Effects of Ivabradine on Right Ventricular Systolic Function in Patients With Chronic Obstructive Pulmonary Disease and Cor Pulmonale

Cor pulmonale is a clinical syndrome associated with pulmonary hypertension, frequently complicated by congestive heart failure, commonly caused by chronic obstructive pulmonary disease (COPD). Most patients with cor pulmonale have tachycardia. However, heart rate (HR) reduction represents a primary treatment goal to improve the survival and quality of life in these patients. Ivabradine can selectively slow HR at rest and during exercise. In this prospective study, we tested the hemodynamic effects, invasively determined using right-sided cardiac catheterization, of reducing HR with ivabradine. We selected 18 patients (13 men [72.2%], mean age 67 ± 10 years) with COPD and cor pulmonale, presenting with sinus tachycardia. All patients performed clinical evaluation, electrocardiogram, spirometry, echocardiogram, 6-minute walking distance, and right-sided cardiac catheterization within 1 month of enrollment. All tests were repeated after 6 months of ivabradine treatment (median assumed dose 11.9 mg/die). We noticed a significant decrease of HR (from 98 ± 7 to 77 ± 8 beats/min, p = 0.0001), with a concomitant reduction of the congestion index (from 25.9 ± 5.1 to 19.4 ± 5.7 mm Hg, p = 0.001), and the consequent improvement of the right ventricular systolic performance (right ventricular stroke volume augmented from 56.7 ± 7.9 to 75.2 ± 8.6 ml/beat, p = 0.0001). This allows an improvement in clinical status and exercise tolerance (Borg scale score decreased from 5.2 ± 1.4 to 4.1 ± 1.3, p = 0.01 and the 6-minute walking distance increased to 252 ± 65 to 377 ± 59 m, p = 0.001). In conclusion, HR reduction significantly improves hemodynamic and clinical status of patients with tachycardia affected by COPD and cor pulmonale.