Clinical and Prognostic Value of the Electrocardiogram in Patients With Acute Occlusion of the Left Circumflex Coronary Artery

Abstract

The utility of the electrocardiogram (ECG) in patients with acute left circumflex (LC) coronary occlusion is not established. This study aimed at determining the clinical, angiographic, and prognostic characteristics associated with the different patterns of ST-segment changes in patients with LC occlusion. A cohort of 314 patients with LC occlusion was categorized according to the admission ECG: (1) ST-segment elevation (ST-E, n=208), (2) isolated ST-segment depression in precordial leads (ST-D, n=62), and (3) negligible ST-segment changes (No-ST, n=44). Clinical variables, coronary angiography, and 30-day major adverse cardiac event (MACE) (in-hospital ventricular fibrillation, 1-month mortality, or heart failure) were compared among the three groups. As compared with No-ST, patients with ST-E or ST-D presented more advanced Killip class, higher troponin peak, lower LV ejection fraction, and were independently associated with MACE (odds ratio 5.43, 95% confidence interval 1.09 to 27.20 and odds ratio 3.39, 95% confidence interval 0.66 to 17.50, respectively). Patients with ST-D were tardily reperfused, had more often mitral regurgitation (23.1% vs 9.3% in ST-E and 3.3% in No-ST, p=0.03), and presented ST-segment elevation in leads V7 to V9 in 12 of 16 cases with available recordings. Culprit proximal LC predominated in ST-D (41.9%), distal LC in ST-E (42.8%), and obtuse marginal in No-ST (59.1%) (all p<0.01). The No-ST had smaller coronary vessels and more collaterals. In conclusion, the three ST-segment patterns of LC occlusion identify patients with different clinical, angiographic, and prognostic characteristics. Patients with ST-depression pattern require a prompt reperfusion therapy and could be better recognized by recording leads V7 to V9.

Influence of Left Bundle Branch Block on the Electrocardiographic Changes Induced by Acute Coronary Artery Occlusion of Distinct Location and Duration

“…A practical recommendation derived from our study is the pertinence to routinely record the posterior thoracic leads V7 to V9 in patients with acute coronary syndromes based on the high diagnostic yielding of these leads in cases of LCX occlusion. In a series of patients with LCX occlusion (Vives-Borrás et al, 2017) we have found that leads V7 to V9 depict ST segment elevation even in cases showing only a ST segment depression pattern in the whole ECG. In the swine model we have also confirmed that in contrast to LAD or RCA, the LCX occlusion was the only one depicting ST segment elevation in leads V6 to V9 (Vives-Borrás et al, 2018).…”

Acute Left Circumflex Coronary Artery Occlusion ― Diagnostic Problems of Initial Electrocardiographic Changes ―

“…This result is consistent with a previous study of 314 patients with LCX occlusion, in which proximal LCX occlusion was most frequently observed in patients with ST-segment depression, whereas the distal LCX occlusion was often the culprit artery in the ST-segment elevation group. 11 It is conceivable that the size and location of the culprit artery, the presence of coronary collaterals, and the size of the perfusion territory may play a role in the genesis of the different ST-segment patterns in patients with acute LCX occlusion. Therefore, the precordial ST-segment depression pattern should be interpreted with caution, because these patients appear to have large infarct sizes caused by proximal LCX occlusion, resulting in more advanced acute heart failure.…”

“…This result is consistent with a previous study of 314 patients with LCX occlusion, in which proximal LCX occlusion was most frequently observed in patients with ST-segment depression, whereas the distal LCX occlusion was often the culprit artery in the ST-segment elevation group. 11 It is conceivable that the size and location of the for the identification of regional left ventricular wall motion abnormality before coronary angiography. Posterior left ventricular asynergy was identified in 31 (66%), 38 (81%), and 22 (88%) in the No-ST, ST-E, and ST-D groups, respectively (P=0.07).…”