The aim of this study was to explore the value of noninvasive predictors of death/mode of death in ambulant outpatients with chronic heart failure (HF).
Background
Mortality in chronic HF remains high, with a significant number of patients dying of progressive disease. Identification of these patients is important.
Methods
We recruited 553 ambulant outpatients age 63 ± 10 years with symptoms of chronic HF (New York Heart Association functional class, 2.3 ± 0.5) and objective evidence of left ventricular dysfunction (ejection fraction <45%, cardiothoracic ratio >0.55, or pulmonary edema on chest radiograph). After 2,365 patient-years of follow-up, 201 patients had died, with 76 events due to progressive HF.
Results
Independent predictors of all-cause mortality assessed with the Cox proportional hazards model were as follows: a low standard deviation of all normal-to-normal RR intervals (SDNN); lower serum sodium and higher creatinine levels; higher cardiothoracic ratio; nonsustained ventricular tachycardia; higher left ventricular end-systolic diameter; left ventricular hypertrophy; and increasing age. Independent predictors of death specific to progressive HF were SDNN, serum sodium and creatinine levels. The hazard ratio of progressive HF death for a 10% decrease in SDNN was 1.06 (95% confidence interval [CI], 1.01 to 1.12); for a 2 mmol/l decrease in serum sodium, 1.22 (95% CI, 1.08 to 1.38); and for a 10 μmol/l increase in serum creatinine, 1.14 (95% CI, 1.09 to 1.19) (all p < 0.01).
Conclusions
In ambulant outpatients with chronic HF, low serum sodium and SDNN and high serum creatinine identify patients at increased risk of death due to progressive HF.
Abbreviations
ACE
angiotensin-converting enzyme
CI
confidence interval
EF
ejection fraction
eGFR
estimated glomerular filtration rate
HF
heart failure
HFP
high-frequency power
HR
hazards ratio
HRV
heart rate variability
LFP
low-frequency power
NYHA
New York Heart Association
ROC
receiver operating characteristic
SDNN
standard deviation of all normal-to-normal RR intervals
TP
total power
UK-HEART
United Kingdom Heart failure Evaluation and Assessment of Risk Trial
Financial support for this study was by the Chest, Heart, and Stroke Association (Scotland) and the Northern and Yorkshire Research and Development Directorate. Drs. Kearney, Fox, and Shah are supported by the British Heart Foundation.