Electrocardiographic (ECG) predictors of major adverse cardiac events in women with ischemia and no obstructive coronary artery disease (INOCA)

Abstract Introduction The Women's Ischemia Syndrome Evaluation (WISE) studies observed that majority of women undergoing coronary angiography for symptoms/signs of ischemia have no obstructive coronary artery disease (INOCA) but have an increased risk of major adverse cardiac events (MACE) exceeding 2.5% yearly by 5 years. Identifying modifiable and non-modifiable factors that help predict or contribute to adverse outcomes in this population is important. Purpose Identifying electrocardiographic predictors of MACE in women with INOCA. Methods In a cohort of women referred for coronary angiography between 1996–2001 for symptoms and/or signs of ischemia, 944 underwent a resting 12-lead ECG at baseline read at core lab. No obstructive CAD was found in 567/944 (60%), (mean age 55.6±11 years). Complete follow up information for MACE as (first occurrence of all-cause death, nonfatal myocardial infarction (MI), nonfatal stroke, or hospitalization for heart failure) or angina was available in 425 women. Results At follow up (median 5.9 years) MACE had occurred in 17.6% with angina hospitalization in 22.8% of these women. Women who experienced MACE were older (mean age 59±11 vs 55±10 years, P=0.02) and had longer corrected QT interval (mean QTc 437±29.7 vs 425±26.7 ms, P=0.001) vs. women without MACE. Diabetes, hypertension and history of smoking did not differ between MACE groups. Predictors of MACE by univariate analysis were: age at presentation (P=0.013), baseline heart rate (P=0.03), and QTc (P=0.0005). Baseline ST-T wave changes, QTc and waist circumference predicted angina hospitalization (P=0.003, 0.003 and 0.013 respectively). After adjusting for other risk factors in the multivariate analysis (see Figure) QTc, peripheral arterial disease (PAD) and current smoking were found to be independent predictors for MACE. ST-T wave changes and QTc independently predicted angina hospitalizations. Conclusion Among ECG findings in women with INOCA, QTc was a significant predictor of MACE and this was driven by hospitalization with angina. Ongoing ischemia likely contributes to these baseline ECG signals which could prove useful to better select subgroups for more intense anti-ischemic management. Figure 1 Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): National Heart, Lung, and Blood Institute (NHLBI)