Investigating Electrocardiographic Abnormalities in Patients with Coronary Microvascular Dysfunction

BACKGROUND: Coronary microvascular dysfunction (CMD) is a frequently overlooked and underdiagnosed mechanism of cardiac ischemia despite its heightened risk of major adverse cardiovascular events. The potential impact of CMD on the conduction system and occurrence of arrhythmias has received limited attention. This study aimed to examine the link between CMD and surface electrocardiography (ECG). METHODS: We harnessed the Coronary Microvascular Disease registry (CMDR), utilizing the CoroVentis CoroFlow System (Abbott) to invasively assess patients presenting with symptomatic chest pain. All patients underwent microvascular assessment of the left anterior descending artery territory. Our cohort was stratified into two groups, CMD-positive and CMD-negative, with an analysis of the most recent ECG performed prior to the invasive evaluation for each patient. RESULTS: Our cohort comprised 230 patients, of which 60 were classified as CMD-positive and 170 as CMD-negative. T-wave inversion was observed in 30.5% of CMD-positive patients compared to 20% in the CMD-negative group (P=0.09), and ST depression was identified in 6.7% of CMD-positive patients compared to 2.4% of CMD-negative patients (P=0.12). There were no differences in conduction disorders, such as left bundle branch block (LBBB), left anterior hemiblock (LAHB), left posterior hemiblock (LPHB), right bundle branch block (RBBB), incomplete right bundle branch block (ICRBBB), and bifascicular block, between the two groups. There were no discernible distinctions in the ECG intervals, including the PR, QRS, and QT. There was a trend of increased left ventricular hypertrophy (LVH) according to the ECG criteria in patients with CMD (11.7% vs. 5.3%; P=0.09). CONCLUSION: Our study revealed a tendency toward ischemic and hypertrophic ECG changes among CMD-positive patients, but no differences in the occurrence of conduction disorders in patients with and without CMD. REGISTRATION: URL: https://clinicaltrials.gov; Unique Identifier: [NCT05960474][1] GRAPHIC ABSTRACT: A graphic abstract is available for this article. ### Competing Interest Statement Disclosures Hayder D. Hashim reports serving on the advisory boards of, and being a speaker for, Abbott Vascular, Boston Scientific, and Philips IGT. Ron Waksman reports serving on the advisory boards of Abbott Vascular, Boston Scientific, Medtronic, Philips IGT, and Pi-Cardia Ltd.; being a consultant for Abbott Vascular, Biotronik, Boston Scientific, Cordis, Medtronic, Philips IGT, Pi-Cardia Ltd., Swiss Interventional Systems/SIS Medical AG, Transmural Systems Inc., and Venous MedTech; receiving institutional grant support from Amgen, Biotronik, Boston Scientific, Chiesi, Medtronic, and Philips IGT; and being an investor in MedAlliance and Transmural Systems Inc. Brian C. Case Speaker: Zoll Medical. All other authors None. ### Clinical Trial Unique Identifier: [NCT05960474][1] ### Funding Statement None. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The design and conduct of the registry strictly adhered to the MedStar Health Institutional Review Board (IRB). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Data from the manuscript is available upon request. [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT05960474&atom=%2Fmedrxiv%2Fearly%2F2024%2F04%2F22%2F2024.04.21.24306154.atom