Abstract 15688: Electrocardiographic Patterns Differentiating "Apical Ballooning" From Anterior Myocardial Infarction

Abstract

Introduction: Left ventricular apical ballooning (AB) mimics anterior myocardial infarction (AMI). This study assessed if the ECG can differentiate between these two syndromes with a similar clinical presentation. Methods: Among 2086 patients (pts) with an ACS, 33 (1.6%) with AB were identified (29 f, 4 m, median age 77 years) and compared to 28 consecutive age and sex matched AMI pts undergoing PCI of the LAD with similar findings on LV angiography. Results: AB pts arrived at the hospital later after symptom onset (median 21 vs 5 hours; p<0.001). On the admission ECG, the number of leads with ST-segment elevation (4 [3-6] vs 5 [5-7], p=0.005) and the magnitude of ST-segment elevation (0.7 [0.5-0.9] vs 0.9 [0.7-1.5] mV, p=0.002) were greater in AMI. Reciprocal ST-segment depression was similar (27% vs 54%, p=ns). A positive T wave in aVR was more frequent in AB (49% vs 7%, p<0.001). During follow-up, AB pts had more leads with T-wave inversion (8 [8-9] vs 6 [5-8], p<0.001) and a larger magnitude of T-wave inversion (2.9 [2.2-4.6] vs 1.4 [0.9-2.3] mV, p<0.001). T-wave inversion was similar in I, aVL and V2-V5. AB pts, however, showed negative T-waves also in lead II (74% vs 22%, p<0.001), III (34% vs 4%, p=0.004), aVF (51% vs 11%, p=0.001) and a positive T wave in aVR (100% vs 70%, p=0.005). The QTc interval was longer in AB (515 [482-543] vs 458 [435-484] ms, p<0.001). An abnormal Q wave on admission was more frequent in AMI (21% vs 79%, p<0.001) and persisted but was absent in AB at discharge (0% vs 61%, p<0.001). Ventricular tachycardia was similar (2% vs 14%, p=ns) but atrial fibrillation occurred only in AB (21% vs 0%, p=0.013). The ECG normalized in all AB but in only 1 AMI pt (p<0.001). Overall, despite a similar ejection fraction (54±15 vs 55±13 %) and lower troponin I values (7.5±6.9 vs 238±221 ng/ml, p<0.001), AB pts developed significantly more adverse events compared to AMI pts (52% vs 18%, p<0.008). Conclusion: ECG patterns in AB are significantly different from those in AMI. On admission, the extent of ST-segment elevation and the number of Q waves are greater in AMI. During follow-up, no Q wave, a longer QTc interval, a greater extent of T-wave inversion and a positive T wave in aVR are typical findings in AB. Adverse events are more frequent in AB than in AMI.