[Evaluation of inferior wall myocardial infarctions by ECG using 5 unipolar retrocardial leads in addition to the standard 12 leads].

OBJECTIVE: This study was planned to evaluate the change patterns in 5 unipolar retrocardial leads (taken from back) in addition to standard 12 leads ECG in subjects with inferior myocardial infarction (IMI) and to see whether these patterns, if there are any, could be useful to assess the cases with IMI.

METHODS: A hundred forty two cases were included to study. At first, in order to determine the normal ECG configurations in 5 unipolar retrocardial leads 30 subjects with normal standard 12 lead ECG and normal physical findings were studied. The normal configurations of retrocardial leads were then determined and retrocardial leads were expressed as RE1-5. Later, 60 subjects with chronic IMI and 52 with acute IMI were evaluated.

RESULTS: The QS or Qr in VRE1, QR or qR in VRE2, qRs in VRE5 and transitional patterns in VRE3-4 were accepted as normal configurations of the retrocardial leads. Pre- and retrocardial derivations of 60 cases who had old IMI were normal in 21(35%) cases. There were pathologic Q waves in VRE1-VRE2 leads in 5 (8.3%) cases, in VRE3-VRE4 leads in 11(18.3%) cases, in V5-V6 and VRE5 leads in 3 (5%) cases, in V5-V6 and VRE1-VRE5 leads in 12 (20%) cases, in VRE1-VRE4 leads in 8 (13.3%) cases. Pre- and retrocardial leads of 52 cases with acute IMI were normal in 10 (19.5%) cases. There were ST segment depression in V1-V2 and ST segment elevation in VRE-VRE2 leads in 4 (7.6%) cases, ST segment depressions in V3-V4 derivations and ST segment elevations in VRE3-VRE4 leads in 5 (9.6%) cases, ST segment depression in V2-V6, VRE5 leads and ST segment elevation in VRE1-VRE4 leads in 8 (15.3%) cases, ST segment depression in V1-V4 leads and ST segment elevations in RE1-VRE4 in 12 (23%) cases. ST segment depression in V1-V4 leads and ST segment elevation in V5-V6 and VRE1-VRE5 were found in 13 (25%) cases.

CONCLUSION: According to ECG findings which were taken from pre- and retrocardial leads of IMI cases were classified as follows; ST elevation or Q wave or both in DII, DIII, AVF(-)+; 1--Pre and retrocardial leads are normal; 2--ST depression in V1 (sometimes ST elevation if there is right ventricular involvement)--V2, ST elevation or Q wave or both in VRE1-VRE2); 3--ST depression in V3-V4 and ST elevation or Q wave or both in VRE3-VRE4); 4--ST depression in V1-V4 and ST elevation or Q wave or both in VRE1-VRE4); 5--ST depression in V1-V4, ST elevation or Q wave or both inV5-V6 and ST elevation or Q wave or both in VRE1-VRE5); 6--ST depression in V1-V6 and ST elevation or Q wave or both in VRE1-VRE4 and ST depression in VRE5). It is concluded that, in addition to standard 12 lead ECG, retrocardial 5 leads could be recorded and interpreted easily. ECG patterns taken from 5 unipolar retrocardial leads in patients with IMI are not homogeneous. Different groups of ECG findings in certain leads were determined. Further investigations to clarify these different groups ECG findings are needed and these might bring a new approach to assess the subjects with IMI.