Effects of CPAP and BILEVEL on cardiac autonomic function and hemodynamic and ventilatory variables after acute myocardial infarction

Abstract

Introduction: Cardiovascular diseases, especially acute myocardial infarction (AMI), represent the major cause of mortality and morbidity in the world. Myocardial ischemia is often the precipitating cause of pulmonary edema and non invasive ventilation (NIV) with positive pressure has been used as a therapeutic modality. Objective: To evaluate the effects of NIV on heart rate variability (HRV) and on ventilatory and hemodynamic variables in patients with myocardial infarction. Methods: Ten patients with acute myocardial infarction, with Killip I classification, used CPAP and Bilevel ventilation during 30 minutes, according to a crossover randomization. Ventilatory and hemodynamic variables were registered and electrocardiogram signals were recorded for posterior analyses of HRV. Data were collected before, during and after positive pressure ventilation. Data were compared using Anova Repeated Measures or Kruskal-Wallis Anova on Ranks, followed by Tukey test. Results: There was significant increase of SpO2 during use of CPAP and Bilevel when compared to pre ventilation period (p=0.003) returning to the initial values after 15 minutes. Bilevel led to significant reduction of respiratory rate (p = 0.018) and double product (p = 0.006). Only CPAP promoted significant reduction in heart rate, and these variables returned to pre ventilation values, immediately after the procedure. There are not alterations in HRV in both techniques. Conclusion: the use of CPAP and Bilevel, in patients with myocardial infarction, with Killip I classification, led to ventilatory and hemodynamic repercussions without alterations in cardiac autonomic control, at the time of application. NCT01484795.