Association between early Q-waves and microvascular injury in patients with ST-elevation myocardial infarction and primary percutaneous coronary intervention

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background Pathological early Q-waves (QW) are associated with adverse outcomes in patients with ST-segment elevation myocardial infarction (STEMI). It is still not clear how admission Q-waves are related to microvascular injury (microvascular obstruction (MVO) and intramyocardial haemorrhage (IMH)) observed by cardiovascular magnetic resonance (CMR) after primary percutaneous coronary intervention (pPCI) for STEMI. Aim to determine the association between admission Q-waves and microvascular injury in STEMI patients treated with primary PCI. Methods This prospective study included 98 STEMI patients who underwent pPCI within 12 hours and had no contraindication of CMR investigation. Admission 12-lead electrocardiography was evaluated for the presence of pathological QW, defined as a depth of >0,1 mV and a QW duration of > 30 ms. The patients underwent a cardiac magnetic resonance imaging scan at 6 (interquartile range [IQR]: 5-7) days after pPCI to determine infarct characteristics including MVO (late gadolinium enhancement) and IMH (T2* mapping). Results The 98 first-attack STEMI patients included 87 men and 11 women with a mean age of 55,6 ± 9,7 years in this study. Early QW was observed in 23 (23,5%) patients. These patients were more frequent smokers (p = 0,041), had a significantly more frequent left anterior descending artery as culprit lesion (p = 0,03), and had higher rates of pre-interventional TIMI flow 0 (p = 0,001). Patients with QW was related to larger infarct size (21% vs. 8% of left ventricular mass, p = 0,002), lower ejection fraction (44% vs. 51%, p = 0,004), and larger MVO (53% vs. 32%, p = 0,001) and IMH (34% vs. 17%, p = 0,003). Q-waves remained associated with both MVO (odds ratio: 5,13, 95% confidence interval: 1,98 to 11,2, p < 0,001) and IMH (odds ratio: 3,66, 95% confidence interval: 1,06 to 7,21, p < 0,001) after adjusting for potential confounders (total ischemia time, ST-segment elevation, pre-interventional TIMI flow 0). Conclusions Admission Q-waves in the ECG were as independent early markers of microvascular obstruction and intramyocardial haemorrhage in STEMI patients undergoing pPCI.