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Category: Volume 06 Issue 01 January 2018
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Title: A Comparison Study of QT Dispersion in Early and Delayed Thrombolytic Therapy in Acute ST Elevation Myocardial Infarction

Authors: Muralidharan Azhakesan, Thanalakshmi Balachandran, Sindhu Neelakandan

 DOI:  https://dx.doi.org/10.18535/jmscr/v6i1.158

Abstract

Introduction: In analysis of Global burden of disease there is a shift from communicable to non communicable disease. Ischemic heart disease causes more death and disability than any other illness in the developed  world.. With urbanisation, in countries with emerging economies, the prevalence of risk factors for IHD and the prevalence of IHD itself are both increasing(17). Obesity, Insulin resistance and Type 2 Diabetus mellitus are Powerful risk factors for IHD. Population subgroups that appear to be particularly affected are men in South Asian countries, especially India and the Middle East.  IHD is likely to become the most common cause of death worldwide by 2020. In United States 13 million persons have IHD and more than 7 million have sustained a Myocardial infarction(17).

QTc and QTd are important parameters to predict mortality in patients with Acute STEMI. Many studies have evaluated the role 0f QTd  and risk of Ventricular Arrhythmias in Acute STEMI. In this study we try to to emphasize that early thrombolytic therapy reduces QTd in Acute STEMI.

Methods: This study is conducted among 100 patients diagnosed with STEMI admitted in ICCU within 12 hrs of onset of symptoms at Kanyakumari Government medical college hospital .Patients with typical chestpain (more than 30 minutes),ST elevation >1mm in 2 or more limb leads, ST elevation >2mm in 2 or more precordial leads ,No contraindications for thrombolysis were included in the study.

Patients on drugs which prolong QT like Quinidine,  Procainamide, Amiodarone, Sotalol ,TCA, Antihistamines astemizole, Azole Antifungals ,Drugs which reduce the QT like Digitalis, Patients with congenital long QT syndrome, Patients with Electrolyte disturbances, Patients with Atrial fibrillation, Bundle branch block, Patients with Acute carditis were excluded from the study.

Patients with STEMI admitted within 12hrs of onset of symptoms were enrolled, A standard 12 lead ECG was taken with paper speed of 25mm/sec at admission. Patients were treated with thrombolytic agent (streptokinase). Patients were divided in to patients treated with early thrombolysis within 3 hrs of onset of chest pain and lysed after 3 hrs of onset of pain.,ECGs are taken after thrombolysis (90mins from the beginning of thrombolysis), after 24hrs and before discharge. QT, QTc ,QTd, QTdc were calculated in patients admitted with STEMI and the difference of QT parameters in patients treated with early thrombolysis and in patients thrombolysed late due to delayed presentation were analysed

Results: In our study mean age of study subjects is 60.7 in early lysis group and 59.65 in late lysis group. Among 100 patients studied 40 patients were Diabetics, 36 patients were Hypertensives and 36 patients were smokers. Mean QT dispersion is 111ms in early lysis group and 120ms in late lysis group which is not significant statistically. Post lysis QT after 30mins of thrombolysis is 70ms in Early lysis group and 110ms in late lysis group which is statistically significant with the P value of 0.007. Mean QTd on the 2nd day of thrombolysis is 60ms in early lysis group and 110ms in late thrombolysis group which is statistically significant with the P value of 0.0001. Mean QTd at the time of discharge is 50ms in early thrombolysis group and 100ms in late thrombolysis group which is statistically significant with the P value of 0.0001.

In our study when the TIMI score is high the QT Maximum and QTd also high with a significant P value. When the TIMI score is low The QT value is also low with a significant P value.

Conclusion: Markers of autonomic regulation of heart like QTd provides valuable information about the future course of events in a patient following acute STEMI which can be utilized to plan the future course of management in patients especially predisposed to adverse and catastrophic outcomes.

when the TIMI score is high the QT Maximum and QTd also high which predicts increased mortality

QTd significantly reduces in early and successful thrombolysis than late and failed thrombolysis which in turn prevent the risk of arrhythmias

Keywords: QT, QTc, QTd, QTdc, Acute STEMI, TIMI score.

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Corresponding Author

Muralidharan Azhakesan

Assistant Professor, Department of Cardiology,

Kanyakumari Government Medical College Hospital