Utility of Left Bundle Branch Block as the Diagnostic Criterion for Myocardial Infarction in a Hemodynamically Stable Patient

Ashok, S (2016) Utility of Left Bundle Branch Block as the Diagnostic Criterion for Myocardial Infarction in a Hemodynamically Stable Patient. Masters thesis, Coimbatore Medical College, Coimbatore.

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Abstract

OBJECTIVE: Prompt and accurate identification of ST-elevation myocardial infarction (STEMI) in the presence of left bundle-branch block (LBBB) remains difficult. Repolarization in LBBB is characterized by ST segment deviation away from the direction of the terminal QRS waveforms. Therefore, the ECG manifestations of STEMI may be either obscured or mimicked by the baseline secondary ST-segment deviations of LBBB. It is often unclear which emergency department (ED) patients with potentially ischemic symptoms actually have an acute myocardial infarction (AMI), even in the setting of LBBB. My study is aimed at finding the incidence of Myocardial Infarction in new onset LBBB comparing it with the incidence of AMI in old LBBB and whether new onset LBBB predicts increased likelihood of myocardial infarction. METHODS: This was a prospective observational study. Patients older than 30 years who presented with chest pain or other ischemic equivalent and had an electrocardiogram (ECG) to evaluate potential acute coronary syndrome (ACS) were enrolled. Data collected include demographics, history, ECG, and cardiac markers. Electrocardiograms were classified according to the standardized guidelines, including LBBB not known to be old (new or presumed new LBBB), LBBB known to be old, or no LBBB. The hospital course was followed, and 30-day follow-up was performed on all patients. Our main outcome was AMI. RESULTS: Among the 50 patient selected for study 23 had new onset LBBB and 27 had old LBBB. 73.9% of the patients with new onset LBBB were older than 50 years of age and 96.3% of the patients with old LBBB were more than 50 years of age. 8.7% of the people with new LBBB were troponin positive while 7.4% of the patient with old LBBB had Troponin. CONCLUSION: There is no difference in the incidence of Myocardial Infarction in the patients with old LBBB and new onset LBBB. Hemodynamically stable Patients with suspected Acute Coronary Syndrome and new onset LBBB are not at increased risk of AMI. Presence of LBBB whether new or old LBBB did not predict acute myocardial Infarction. Algorithmic approach towards a suspected Acute coronary syndrome should take into consideration hemodynamic status ,whether patient is in acute heart failure AND whether ECG fits into Smiths criteria and if any of them is present, decision for reperfusion should be promptly taken. 8.7% of the people with new LBBB were troponin positive while 7.4% of the patient with old LBBB had Troponin.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Left Bundle Branch Block ; Diagnostic Criterion ; Myocardial Infarction ; Hemodynamically Stable Patient.
Subjects: MEDICAL > General Medicine
Depositing User: Subramani R
Date Deposited: 06 Feb 2019 02:12
Last Modified: 06 Feb 2019 02:12
URI: http://repository-tnmgrmu.ac.in/id/eprint/10497

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