Heart rate in ambulatory heart failure ouptatients followed in multidisciplinary heart failure clinics

Abstract:

Background: Persistent resting heart rates are known to increase the risk of tachycardia induced cardiomyopathy. Recent clinical studies have identified that improved rate control may improve clinical outcomes in heart failure (HF) patients. We examined a large cohort of ambulatory outpatients, with a confimred diagnosis of chronic HF and referred to a clinic in the Canadian Heart Failure Network (CHFN). We must report the range of resting heart rates in patients seen at their first visit and one year visit in specialized HF outpatient clinics where follow-up is more structured but representative of a broad of HF Clinics.
Results: 17,790 HF patients had resting heart rate recorded at their first clinic visit between Jan 1999 to Oct 2010. Duration of HF was 0-5 yrs in 84.7%, 6-10 yrs in 9.3%, and >10 yrs in 6.0%. Etiology of HF was ischemic in 38.8%, non-ischemic in 53.0%, and other in 8.2%. Median age was 66.0 yrs. 69% of the population were male. Beta-blocker use in ischemic and non-ischemic patients was 74.6%. Atrial fibrillation was present in 25.0%. As a limiting symptom, dyspnea was the most common and increased with higher HR's while fatigue increased with lower HR's (p>0.001). 3,214 patients also had a recorded resting HR at 1 yr. Of these, 29.2% had a 1 yr resting HR >80bpm and 5.4% had a resting HR >100bpm.
Conclusions/l In a broad population of HF patients referred to specialized outpatient HF clinics, resting heart rates are above 80bpm in almost 30% of patients at 1 yr. While the data do not identify whether this is a cause or consequence of symptoms or the disease process, more aggressive heart rate control may be required based on positive results from recent prospective clinical studies.