Ventilatory inefficiency reflects right ventricular dysfunction in systolic heart failure.

Area of Science:

• Cardiology
• Pulmonary Medicine
• Exercise Physiology

Background:

• Increased minute ventilation (VE)/carbon dioxide production (VCO2) ratio, or ventilatory inefficiency (VI), is linked to poor outcomes in patients with left ventricular systolic dysfunction (LVSD).
• A direct association between VI and specific cardiac abnormalities has not been clearly established.

Purpose of the Study:

• To investigate the relationship between ventilatory inefficiency (VE/VCO2 ratio) and cardiac abnormalities in patients with severe LVSD.
• To determine if VI is a marker for specific cardiac dysfunction in this patient population.

Main Methods:

• Cardiopulmonary exercise test (CPET) data from 83 patients with severe LVSD were analyzed.
• Patients were stratified into two groups based on their VE/VCO2 ratio at the anaerobic threshold (VE/VCO2@AT).
• Clinical, CPET, echocardiographic, and hemodynamic data were compared between groups.

Main Results:

• Patients with higher VE/VCO2@AT exhibited reduced exercise capacity, lower oxygen pulse, and a blunted systolic blood pressure response.
• No significant differences were found in left ventricular size, ejection fraction, or mitral regurgitation between groups.
• Higher VE/VCO2@AT was strongly associated with larger right ventricular dimensions and more severe right ventricular systolic dysfunction, including reduced fractional area change and tricuspid annular plane systolic excursion (TAPSE).
• TAPSE and pulmonary artery systolic pressure were independently associated with VE/VCO2@AT and VE/VCO2 slope.

Conclusions:

• Ventilatory inefficiency (VI) serves as a functional, noninvasive marker of advanced right-sided heart dysfunction in patients with severe LVSD.
• VI and TAPSE demonstrated similar predictive value for mortality or need for transplant, underscoring the clinical significance of right ventricular function assessment.