Ischemic Versus Non-Ischemic (Neurogenic) Myocardial Contractility Impairment in Acute Coronary Syndromes: Prevalence and Impact on Left Ventricular Systolic Function Recovery

BACKGROUND: Neurogenic mechanism is believed to contribute to left ventricular (LV) systolic dysfunction in acute coronary syndromes (ACS); its extreme form is known as takotsubo cardiomyopathy. However, the magnitude of neurogenic contribution to LV dysfunction in all-comer first-time ACS remains unknown. MATERIAL/METHODS: In 120 consecutive patients with first-time ACS (age 66.3±12.3years, 40 women) coronary angiograms were individually matched to the echocardiographic left ventricular (LV) segments (17-segment model). Baseline contractility impairment was classified as ischemic (I): confined to the stenotic artery(ies) supply area(s), neurogenic (N): in absence of attributable coronary stenosis, or partially ischemic/partially neurogenic (I&N). Echocardiography was repeated at 6 months to determine LV systolic function recovery. RESULTS: Neurogenic component (NC) contribution to myocardial contractility impairment was present in 24.2% of ACS patients, with pure N in 6.7% and I&N in 17.5%. Diabetes/pre-diabetes was present in 38.5% vs. 33.5% vs. 0% (I vs. I&N vs. N; p=0.02). Major stressor preceding symptom onset was reported in 3.3% in I, 9.5% in I&N, and 25.0% in N (p=0.03). The number of LV segments with contractility impairment was 2±4 in I, 17±11 in I&N, and 3±16 in N (p<0.05). NC presence was independently associated with better recovery of global LV systolic function (OR 2.99, 95% CI: 1.16–7.76; p=0.024). CONCLUSIONS: Novel findings from this study are: (1) NC may contribute to myocardial contractility impairment in 1 in every 4 first-time ACS patients, (2) NC contribution to contractility impairment in ACS is blunted in diabetes or pre-diabetes, and (3) LV systolic function recovery is better in patients with NC.