients, 68 were included, median age was 78.4 years, (IQR 73.3–83.4), 73.5% with hypertension. All ECG criteria failed to provide accurate discrimination of LVH with AUC range between 0.54 and 0.67, and no ECG criteria had a balanced tradeoff between sensitivity and specificity. No ECG criteria consistently improved the net benefit compared to the strategy of performing routine echocardiogram in all patients in the decision curve analysis within the 10–60% probability threshold range.

Conclusion

ECG-based criteria for LVH in patients with advanced age and true LBBB lack diagnostic accuracy or clinical usefulness and should not be routinely assessed.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-021-02332-8.

Are classic predictors of voltage valid in cardiac amyloidosis? A contemporary analysis of electrocardiographic findings

BACKGROUND

Low voltage electrocardiography (ECG) coupled with increased ventricular wall thickness is the hallmark of cardiac amyloidosis. However, patient characteristics influencing voltage in the general population, including bundle branch block, have not been evaluated in amyloid heart disease.

METHODS

A retrospective analysis was performed of patients with newly diagnosed cardiac amyloidosis from 2002 to 2014. ECG voltage was calculated using limb (sum of QRS complex in leads I, II and III) and precordial (Sokolow: S in V1 plus R in V5-V6) criteria. The associations between voltage and clinical variables were tested using multivariable linear regression. A Cox model assessed the association of voltage with mortality.

RESULTS

In 389 subjects (transthyretin ATTR 186, light chain AL 203), 30% had conduction delay (QRS >120ms). In those with narrow QRS, 68% met low limb, 72% low Sokolow and 57% both criteria, with lower voltages found in AL vs ATTR. LV mass index as well as other typical factors that impact voltage (age, sex, race, hypertension, BSA, and smoking) in the general population were not associated with voltage in this cardiac amyloidosis cohort. Patients with LBBB and IVCD had similar voltages when compared to those with narrow QRS. Voltage was significantly associated with mortality (p<0.001 for both criteria) after multivariable adjustment.

CONCLUSION

Classic predictors of ECG voltage in the general population are not valid in cardiac amyloidosis. In this cohort, the prevalence estimates of ventricular conduction delay and low voltage are higher than previously reported. Voltage predicts mortality after multivariable adjustment.

Effect of right bundle branch block on electrocardiographic amplitudes, including combined voltage criteria used for the detection of left ventricular hypertrophy

BACKGROUND

Although right bundle branch block (RBBB) delays right ventricular depolarization, its effect on cancellation of right and left ventricular forces within the QRS complex has not been quantified during stable temporal and physiological conditions. Systematic changes in QRS amplitude during transient RBBB bear directly on performance of standard ECG criteria for left ventricular hypertrophy (LVH), and these changes require quantification.

METHODS

We examined the instantaneous effect of RBBB on QRS amplitudes and LVH voltages in 40 patients who had intermittent complete RBBB during a single 10 sec standard 12-lead ECG recording, comprising 0.1% of approximately 400,000 consecutive ECGs in a university teaching hospital setting. Amplitudes were measured by magnifying graticule to the nearest 25 microvolts, averaged for up to 3 normal and 3 RBBB complexes, and compared by paired t test.

RESULTS

RBBB was associated with an increase in initial QRS forces (RV1, RV2, and QV6) but significant decreases in mean mid-QRS amplitudes that reflect left ventricular depolarization (RaVL [-75 microvolts], SV1 [-389 microvolts], SV3 [-617 microvolts], RV5 [-100 microvolts], and RV6 [-123 microvolts]). All late QRS forces were increased with RBBB (R'V1, SV5, SI). As a result, combined voltages used for LVH criteria were significantly reduced by RBBB: Sokolow-Lyon voltage decreased from 1520 +/- 739 to 1014 +/- 512 microvolts (p < 0.001), and Cornell voltage decreased from 1438 +/- 683 to 746 +/- 399 microvolts (p < 0.001).

