Felizen S. Agno, M.D., Inna Nelipovich, M.D., Dipan Desai, D.O., Jason Gluck, D.O., Gorgi Kozeski, D.O., Ola Akinboboye, M.D., New York Hospital Queens, Flushing, NY
Background: Electrocardiographic (ECG) criteria for the diagnosis of posterior wall infarction (PWI) traditionally include R/S ratio in leads V1 or V2 > 1 and R wave duration in V1 ³ 40 ms in the absence of right axis deviation. In addition, the direction of T-wave in V1 and V2 was also found to be useful for the diagnosis of PWI. However, limited studies are available that assessed these criteria.
We conducted a retrospective analysis of 84 patients and correlated the standard ECG criteria for the diagnosis of PWI to the presence of inferobasal wall infarction (IBWI) using 99mTc Sestamibi SPECT myocardial perfusion imaging. We reviewed standard 12-lead ECG performed within 2 days of the stress test. We excluded patients with ventricular paced rhythm, bundle branch block, pre-excitation syndrome, and left ventricular hypertrophy. An experienced observer assessed the presence of IBWI qualitatively.
Result: There were a total of 84 patients. The mean age was 65±15 years. Fifty-seven were male (68%), 39(46%) had resting perfusion defects in the inferobasal wall and 45(54%) had normal perfusion (NP) studies. The most common indication for the stress test was evaluation for presence of coronary artery disease.
The R/S ratio in lead V1 is < 1 in 100% and 98% of patients with and without IBWI, respectively. Among patients with NP, the mean R/S ratio in lead V1 was 0.09±0.36 as compared to 0.18±0.39 among patients with IBWI (p=NS). The mean R/S ratio in lead V2 was 0.72±0.85 in patients with NP and 0.69±0.86 for patients with IBWI (p=NS). In addition, R wave duration in lead V1 were same in both groups (0.02±0.01 msec, p=NS). The R wave durations in lead V2 were 0.034±0.014 msec and 0.032±0.012 msec in patients with and without IBWI, p=NS. Compared to patients with NP, majority of patients with IBWI had upright T wave in V1 (74% vs. 31%, p<0.001) and V2 (97% vs. 76%, p=0.004).
Sensitivity and Specificity of ECG Criteria for the Diagnosis of IBWI
Sensitivity / Specificity
V1 R/S ³1 0 / 97%
V2 R/S ³1 26% / 74%
V1 R duration ³0.04 msec 31% / 64%
V2 R duration ³0.04 msec 59% / 36%
V1 T wave upright 74% / 69%
V2 T wave upright 97% / 24%
Conclusion: Based on our data, the established ECG criteria of V1 or V2 R/S ratio > 1 or R wave duration in lead V1 or V2 has low sensitivity for the diagnosis of IBWI. However, the presence of an upright T wave in V1 is the best ECG criterion for the diagnosis of IBWI.