1.
Resting heart rate and risk of incident heart failure: three prospective cohort studies and a systematic meta-analysis.
Khan, H, Kunutsor, S, Kalogeropoulos, AP, Georgiopoulou, VV, Newman, AB, Harris, TB, Bibbins-Domingo, K, Kauhanen, J, Gheorghiade, M, Fonarow, GC, et al
Journal of the American Heart Association. 2015;(1):e001364
Abstract
BACKGROUND The relationship between resting heart rate (RHR) and incident heart failure (HF) has been questioned. METHODS AND RESULTS RHR was assessed at baseline in 7073 participants in 3 prospective cohorts (Cardiovascular Health Study, Health ABC study and Kuopio Ischemic Heart Disease Study) that recorded 1189 incident HF outcomes during 92 702 person-years of follow-up. Mean age of participants was 67 (9.9) years and mean RHR was 64.6 (11.1) bpm. Baseline RHR correlated (P<0.001) positively with body mass index (r=0.10), fasting glucose (r=0.18), and C-reactive protein (r=0.20); and inversely with serum creatinine (r=-0.05) and albumin (r=-0.05). Baseline RHR was non-linearly associated with HF risk. The age and sex-adjusted hazard ratio for HF comparing the top (>72 bpm) versus the bottom (<57 bpm) quartile of baseline RHR was 1.48 (95% confidence interval [CI] 1.26 to 1.74) and was modestly attenuated (1.30, 95% CI 1.10 to 1.53) with further adjustment for body mass index, history of diabetes, hypertension, smoking status, serum creatinine, and left ventricular hypertrophy. These findings remained consistent in analyses accounting for incident coronary heart disease, excluding individuals with prior cardiovascular events, or those taking beta-blockers; and in subgroups defined by several individual participant characteristics. In a pooled random effects meta-analysis of 7 population-based studies (43 051 participants and 3476 HF events), the overall hazard ratio comparing top versus bottom fourth of RHR was 1.40 (95% CI: 1.19 to 1.64). CONCLUSIONS There is a non-linear association between RHR and incident HF. Further research is needed to understand the physiologic foundations of this association.
2.
Heart rate-lowering and -regulating effects of once-daily sustained-release diltiazem.
Boden, WE, Vray, M, Eschwege, E, Lauret, D, Scheldewaert, R
Clinical cardiology. 2001;(1):73-9
Abstract
BACKGROUND Epidemiologic evidence suggests that an elevated heart rate (HR) is an adverse and independent prognostic factor in arterial hypertension and other cardiovascular diseases. Although diltiazem is characterized as an HR-lowering calcium antagonist, no studies have quantified the magnitude of HR changes in patients with angina or hypertension. HYPOTHESIS The study was undertaken to explore the magnitude of proportional HR reduction at varying levels of resting HR with the sustained-release formulation of diltiazem (SR diltiazem) at the usual clinical doses of 200 or 300 mg once daily. METHODS This meta-analysis was conducted on six comparative double-blind studies including 771 patients with angina or hypertension in which SR diltiazem 200-300 mg once daily was compared either with placebo or with other agents known not to influence HR (angiotensin-converting enzyme inhibitors, diuretics). Sustained-release diltiazem decreases elevated baseline HR, with an increasing effect at higher initial rates. RESULTS Multiple comparisons by baseline HR category showed a significant difference between both groups for baseline HR of 74-84 beats/min and > or = 85 beats/min (p = 0.001). Sustained-release diltiazem had no significant HR-decreasing effect on baseline HR < or =74 beats/min but appears to have a genuine regulating effect on HR: it reduces tachycardia without inducing excessive bradycardia. These findings are in contrast to those with dihydropyridine calcium antagonists, which tend to increase HR and have been associated with an adverse outcome in acute cardiovascular conditions. At the same time, there is evidence to suggest that HR-lowering calcium-channel blockers decrease cardiovascular event rates following myocardial infarction. CONCLUSION When calcium antagonists are indicated for use in patients with angina or hypertension, an HR-lowering agent, that is, diltiazem rather than dihydropyridine, should be recommended.