Sviazova, Natalia

Abstract Aims Chronotropic incompetence (CI) is a biomarker of cardiac autonomic dysfunction. The aim of the study is to assess the risk stratification value of CI during exercise or pharmacological stress echocardiography in patients with chronic coronary syndromes. Methods and results In a prospective, multicenter, international, observational study, we enrolled 13 445 patients with known or suspected chronic coronary syndromes who underwent stress echocardiography in 19 clinical sites from 10 countries using either exercise (n = 2594), dobutamine (n = 2440), or dipyridamole (n = 8411). Heart rate was automatically measured from the 1-lead ECG in the echocardiography monitor. We considered CI as failure to reach 85% of the maximal predicted (220-age) heart rate for exercise and dobutamine, and heart rate reserve (peak/rest heart rate) ≤ 1.22 (≤1.17 if in permanent atrial fibrillation) for dipyridamole stress. The primary outcome was all-cause death. CI was observed in 5045 patients (38%) and stress-induced regional wall motion abnormalities in 1648 (13%). Over a median follow-up time of 3.4 years (interquartile range, 1.6–9.1 years), there were 2426 (18%) deaths. The 10-year mortality was 39% in patients with and 21% in patients without CI (P < 0.0001). CI was associated with a significant increase in 10-year mortality in all age groups ranging from ≤54 years to ≥75 years (P < 0.0001). In addition, it was associated with increased mortality (P < 0.0001) irrespective of β-blocker use. Cox multivariable analysis revealed that CI was an independent predictor of mortality (HR: 1.60, 95% confidence interval: 1.47–1.74; P < 0.0001) together with age, male sex, diabetes mellitus, left ventricular ejection fraction, and resting heart rate. Conclusion In patients with chronic coronary syndromes, CI during exercise or pharmacological stress is a simple and objective predictor of survival.

Over the past decade, stress echocardiography has evolved from a test for assessing epicardial artery stenosis to a comprehensive functional test, targeting multiple cardiovascular parameters. The new approach includes several structured steps: (a) evaluating regional wall motion abnormalities to detect epicardial artery stenosis or vasospasm; (b) assessing pulmonary congestion and diastolic function via B-lines with lung ultrasound; (c) gauging preload and contractile reserve with volumetric echocardiography; (d) measuring coronary microvascular reserve using Doppler-based coronary flow velocity in the middistal left anterior descending artery; and (e) determining cardiac sympathetic reserve by tracking heart rate reserve on an ECG. This evolution was supported extensively by the Italian Society of Echocardiography and Cardiovascular Imaging (SIECVI), which played a key role in five areas: (1) developing the initial, curiosity-driven project; (2) disseminating protocols and results at national and international conferences, supporting logistic infrastructure and publication expenses; (3) establishing a digital platform (customized Redcap) for data entry and storage; (4) facilitating patient recruitment across 19 Italian centers; and (5) offering formal endorsement through six presidencies, adding credibility and reach beyond any single institution. The protocol quickly advanced from concept to high-impact publications, earning inclusion in 2024 specialty guidelines. Initially Italian-led, the study now includes 50 centers across 20 countries (e.g. USA and China). Beyond the 50 peer-reviewed papers published in 2016–2024, this study offers a novel, sustainable approach to cardiac stress testing, providing more information at lower costs, with zero radiation and minimal environmental impact. SIECVI’s endorsement was instrumental in amplifying the study’s rigor and outreach.