Inspiratory capacity (IC) can determine exercise capacity in patients with lung diseases. In this study, we investigated the role of IC in the exercise capacity of patients with cardiac diseases.
Twenty patients (4 female, age range 29-79 years, BMI range 16-30 kg/m2) with primary dilated cardiomyopathy (NYHA class range 1-3; mean±SD ejection fraction: 32%±11) performed spirometry and lung volumes measurement. Patients carried out exercise testing using bicycle ergometry with ramp protocol (work rate increments range 5-15 W/min). Gas exchange and ventilation were measured breath by breath.
Mean(SD) values of IC, FEV1, FEV1/VC, and TLC were 2.88L(0.7), 93%pred(16), 76%(6), and 96%pred(15), respectively. At peak of exercise, mean(SD) values of V’O2, HR and Work Load were 1.39L(0.53), 137bpm(27), and 115watts(59). IC was related to NYHA class (rs=−0.49, p<0.05), V’O2 (r=0.75, p<0.01), and Work Load (r=0.79, p<0.01). Moreover, IC was chosen by multiple regression analysis, as the main predictor variable for V’O2 (r2 = 0.56).CONCLUSIONS AND CLINICAL IMPLICATIONS: In patients with primary dilated cardiomyopathy, resting inspiratory capacity is strictly related to exercise capacity and predicts the oxygen uptake at peak of exercise. Our data suggest that inspiratory capacity can be used in the clinical assessment of primary dilated cardiomyopathy.
A. Chetta, None.