Influenza della cardiomegalia sullo stato anatomico e funzionale del polmone nello scompenso cardiaco cronico

Heart and lungs might compete for the intrathoracic space in case of heart enlargement (as in heart failure). Therefore, the pulmonary abnormalities observed in patients with chronic heart failure (restrictive pattern and reduction of diffusion capacity) might be at least in part related to cardiomegaly. In 53 patients (11 women, 42 men, mean age 65 +/- 8 years) with stable heart failure and cardiac enlargement (cardiothoracic ratio-Ctr > or = 50%) we measured carbon monoxide lung diffusion (DLCO), lung tissue content (VT, single breath, expiratory regression of acetylene), alveolar volume (Va, single breath, expiratory regression of methane) and vital capacity (VC). In 16 patients the two subcomponents of DLCO, i.e. alveolar-capillary membrane diffusion (Dm) and diffusion related to capillary volume (Cv), were analyzed. Patients were grouped for Ctr (> or = 60%, Group 1, n = 28 and < 60%, Group 2, n = 25): VT (Group 1 0.62 +/- 0.2 l; Group 2 0.76 +/- 0.2 l, p < 0.01); Va (Group 1 4.21 +/- 0.97 l; Group 2 5.37 +/- 1.12 l, p < 0.0001); VC (Group 1 2.3 +/- 0.6 l; Group 2 3.1 +/- 0.6 l, p < 0.0001); DLCO (Group 1 16.15 +/- 3.95 ml/min x mmHg; Group 2 22.24 +/- 6.57 ml/min x mmHg, p < 0.0001). An inverse correlation was observed between Dm and Ctr (r = -0.47, p < 0.02), which disappeared when Va was accounted for Dm/Va (r = -0.12, NS). Cv was lower in Group 1 vs Group 2. In conclusion, in patients with Ctr > or = 60% (Group 1) "anatomy" (VT, Va, VC and Cv) and function (DLCO) of the lungs are impeded. This is likely due to reduction of space available for the lungs in the thorax by an enlarged heart (no correlation between Dm/Va vs Ctr).