Lung function in COPD is correlated with increased left ventricular wall stress in coincident heart failure
Background: COPD and heart failure exhibit a considerable coincidence. Beside a well-known increased right heart load, dedicated pulmonary interactions with the left ventricle (LV) are less understood and the question remains, whether specific interactions exist beyond common shared risk factors of both diseases.
Methods and Results: LV wall stress was measured by cardiac magnetic resonance imaging in 28 patients with COPD (GOLD I to III) and heart failure (LVEF of 42 ± 19%) due to non-ischemic (19 patients) and ischemic cardiomyopathy (9 patients). Noteworthy, reduced lung function was associated with ventricular dilatation. LV enddiastolic volume (by trend) and LV endsystolic volume was increased from GOLD stage I through stage II to stage III (p = 0.048 for GOLD III vs. I). LVEF and LV mass was not different among GOLD stages. Reduced FEV1 was correlated with increased LVEDV (p = 0.0210) and LVESV (p = 0.0413) and with increased LV enddiastolic (p = 0.0161) and endsystolic LV wall stress (p = 0.0315), respectively. LV enddiastolic wall stress (p = 0.048) and LV endsystolic wall stress (p = 0.034) increased from GOLD I to III. In a subgroup of patients with non-ischemic dilated cardiomyopathy, reduced FEV1 was correlated with increased LV enddiastolic (p = 0.0693) and endsystolic wall stress (p = 0.0539) by trend.
Conclusion: Reduced lung function (FEV1) was correlated with increased LV enddiastolic and endsystolic wall stress. It is suggested that respiration at a level of hyperinflation requires increased negative pleural pressure when compared with normal lung function, which is transmitted to the heart and increases the transmural pressure gradient and thereby distending forces on the LV. Additionally proinflammatory processes in COPD potentially invoked in early processes of cardiac dilatation should be taken into account. Increased ventricular wall stress is known to exhibit various unfavourable consequences in heart failure, which could also contribute substantially to a worse prognosis in COPD.