Oral Presentation No. 69
Chronotropic incompetence: still a suitable indicator?

Chronotropic incompetence (CI) is defined as the inability to increase heart rate (HR) in response to increased activity. It is common in patients (pts) with cardiovascular (CV) disease, being a predictor of major adverse CV events; however, its importance is often underestimated in clinical practice.

Evaluate the prognostic value of CI in pts with known coronary artery disease (CAD) who performed Bruce protocol treadmill testing.

Unicentric, retrospective analysis of consecutive pts with known CAD who underwent Bruce protocol treadmill testing between 2009 and 2010. Chronotropic index (ChI) was calculated as:(peak HR–resting HR)/(220–age–resting HR). CI was defined as ChI < 80% (< 62% in pts prescribed with beta-blockers). Pts were divided in two groups-G1: CI and G2: normal chronotropic response. Events were defined as: de novo heart failure (HF), CAD progression, myocardial infarction (MI), stroke, all-cause mortality and CV mortality.

A total of 471 pts were included (87.3% male, mean age 69 ± 9.8 years). Mean follow-up was 9.7 years. The groups were similar regarding sex, age, body mass index, diabetes, arterial hypertension, dyslipidemia, MI and left ventricle ejection fraction (P > 0.050). CI was identified in 27.4% pts. Comparing G1 vs. G2, no differences were found related to all-cause mortality, de novo HF, CAD progression, MI and stroke (P > 0.050). However, statistically significant differences were found regarding CV mortality (P = 0.028).

CI is a simple an easily available parameter that shows a clear association with CV mortality in a long-term follow-up of pts with CAD.