Does peak oxygen pulse complement peak oxygen uptake in risk stratifying patients with heart failure?

Area of Science:

• Cardiology
• Exercise Physiology

Background:

• Limited data exists on the prognostic value of peak exercise oxygen pulse (peak O(2) pulse) in heart failure (HF).
• Peak O(2) pulse serves as a surrogate marker for stroke volume during exercise.

Purpose of the Study:

• To evaluate the prognostic utility of peak O(2) pulse and peak oxygen uptake (VO(2)) in predicting cardiac events in HF patients.
• To establish optimal cut-off points for these parameters to stratify risk.

Main Methods:

• Analysis of cardiopulmonary exercise testing data from 998 HF patients (May 1994 - November 2007).
• Peak O(2) pulse calculated as peak VO(2) divided by heart rate, expressed in mL/beat and % of age-predicted value.
• Cox regression analyses and receiver-operating characteristic curves used to assess predictive capabilities and establish cut-off points.

Main Results:

• Both peak VO(2) and age-predicted peak O(2) pulse were independent predictors of mortality (p <0.001).
• Abnormalities in both parameters significantly increased the risk of mortality (4.8-fold) and cardiac events (6.7-fold).
• Age-predicted peak O(2) pulse predicted mortality even in patients with intermediate peak VO(2) levels.

Conclusions:

• Age-predicted peak O(2) pulse is a robust and independent predictor of cardiac mortality in HF.
• This parameter complements peak VO(2) in risk stratification for HF patients.
• Findings highlight the prognostic significance of stroke volume surrogates during exercise in HF management.