Excess Ventilation in Chronic Obstructive Pulmonary Disease–Heart Failure Overlap. Implications for Dyspnea and Exercise Intolerance

The strength of the respiratory muscles can be evaluated from static measurements (maximal inspiratory and expiratory pressures, MIP and MEP) or inferred from dynamic maneuvers (maximal voluntary ventilation, MVV). Although these data could be suitable for a number of clinical and research applications, no previous studies have provided reference values for such tests using a healthy, randomly selected sample of the adult Brazilian population. With this main purpose, we prospectively evaluated 100 non-smoking subjects (50 males and 50 females), 20 to 80 years old, selected from more than 8,000 individuals. Gender-specific linear prediction equations for MIP, MEP and MVV were developed by multiple regression analysis: age and, secondarily, anthropometric measurements explained up to 56% of the variability of the dependent variables. The most cited previous studies using either Caucasian or non-Caucasian samples systematically underestimated the observed values of MIP (P<0.05). Interestingly, the self-reported level of regular physical activity and maximum aerobic power correlates strongly with both respiratory and peripheral muscular strength (knee extensor peak torque) (P<0.01). Our results, therefore, provide a new frame of reference to evaluate the normalcy of some useful indexes of respiratory muscle strength in Brazilian males and females aged 20 to 80.

To establish the prevalence of unrecognized heart failure in elderly patients with a diagnosis of chronic obstructive pulmonary disease, in a stable phase of their disease. In a cross-sectional study, patients >/=65 years of age, classified as having chronic obstructive pulmonary disease by their general practitioner and not known with a cardiologist-confirmed diagnosis of heart failure, were invited to our out-patient clinic. Four hundred and five participants underwent an extensive diagnostic work-up, including medical history and physical examination, followed by chest radiography, electrocardiography, echocardiography, and pulmonary function tests. As reference (i.e. 'gold') standard the consensus opinion of an expert panel was used. The panel based the diagnosis of heart failure on all available results from the diagnostic assessment, guided by the diagnostic principles of the European Society of Cardiology (ESC) for heart failure (i.e., symptoms and echocardiographic systolic and/or diastolic dysfunction). The diagnosis of chronic obstructive pulmonary disease was based on the diagnostic criteria of the Global Initiative (GOLD) for chronic obstructive pulmonary disease. Of 405 participating patients with a diagnosis of chronic obstructive pulmonary disease, 83 (20.5%, 95% CI 16.7-24.8) had previously unrecognized heart failure (42 patients systolic, 41 'isolated' diastolic, and none right-sided heart failure). In total, 244 (60.2%) patients had chronic obstructive pulmonary disease according to the GOLD criteria and 50 (20.5%, 95% CI 15.6-26.1) patients combined with unrecognized heart failure. Unrecognized heart failure is very common in elderly patients with stable chronic obstructive pulmonary disease. Closer co-operation among general practitioners, pulmonologists, and cardiologists is necessary to improve detection and adequate treatment of heart failure in this large patient population.

Pulmonary disease is common in patients with heart failure, through shared risk factors and pathophysiological mechanisms. Adverse pulmonary vascular remodelling and chronic systemic inflammation characterize both diseases. Concurrent chronic obstructive pulmonary disease presents diagnostic and therapeutic challenges, and is associated with increased morbidity and mortality. The cornerstones of therapy are beta-blockers and beta-agonists, whose pharmacological properties are diametrically opposed. Each disease is implicated in exacerbations of the other condition, greatly increasing hospitalizations and associated health care costs. Such multimorbidity is a key challenge for health-care systems oriented towards the treatment of individual diseases. Early identification and treatment of cardiopulmonary disease may alleviate this burden. However, diagnostic and therapeutic strategies require further validation in patients with both conditions.