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Clinical implication of left precordial T wave inversions in the presence of complete right bundle branch block
J Suzuki1, W S Shin, R Shimamoto
1Department of Internal Medicine, Faculty of Medicine, University of Tokyo, Japan.
Insights
Left precordial negative T waves are strong indicators for diagnosing hypertrophic cardiomyopathy (HCM) even with complete right bundle branch block (CRBBB). This finding aids in identifying HCM in patients with CRBBB, improving diagnostic accuracy.
Area of Science:
- Cardiology
- Electrocardiography
- Cardiac Imaging
Background:
- Hypertrophic cardiomyopathy (HCM) diagnosis can be challenging, particularly with coexisting electrocardiographic abnormalities.
- Complete right bundle branch block (CRBBB) can complicate the interpretation of standard electrocardiogram (ECG) findings.
Purpose of the Study:
- To determine if left precordial negative T waves are reliable indicators for diagnosing HCM in patients with CRBBB.
- To assess the diagnostic value of specific ECG patterns in the context of CRBBB for HCM detection.
Main Methods:
- Compared 7 patients with CRBBB and left precordial negative T waves to 15 CRBBB patients without these T wave abnormalities.
- Utilized echocardiography to screen for left ventricular hypertrophy and magnetic resonance (MR) imaging for definitive HCM diagnosis (wall thickness ≥20 mm).
Main Results:
- Six of seven patients (86%) with CRBBB and left precordial negative T waves met the diagnostic criteria for HCM.
- None of the control CRBBB patients without left precordial T wave inversions were diagnosed with HCM.
- Negative T waves were present in leads I, aVL, V4, V5, and V6 in all diagnosed HCM patients with CRBBB.
Conclusions:
- Left precordial negative T waves are a significant indicator of HCM in the presence of CRBBB.
- This ECG finding can improve the diagnostic accuracy of HCM in patients with this specific conduction abnormality.
Abstract:
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.