European Heart Journal Advance Access published online on September 30, 2009
European Heart Journal, doi:10.1093/eurheartj/ehp397
The association of admission heart rate and in-hospital cardiovascular events in patients with non-ST-segment elevation acute coronary syndromes: results from 135 164 patients in the CRUSADE quality improvement initiative
1 Brigham and Women's Hospital, Boston, MA, USA
2 Division of Cardiology, Department of Medicine, St Luke's Roosevelt Hospital, Columbia University College of Physicians and Surgeons, St Luke's-Roosevelt Hospital Center, 1000 Amsterdam Avenue, New York, NY 10019, USA
3 Duke Clinical Research Institute, Duke University Medical Center, Durham, NC, USA
Received 12 January 2009; revised 17 July 2009; accepted 8 September 2009 * Corresponding author. Tel: +1 212 523 7373, Email: fmesserl{at}chpnet.org
Aims: To evaluate the relationship between presenting heart rate (HR) and in-hospital events in patients with non-ST-segment elevation acute coronary syndromes (NSTE-ACS).
Methods and results: We evaluated 139 194 patients with NSTE-ACS in the CRUSADE quality improvement initiative. The presenting HR was summarized as 10 beat increments. Patients with systolic BP < 90 mm Hg (4030 patients) were excluded to avoid the confounding effect of cardiogenic shock. An adjusted odds ratio (OR) was calculated using a reference OR = 1 for HR of 60–69 b.p.m. after controlling for baseline variables. Primary outcome was a composite of in-hospital events all-cause mortality, non-fatal re-infarction, and stroke. Secondary outcomes were each of these considered separately. From the cohort of 135 164 patients, 8819 (6.52%) patients had a primary outcome (death/re-infarction or stroke) of which 5271 (3.90%) patients died, 3578 (2.65%) patients had re-infarction, and 1038 (0.77%) patients had a stroke during hospitalization. The relationship between presenting HR and primary outcome, all-cause mortality, and stroke followed a ‘J-shaped’ curve with an increased event rate at very low and high HR even after controlling for baseline variables. However, there was no relationship between presenting HR and risk of re-infarction.
Conclusion: In contrast to patients with stable CAD, in the acute setting, the relationship between presenting HR and in-hospital cardiovascular outcomes has a ‘J-shaped’ curve (higher event rates at very low and high HRs). These associations should be considered in ACS prognostic models.
Key Words: Cardiovascular events • Heart rate • J-curve