Yamamoto T, Nambu Y, Bo R, Morichi S, Yanagiya M, Matsuo M, Awano H. Electrocardiographic R wave amplitude in V6 lead as a predictive marker of cardiac dysfunction in Duchenne muscular dystrophy.
J Cardiol 2023;
82:363-370. [PMID:
37481234 DOI:
10.1016/j.jjcc.2023.07.003]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 07/11/2023] [Accepted: 07/14/2023] [Indexed: 07/24/2023]
Abstract
PURPOSE
Duchenne muscular dystrophy (DMD) is an inherited muscular disease characterized by progressive and fatal muscle weakness. Electrocardiographic (ECG) abnormalities, including abnormal R wave amplitudes are frequently observed in DMD. However, clinical implications of abnormal R wave amplitudes remain unclear. Hence, DMD patients were examined for changes in R wave amplitude over time using synthesized 18-lead ECG and the relationship between R wave amplitude and cardiac function.
METHODS
The results of 969 ECG examinations of 193 patients with DMD who underwent electrocardiography and echocardiography on the same day were retrospectively reviewed.
RESULTS
A negative correlation was observed between R wave amplitude and age. Positive correlations between R wave amplitude and left ventricular ejection fraction were observed in leads V4, V5, V6, syn-V7, syn-V8, and syn-V9, with V6 showing the strongest correlation (r = 0.52). Mean R wave amplitude during cardiac dysfunction was lower than that observed with preserved cardiac function in leads V6 to syn-V9. Patients had preserved R wave amplitude up to three years before the onset of cardiac dysfunction, with a sharp decrease two years before cardiac dysfunction in leads V6 to syn-V9.
CONCLUSIONS
In DMD patients, the R wave amplitude decreases with age. The sharp decline in R amplitude two years before cardiac dysfunction indicates that electrophysiological damage to the myocardium of the left ventricle lateral to the posterior wall precedes the finding of cardiac dysfunction. The R amplitude in V6 of the standard 12-lead ECG is a convenient predictive marker of cardiac dysfunction, similar to that of the 18-lead ECG.
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