Babu, K (2008) Study of Clinical Profile of 50 Patients with Acute Inferior Wall Myocardial Infarction. Masters thesis, Stanley Medical College, Chennai.
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Abstract
INTRODUCTION: Myocardial infarction is the term used when the myocardium is necrosed due to ischemia. It may be transmural or subendocardial. Patients with ischaemic heart disease fall into two large groups. Patients with stable angina and patients with acute coronary syndromes (ACS). ACS group in turn is composed of patients with acute myocardial infarction with ST elevation (STEMI), those with unstable angina (UA) and non ST segment elevation MI (NSTEMI). Inferior wall infarction has got some special features like association with right ventricular infarction and bradyarrhythmias especially sinus bradycardia and second degree AV block. Right Ventricular infarction is different from that of the left ventricle in the acute presentation, therapy and long term prognosis. The early recognition of RVI is important, because the time of onset of its haemodynamic consequence is unpredictable and these may be prevented by the administration of intravenous fluid load. The description of RVI appeared more than 60 years ago. But it was considered unimportant until Cohn and Co-workers in 1974 published their classic report on RVI as a distinct clinical entity. The reported incidence is between 25 – 50% of IWMI. Involvement of RV is related to atherosclerotic occlusion of the right coronary artery and is associated with involvement of postero-inferior wall and posterior portion of the septum. Clinically RVI can be suspected when a patient with IWMI presents with elevated JVP, positive Kussmaul’s sign, hypotension, right sided third or fourth heart sounds, tender hepatomegaly, oliguria, rarely tricuspid regurgitation and clear chest. Electrocardiogram was generally believed to be unhelpful in identifying RVI, until Erhardt and co-workers described the value of a right precordial lead in patients with autopsy proved RVI. A 1 mm ST elevation in this lead is 93% sensitive and 95% specific. The change is transient. In one series, 48% of the patients had resolution of ECG changes within 10 hours of the onset of symptoms. AIM OF THE STUDY: To study the clinical profile of 50 serial cases of Acute Inferior Wall Myocardial Infarction with Right Ventricular Infarction and to analyse the age and sex distribution, symptomatology, clinical features, complications and outcome. MATERIALS AND METHODS: This study was conducted during December 2006 to July 2007 period. 50 consecutive patients admitted to the coronary care unit with a diagnosis of acute inferior wall infarction were included in the study. All patients included in the study were subjected to ECG examination of V3R and V4R in addition to the conventional 12 leads. In addition, all patients were subjected to ECG examination of extended leads V7 to V9. Rhythm strips were taken in patients with arrhythmias. ECGs were examined at the time of admission, second day and on the day of discharge. Only those cases with hyperacute inferior wall infarction were included in the study. Patients with slope elevation of ST segment in leads, II, III and aVF were taken as having hyperacute inferior wall infarction. Right ventricular infarction was diagnosed if there was ST elevation equal to or more than 1 mm in V4R. Posterior wall myocardial infarction was diagnosed if there was ST segment elevation equal to or more than 1 mm in extended leads V7 to V9,with tall ‘R’, ST segment depression, upright ‘T’ in leads V1,V2. All patients were assessed clinically and electrocardiographically with special emphasis on presenting complaints, risk factors, vital signs, arrhythmias and mortality. Patients were followed up till discharge. Patients who presented after 24 hrs of onset of chest pain were excluded, as the ST changes in right ventricular infarction may be transient. Patients with history of chronic lung disease, previous MI, rheumatic heart disease, pericardial disease or LBBB were excluded because diagnosis of right ventricular infarction is not possible in these cases when ECG is used as the criteria. RESULTS: The observations in 50 patients with acute inferior wall myocardial infarction is presented in this section in descriptive and tabular form. Cases were divided in to groups of 5 years difference for comparing age and sex incidence. Peak incidence was found in 2 groups, one group with mean age 42 and another with mean age 62. The lowest age was 31 years who was a male. The patient with highest age was a female of 82 years. 41 patients were male and 9 were female. CONCLUSION: 1. The incidence of Acute Inferior Wall Myocardial Infarction is much higher in males than in females, the difference being less as age advances. 2. In males, there is a distinct increase in the incidence after age of 40 years in this study. 3. Typical retrosternal chest pain lasting for more than 30 minutes associated with sweating was seen in almost all patients. 4. Smoking was the most prevalent risk factor (56%). 5. The onset of symptoms in majority of the patients (60%) was between 6 am – 12 noon. 6. The incidence of Right ventricular infarction in this study was 38%. 7. Syncope or presyncope was a prominent symptom in patients with right ventricular infarction. 8. Triad of raised JVP, Hypotension and clear lung fields were seen in 15 patients (30%). 9. All cases of inferior wall infarction should have right-sided leads during ECG examination and this should be done as early as possible. 10. If diagnosis of RVMI is correctly made and treated early, the prognosis is usually good. 11. Incidence of true posterior wall myocardial infarction in this study was 16%. 12. Mortality is higher in patients with right ventricular infarction when compared with those without this complication.
| Item Type: | Thesis (Masters) |
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| Uncontrolled Keywords: | Acute Inferior Wall Myocardial Infarction ; Clinical Profile ; 50 Patients. |
| Subjects: | MEDICAL > General Medicine |
| Depositing User: | Subramani R |
| Date Deposited: | 23 Mar 2018 15:57 |
| Last Modified: | 23 Mar 2018 15:57 |
| URI: | http://repository-tnmgrmu.ac.in/id/eprint/6470 |
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