Cardiac remodeling is generally accepted as a determinant of the clinical course of heart failure (HF). Defined as genome expression resulting in molecular, cellular and interstitial changes and manifested clinically as changes in size, shape and function of the heart resulting from cardiac load or injury, cardiac remodeling is influenced by hemodynamic load, neurohormonal activation and other factors still under investigation. Although patients with major remodeling demonstrate progressive worsening of cardiac function, slowing or reversing remodeling has only recently become a goal of HF therapy. Mechanisms other than remodeling can also influence the course of heart disease, and disease progression may occur in other ways in the absence of cardiac remodeling. Left ventricular end-diastolic and end-systolic volume and ejection fraction data provide support for the beneficial effects of therapeutic agents such as angiotensin-converting enzyme (ACE) inhibitors and beta-adrenergic blocking agents on the remodeling process. These agents also provide benefits in terms of morbidity and mortality. Although measurement of ejection fraction can reliably guide initiation of treatment in HF, opinions differ regarding the value of ejection fraction data in guiding ongoing therapy. The role of echocardiography or radionuclide imaging in the management and monitoring of HF is as yet unclear. To fully appreciate the potential benefits of HF therapies, clinicians should understand the relationship between remodeling and HF progression. Their patients may then, in turn, acquire an improved understanding of their disease and the treatments they are given.
Aims
The objectives of the present study were to describe epidemiology and outcomes in ambulatory heart failure (HF) patients stratified by left ventricular ejection fraction (LVEF) and to identify predictors for mortality at 1 year in each group.
Methods and results
The European Society of Cardiology Heart Failure Long‐Term Registry is a prospective, observational study collecting epidemiological information and 1‐year follow‐up data in 9134 HF patients. Patients were classified according to baseline LVEF into HF with reduced EF [EF <40% (HFrEF)], mid‐range EF [EF 40–50% (HFmrEF)] and preserved EF [EF >50% (HFpEF)]. In comparison with HFpEF subjects, patients with HFrEF were younger (64 years vs. 69 years), more commonly male (78% vs. 52%), more likely to have an ischaemic aetiology (49% vs. 24%) and left bundle branch block (24% vs. 9%), but less likely to have hypertension (56% vs. 67%) or atrial fibrillation (18% vs. 32%). The HFmrEF group resembled the HFrEF group in some features, including age, gender and ischaemic aetiology, but had less left ventricular and atrial dilation. Mortality at 1 year differed significantly between HFrEF and HFpEF (8.8% vs. 6.3%); HFmrEF patients experienced intermediate rates (7.6%). Age, New York Heart Association (NYHA) class III/IV status and chronic kidney disease predicted mortality in all LVEF groups. Low systolic blood pressure and high heart rate were predictors for mortality in HFrEF and HFmrEF. A lower body mass index was independently associated with mortality in HFrEF and HFpEF patients. Atrial fibrillation predicted mortality in HFpEF patients.
Conclusions
Heart failure patients stratified according to different categories of LVEF represent diverse phenotypes of demography, clinical presentation, aetiology and outcomes at 1 year. Differences in predictors for mortality might improve risk stratification and management goals.
The importance of resting heart rate (HR) as a prognostic factor and potential therapeutic target is not yet generally accepted. Recent large epidemiologic studies have confirmed earlier studies that showed resting HR to be an independent predictor of cardiovascular and all-cause mortality in men and women with and without diagnosed cardiovascular disease. Clinical trial data suggest that HR reduction itself is an important mechanism of benefit of beta-blockers and other heart-rate lowering drugs used after acute myocardial infarction, in chronic heart failure, and in stable angina pectoris. Pathophysiological studies indicate that a relatively high HR has direct detrimental effects on the progression of coronary atherosclerosis, on the occurrence of myocardial ischemia and ventricular arrhythmias, and on left ventricular function. Studies have found a continuous increase in risk with HR above 60 beats/min. Although it may be difficult to define an optimal HR for a given individual, it seems desirable to maintain resting HR substantially below the traditionally defined tachycardia threshold of 90 or 100 beats/min. These findings suggest that the potential role of HR and its modulation should be considered in future cardiovascular guidance documents.
Background-The predictive value of heart rate variability (HRV) in chronic heart failure (CHF) has never been tested in a comprehensive multivariate model using short-term laboratory recordings designed to avoid the confounding effects of respiration and behavioral factors. Methods and Results-A multivariate survival model for the identification of sudden (presumably arrhythmic) death was developed with data from 202 consecutive patients referred between 1991 and 1995 with moderate to severe CHF (age 52Ϯ9 years, left ventricular ejection fraction 24Ϯ7%, New York Heart Association class 2.3Ϯ0.7; the derivation sample). Time-and frequency-domain HRV parameters obtained from an 8Ј recording of ECG at baseline and during controlled breathing (12 to 15 breaths/min) were challenged against clinical and functional parameters. This model was then validated in 242 consecutive patients referred between 1996 and 2001 (validation sample). In the derivation sample, sudden death was independently predicted by a model that included low-frequency power (LFP) of HRV during controlled breathing Յ13 ms 2 and left ventricular end-diastolic diameter Ն77 mm (relative risk [RR] 3.7, 95% CI 1.5 to 9.3, and RR 2.6, 95% CI 1.0 to 6.3, respectively). The derivation model was also a significant predictor in the validation sample (Pϭ0.04). In the validation sample, LFP Յ11 ms 2 during controlled breathing and Ն83 ventricular premature contractions per hour on Holter monitoring were both independent predictors of sudden death (RR 3.0, 95% CI 1.2 to 7.6, and RR 3.7, 95% CI 1.5 to 9.0, respectively).
Conclusions-Reduced short-term LFP during controlled breathing is a powerful predictor of sudden death in patients withCHF that is independent of many other variables. These results refine the identification of patients who may benefit from prophylactic implantation of a cardiac defibrillator. (Circulation. 2003;107:565-570.)
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