Impact of prolonged elevated heart rate on incidence of major cardiac events in critically ill patients with a high risk of cardiac complications

Objective: To assess the incidence of major cardiac events in critically ill patients with a high risk of cardiac complications presenting with an elevated heart rate. Design and Setting: Observational, retrospective study in a 15-bed medical/surgical Intensive Care Unit (ICU) at a university hospital for a period of 12 months. Patients: We studied patients with a high risk of cardiac complications, according to the revised Goldman index, who were treated for at least 36 hrs in the ICU. Patients presenting with prolonged elevated heart rate, defined as a heart rate >95 beats/min for >12 hrs in at least one 24-hr period of their ICU stay, were investigated. Cardiac high-risk patients not developing this criterion served as controls. Major cardiac events, defined as nonfatal myocardial infarction, nonfatal cardiac arrest, and cardiac related death, were the primary outcome measures. Results: From a total of 791 patients, 69 patients were assessed as cardiac high-risk patients. Of 39 patients with prolonged elevated heart rates, 19 (49%) sustained major cardiac events, whereas in the control group of 30 patients, only four patients (13%) had a major cardiac event (p =.002; odds ratio, 6.2). Patients with elevated heart rate had to be treated 4.5 days longer in the ICU (p =.01), whereas the ICU and 30-day post-ICU discharge survival rates did not differ significantly. Conclusions: In this study, we provide evidence for an increased incidence of major cardiac events in critically ill, cardiac high-risk patients with a prolonged elevated heart rate during their ICU stay. In addition, elevated heart rate was associated with a significantly longer ICU stay.