[Electrocardiographic changes in patients presenting with an acute coronary syndrome: "apical ballooning" versus anterior myocardial infarction].

BACKGROUND AND OBJECTIVE: Transient left ventricular (LV) apical ballooning (AB) is characterized by chest pain, electrocardiographic (ECG) changes and LV apical akinesia mimicking anterior myocardial infarction (AMI) in the absence of coronary artery disease. This study aimed to assess if the ECG could reliably differentiate between these two syndromes with a similar clinical presentation.

PATIENTS AND METHODS: Among 2086 patients with an acute coronary syndrome (ACS) undergoing coronary angiography over a 6.5-year period, 33 patients (1.6 %) with apical ballooning (AB) were identified (29 f, 4 m, median age 77 [68 - 80] years). AB patients were compared to 28 consecutive age and sex matched AMI patients (23 f, 5 m; 68 [56 - 76] years) undergoing successful PCI of the LAD with similar findings on LV angiography. We compared the ECG on admission, at the time of maximal T-wave inversion, before discharge and the longest QTc-interval.

RESULTS: The number of leads showing ST-segment elevation (4 [3 - 6] vs. 5 [5 - 7]; p = 0,005) and the sum of the level of ST-segment elevation (0,7 [0,5 - 0,9] mV vs. 0,9 [0,7 - 1,5] mV; p = 0,002) was significantly greater in AMI. An abnormal Q wave at presentation was more frequent in AMI (21 % vs 79 %, p < 0.001) and persisted in half of AMI patients whereas the Q wave disappeared in all AB patients during follow-up (0 % vs. 61 %, p < 0.001). The QTc interval was significantly longer in AB (568 [521 - 614] ms vs. 471 [438 - 513] ms; p < 0,001). During follow-up, AB patients displayed significantly more leads with T-wave inversion (8 [8 - 9] vs. 6 [5 - 8]; p < 0,001), and the sum of the level of T-wave inversion (2,9 [2,2 - 4,6] mV vs. 1,4 [0,9 - 2,3] mV; p < 0,001) was significantly larger than in AMI. A formula considering ST-segment elevation on admission and T-wave inversion as well as Q waves during follow-up allowed discrimination between AB and AMI (sensitivity 93 %, specificity 86 %).

CONCLUSION: ECG findings in AB patients are significantly different from those in AMI patients. At initial presentation, the extent of ST-segment elevation and the number of abnormal Q waves are greater in AMI. During follow-up, no Q wave, a longer QTc interval and a greater extent of T-wave inversion are typical findings in AB patients.