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Reduced Sympathetic Reserve Detectable by Heart Rate Response after Dipyridamole in Anginal Patients with Normal
Lauro Cortigiani1, Clara Carpeggiani2, Laura Meola1
1Cardiology Division, San Luca Hospital, 55100 Lucca, Italy.
Insights
Reduced heart rate reserve (HRR) during dipyridamole stress echocardiography (SE) in patients with ischemia and normal coronary arteries (INOCA) predicts worse survival. This finding is independent of inducible ischemia, highlighting HRR as a key prognostic indicator.
Area of Science:
- Cardiology
- Cardiac Physiology
- Diagnostic Imaging
Background:
- Patients with ischemia and normal coronary arteries (INOCA) may exhibit abnormal cardiac sympathetic function.
- This dysfunction can manifest as a reduced heart rate reserve (HRR) during stress testing.
Purpose of the Study:
- To determine if HRR measured during dipyridamole stress echocardiography (SE) can predict patient outcomes.
- To evaluate the prognostic value of HRR in the INOCA population.
Main Methods:
- Dipyridamole SE was conducted on 292 INOCA patients.
- HRR was calculated as peak/rest heart rate, with abnormality defined by specific thresholds.
- All-cause mortality served as the primary endpoint over a median follow-up of 10.4 years.
Main Results:
- Abnormal HRR was observed in 37% of patients.
- The 15-year mortality rate was significantly higher in patients with abnormal HRR (54%) compared to those with normal HRR (27%).
- Blunted HRR independently predicted worse outcomes, surpassing inducible ischemia as a prognostic factor.
Conclusions:
- A reduced HRR during dipyridamole SE is a significant predictor of mortality in INOCA patients.
- HRR provides prognostic information beyond the presence of inducible ischemia.
- HRR assessment during SE is a valuable tool for risk stratification in INOCA.
Abstract:
Background. Patients with ischemia and normal coronary arteries (INOCA) may show abnormal cardiac sympathetic function, which could be unmasked as a reduced heart rate reserve (HRR) during dipyridamole stress echocardiography (SE). Objectives. To assess whether HRR during dipyridamole SE predicts outcome. Methods. Dipyridamole SE was performed in 292 patients with INOCA. HRR was measured as peak/rest heart rate and considered abnormal when ≤1.22 (≤1.17 in presence of permanent atrial fibrillation). All-cause death was the only endpoint. Results. HRR during SE was normal in 183 (63%) and abnormal in 109 patients (37%). During a follow-up of 10.4 ± 5.5 years, 89 patients (30%) died. The 15-year mortality rate was 27% in patients with normal and 54% in those with abnormal HRR (p < 0.0001). In a multivariable analysis, a blunted HRR during SE was an independent predictor of outcome (hazard ratio 1.86, 95% confidence intervals 1.20-2.88; p = 0.006) outperforming inducible ischemia. Conclusions. A blunted HRR during dipyridamole SE predicts a worse survival in INOCA patients, independent of inducible ischemia.
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