Deceleration and Acceleration Capacities in Risk Stratification for Arrhythmias in Patients With Chronic Obstructive Pulmonary Disease.

BACKGROUND: Patients with chronic obstructive pulmonary disease (COPD) have an increased risk for both supraventricular and ventricular arrhythmias. Autonomic dysregulation may be responsible for the development of arrhythmias in these patients, and its analysis could be useful for identifying those at high risk for arrhythmias. STUDY QUESTION: Our purpose is to analyze the role of acceleration capacity (AC) and deceleration capacity (DC), novel markers of the autonomic balance, as potential arrhythmic risk predictors in patients with COPD. STUDY DESIGN: We prospectively included 47 patients diagnosed with COPD, and a control group of 64 age-matched subjects without COPD. AC and DC values were obtained using 24-hour Holter monitoring. The arrhythmias were isolated premature atrial complexes, supraventricular tachycardias, isolated premature ventricular beats (PVC), and combined ventricular arrhythmias consisting in ventricular tachycardias or more than 10 PVC per hour. RESULTS: Supraventricular arrhythmias and isolated PVC were more frequent in the COPD group. The DC was significantly lower (3.10 vs. 5.60, P < 0.0001) and AC higher (-4.60 vs. -6.60, P = 0.002) in patients with COPD. DC was identified as a predictor of arrhythmic events with an area under the curve (AUC) for premature atrial complexes >70/d of 0.72 (0.56-0.87, P = 0.013), for supraventricular tachycardias 0.76 (0.62-0.90, P = 0.002), and for combined ventricular arrhythmias 0.69 (0.54-0.82, P = 0.025). AC was predictor only for combined ventricular arrhythmias with an AUC of 0.74 (0.58-0.85, P = 0.002). CONCLUSIONS: Patients with COPD associate a significant autonomic imbalance and a higher incidence of arrhythmias. DC could be a strong predictor for supraventricular and ventricular arrhythmias in patients with COPD with no clinically apparent cardiac disease. AC could be useful alongside with DC regarding the risk for ventricular arrhythmias, but seems to have lesser value as a predictor for supraventricular arrhythmias.

Prevalence and Characteristics of Pulmonary Hypertension Associated with COPD - A Pilot Study in Patients Referred to a Pulmonary Rehabilitation Program Clinic.

OBJECTIVES: Pulmonary hypertension (PH) is a common complication of chronic obstructive pulmo-nary disease (COPD); its prevalence is currently unknown. The objectives of the study were: (a) to provide data on the prevalence of PH among the COPD patients referred to a pulmonary rehabilitation program; (b) to evaluate possible correlations of PH with the severity of COPD, the presence of hypoxemia and polycythemia. MATERIAL AND METHODS: We retrospectively studied 31 consecutive patients with the diagnosis of COPD hospitalised in our clinic in which echocardiography was performed. Spirometry, peripheral oxygen saturation, haematocrit, echocardiography data, history of exacerbations and cardiac comorbidities were obtained from patients records. PH was defined as systolic pulmonary arterial pressure (sPAP) greater than 35 mmHg or by the presence of right ventricle (RV) abnormalities. OUTCOMES: The prevalence of PH was 38.7%. Resting hypoxemia was significantly more frequent in the PH group than in the non PH patients (p=0.019). Other differences were not statistically significant (severity of bronchial obstruction and polycythemia, cardiac comorbidities). The impact of PH on RV was found in only 5 patients with RV enlargement; no patient had RV hypertrophy or RV systolic dysfunction. Suspected "out of proportion" PH (sPAP greater than 50 mmHg) was encountered in 2 out of 12 patients with PH. CONCLUSIONS: The prevalence of PH in patients with COPD was 38.7%. Resting hypoxemia was significantly more frequent in PH patients. As PH has an important role in the prognosis of COPD patients, it should be evaluated in as many COPD patients as possible.