CONCLUSIONS

RBBB is associated with significant reduction in "left ventricular" QRS amplitudes of the standard ECG, consistent with cancellation, rather than unmasking, of left ventricular mid-QRS forces by altered septal and delayed right ventricular depolarization. Because QRS voltages that are routinely combined for the detection of LVH are reduced in RBBB, standard LVH criteria will perform with lower sensitivity in patients with RBBB.

Clinical implication of left precordial T wave inversions in the presence of complete right bundle branch block

This study was designed to elucidate whether left precordial negative T waves are electrocardiographic indicators for the diagnosis of hypertrophic cardiomyopathy (HCM) even in the presence of complete right bundle branch block (CRBBB). In 7 consecutive patients with CRBBB accompanied by negative T waves in at least one of the left precordial leads (V4, V5, V6, maximal negativity; 1.06 +/- 0.40 mVol) (left precordial negative T wave group) and in 15 randomly selected CRBBB patients without left precordial T wave inversions (control group), echocardiography was performed to rule out underlying diseases causing left ventricular overload and to identify candidates for magnetic resonance (MR) imaging. None had anginal pain indicating ischemic heart disease. When 2-dimensional echocardiography indicated left ventricular hypertrophy with wall thickness > or = 15 mm, the magnitude and distribution of hypertrophy were scrutinized on contiguous left ventricular MR short-axis images. The diagnostic criterion of HCM was the demonstration of hypertrophy with a wall thickness of 20 mm or more on the left ventricular MR short-axis images. All patients in the left precordial negative T wave group had negative T waves in both I (negativity; 0.27 +/- 0.17 mVol) and aVL (negativity; 0.23 +/- 0.14 mVol), whereas none in the control group did. The diagnostic criterion for HCM was fulfilled in six patients in the left precordial negative T wave group. However there were no patients who fulfilled the criterion in the control group. Negative T waves were recorded in the I (negativity; 0.30 +/- 0.17 mVol), aVL (negativity; 0.25 +/- 0.14 mVol), V4 (negativity; 1.03 +/- 0.46 mVol), V5 (negativity; 0.83 +/- 0.37 mVol) and V6 leads (negativity; 0.31 +/- 0.31 mVol) in all patients with HCM, while they were recorded in only 6% of the patients without HCM. In conclusion, the existence of left precordial negative T waves in the presence of CRBBB strongly indicates HCM.

Right bundle branch block: varying electrocardiographic patterns. Aetiological correlation, mechanisms and electrophysiology

Ten dissimilar electrocardiographic (ECG) patterns associated with right bundle branch block (RBBB) are presented. Electrophysiologic basis of the changes is discussed and possible causes for such diversity outlined. We have not found any aetiological association to this variation. The morphological diversity in RBBB patterns is likely to be related to multiple factors--site of block, nature of defect (functional, necrosis, fibrosis), degree of conduction delay, and associated pathologies with their own ECG patterns. Distinguishing RBBB from a normal ECG-variant like rsr' is particularly important when associated with left hemiblocks as the latter situation warrants extensive cardiac evaluation.

Electrocardiographic diagnosis of left ventricular hypertrophy in the presence of right bundle branch block in cases with essential hypertension

Right bundle branch block was diagnosed in electrocardiograms of 37 of 1085 patients with essential hypertension. Echocardiographically left ventricular hypertrophy was diagnosed in 14 of these 37 patients. Eighteen electrocardiographic (ECG) criteria, which were previously recommended, were determined in these 37 patients. The sensitivities of five criteria were found to be better than 50%. These are SV1 > or = 2 mm; RV6 > RV5; S III + (R+S) maximum precordial lead > or = 30 mm; P/PR > or = 1.6; R aVL > or = 11 mm. However, their specificities ranged from 56.5% to 95.6%. When the combination of RV6 > RV5 and S III + (R+S) maximum precordial lead > or = 30 mm was used, sensitivity was 57.1 and specificity was 100%. It is concluded that the presence of right bundle branch block these ECG criteria can be used for the diagnosis of left ventricular hypertrophy.