Prevalence, clinical , in - hospital complications & mortality of right ventricular infarction associated with inferior wall myocardial infarction.

Thesis Report.

ABSTRACT: OBJECTIVES To know the prevalence, clinical presentation, electrocardiographic and Echocardiographic features, in- hospital complications and mortality in patients of inferior wall myocardial infarction associated with right ventricular infarction. DESIGN Study of 53 consecutive patients with inferior wall myocardial infarction. SETTING TU Teaching Hospital and Bir Hospital Which are both tertiary referral centers in the country. METHODS 53 consecutive patients with acute inferior myocardial infarction were enrolled in the study. Right ventricular infarction was determined by the presence of ST elevation of more than 0.1 mv in V4R. All the patients were divided into two Groups. Group a consisted of patients on inferior wall MI with right ventricular infarction and Group -b consisted of patients of inferior wall MI without right ventricular infarction. clinical presentation electrocardiographic changes, echocardiographic findings complications and mortality of Group-A were compared with Group-B RESULTS The incidence of right ventricular infarction in inferior wall MI was found in 37.8% of cases in which 18 (90%) were male and 2(10%) were female with the mean age of 58.95± 11.13. Incidence of Hypotension, Positive kussmaul's Sign, cardiogenic shock, pulsus paradoxus were significantly higher in patients of Group-A compared to Group-B (P value-<0.001 in the first two and <0.05 and <0.01 in the last two parameters, respectively). The sum of ST segment elevation in led II, III and a VF was significantly higher in Group-A, Compared to Group-B (7.2±3.69 vs.5.17±3. 42; P value <0.05) when considered separately ST elevation in led III and a VF was significantly higher in Group-A compared to Group-B P value<0.05). In the right precordial lead v5R had the highest sensitivity (80%) with reasonable specificity of 94% Whereas lead v 3R had lowest sensitivity (55%) with highest specificity (97%). ST elevation in v6R was found to have lowest specificity for detection of right ventricular infarction. On echocardiographic examination dilatation of the right ventricule, ratio right ventricular end-diastolic diameter to left ventricular end-diastolic diameter, right ventricular wall motion abnormality and abnormal ventricular septal motion were found significantly higher in Group-A compared to Group-B.(P value <0.001 in the first three, and <0.05 in the last one respectively). Right ventricular wall motion abnormality was found to have highest sensitivity specificity and predictive accuracy for the diagnosis of right ventricular infarction (88.3%, 96.7%, 94.8% respectively). Complete heart block and junctional rhythm were the most common in-hospital complications found following RV infarction. and were significantly higher in patients with Group-A compared to patients of Group-B (P value <0.001 and <0.05). Mortality was 2(10%) in Group-A and 1(3.3%) in Group-B (statistically not significant). CONCLUSION Right ventricular infarction is found frequently at the setting of acute inferior wall myocardial infarction. Sequelae of RV infarction should be made from the presence of hypotension, raised jugular venous pulse, positive Kussmaul's sign, pulsus paradoxus, cardiogenic shock and high AV block with clear lungs. Early detection of RV infarction is very important because the time of onset of its heamodynamic deterioration is unpredictable, Prompt volume expansion with the use the normal saline may abort the vicious circle set in motion by RV infarction. ECG is the simple, cheap, readily available diagnostic aid with high sensitivity and specificity. ST elevation in right sided leads and Qs/Or pattern in lead V3R. and V4R have high predictive value for recognition of RV infarction. Two dimentional echocardiography is useful noninvasive diagnostic tool having high predictive value for detection of RV infarction. It is useful to rule out the conditions showing clinical features similar to RV infarction.

Eng.