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Data from: Low chronotropic response in post-myocardial infarction exercise test predicts worse prognosis in patients with preserved or mildly reduced left ventricular ejection fraction

Smarz, Krzysztof1; Tysarowski, Maciej2; Zioło, Jerzy1; Zaborska, Beata1; Jaxa-Chamiec, Tomasz1; Budaj, Andrzej1

Forthcoming on Dryad. https://doi.org/10.5061/dryad.h9w0vt4sk

Data files

This dataset is embargoed . Please contact Krzysztof Smarz at moc.liamtoh@zramsfotzsyzrk with any questions.

Lists of files and downloads will become available to the public when released.

Abstract

Background: Chronotropic incompetence is common in post-myocardial infarction (MI) patients and is associated with reduced exercise capacity. However, its prognostic significance and the determination of threshold values for prognosis remain unclear.

Methods: We assessed 96 post-MI patients with LVEF ≥ 40% at 4 weeks post-event. Patients underwent combined exercise stress echocardiography and cardiopulmonary exercise testing (CPET-SE). The chronotropic response was measured as a percent of the maximal predicted heart rate at peak exercise (%MPHR). Eighty-six patients completed follow-up (median duration: 4.0 years [IQR 2, 5.6]). The primary endpoint was a composite of all-cause mortality or unplanned hospitalization for coronary syndromes or heart failure exacerbation. 

Results: Median age was 60 years (IQR 53, 65), 67% of patients were male, 86% were on beta-blockers, the median LVEF was 57% (IQR 51, 62), and the median peak VO2 was 19 mL/kg/min (IQR 15, 22). Fifteen composite endpoint events occurred, including 3 deaths. A %MPHR threshold of 67% best predicted the primary endpoint (AUC 73%, PPV 29%, NPV 95%, sensitivity 87%, specificity 55%). The primary endpoint occurrence differed significantly between patients below and above this threshold (p = 0.002). In the multivariate Cox regression analysis, %MPHR (HR 0.95, 95% CI 0.92-0.98) and smoking history (HR 2.8, 95% CI 1.1-7.4) correlated with the primary endpoint. 

Conclusions: A chronotropic response below 67% of the maximal predicted heart rate is a negative prognostic marker in post-MI patients with preserved or mildly reduced LVEF. This threshold may help risk-stratify and guide management in this population.