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.)

The correlates of RV dysfunction differ in HFrEF compared with HFpEF and HFmrEF patients. Regardless of the extent of LV dysfunction, the TAPSE/PASP ratio is a powerful independent predictor of prognosis in all heart failure patients.

In patients with CHF, reversible AF and reduction of left atrial contribution to left ventricular filling predict the subsequent development of chronic AF. The onset of AF is associated with clinical and hemodynamic deterioration and may predispose to systemic thromboembolism and poorer prognosis.

In patients with chronic heart failure, MFVPs provide independent prognostic information. Their prognostic value can be further increased by assessment of the changes induced in them by loading manipulations.