Investigating electrocardiogram and certain biomarkers as diagnostic methodologies to assist in the diagnosis of mitral valve prolapse

Abstract

Introduction: Mitral valve prolapse (MVP) is a common valvular abnormality of the heart and echocardiography remains the gold standard for the diagnosis. Unfortunately, echocardiography is only available at tertiary hospitals and private internal medicine and cardiology practices and requires qualified echocardiographers to operate it. According to my knowledge and personal experience the public sector in South Africa and private healthcare in rural areas do not provide this service and are compelled to refer patients externally for an echocardiogram. They do however have access to electrocardiogram (ECG) equipment, which is cost effective. To conduct an ECG requires minimum training and experience, but the interpretation of an ECG requires in depth pathophysiology knowledge and training and thus needs to be done by a medical professional. Early MVP diagnosis is of great importance, since complications of MVP include syncope, infective endocarditis, arrhythmias, cerebral vascular ischaemic events, and sudden death. Although studies in various populations from other countries have reported ECG changes in patients with MVP, similar studies have not been reported in any South African population. Aim: Can ECG derived parameters identify persons with possible prolapse that will then be referred for echocardiographic investigations? The aim of the study was to investigate the possibility of using ECG criteria as a potential diagnostic methodology for MVP and to determine if (NT-proBNP), Troponin I and C-reactive protein (CRP) could assist in the diagnosis of MVP. Methods: This is a retrospective observational study and convenient purposive sampling was done. A total of 89 subjects were selected that met the inclusion and exclusion criteria and had ECG’s and Echocardiograms done as part of their cardiac workup. The P wave amplitude, P wave duration, P-R interval, QRS complex duration, J point (early repolarisation), T wave duration and QT and QTc intervals were calculated. The NT-proBNP, CRP and Troponin I results were retrieved. These findings were compared with the ECG and pathology results of 30 healthy subjects in the control group to determine if there is a statistical correlation between any of these factors individually or combined, and the MVP subjects. Results: Early repolarisation was detected in the MVP group. Other statistically significant ECG markers were the P wave amplitude, P wave duration, QRS duration and the QT interval. The NT-proBNP and Troponin I biomarkers were not statistically different to the controls. Although 50% of the subjects had elevated CRP levels, CRP is a non-specific marker of inflammation such as endocarditis. It might thus be beneficial to determine CRP levels since increased CRP levels in MVP patients may also be suggestive of inflammatory processes involved in the pathology of MVP. Conclusion: Although the P wave amplitude, P wave duration, QRS duration and the QT interval showed statistical significance, all the ECG values were within the normal range of ECG parameters. Therefore, ECG would not be recommended as a diagnostic tool for MVP.