Effects of Dynamic Hyperinflation on Left Ventricular Diastolic Function in Healthy Subjects — A Randomized Controlled Crossover Trial

Abstract

Objective: Diastolic dysfunction of the left ventricle is common in patients with chronic obstructive pulmonary disease (COPD). Dynamic hyperinflation has been suggested as a key determinant of reduced diastolic function in COPD. We aimed to investigate the effects of induced dynamic hyperinflation on left ventricular diastolic function in healthy subjects to exclude other confounding mechanisms associated with COPD.Design: In this randomized controlled crossover trial (NCT03500822, https://www.clinicaltrials.gov/), we induced dynamic hyperinflation using the validated method of expiratory resistance breathing (ERB), which combines tachypnea with expiratory resistance, and compared the results to those of tachypnea alone. Healthy male subjects (n = 14) were randomly assigned to the ERB or control group with subsequent crossover. Mild, moderate, and severe hyperinflation (i.e., ERB1, ERB2, ERB3) were confirmed by intrinsic positive end-expiratory pressure (PEEPi) using an esophageal balloon catheter. The effects on diastolic function of the left ventricle were measured by transthoracic echocardiographic assessment of the heart rate-adjusted transmitral E/A-ratio and E/e'-ratio.Results: We randomly assigned seven participants to the ERB group and seven to the control group (age 26 [24-26] vs. 24 [24-34], p = 0.81). Severe hyperinflation decreased the E/A-ratio compared to the control condition (1.63 [1.49–1.77] vs. 1.85 [0.95–2.75], p = 0.039), and moderate and severe ERB significantly increased the septal E/e'-ratio. No changes in diastolic function were found during mild hyperinflation. PEEPi levels during ERB were inversely correlated with the E/A ratio (regression coefficient = −0.007, p = 0.001).Conclusions: Our data indicate dynamic hyperinflation as a determinant of left ventricular diastolic dysfunction in healthy subjects. Therapeutic reduction of hyperinflation might be a treatable trait to improve diastolic function in patients with COPD.

Utility of Cardiopulmonary Exercise Testing in Chronic Obstructive Pulmonary Disease: A Review

“… 30 It is also recognized that patients with heart failure, either with preserved 31 or reduced 32 ejection fraction who have comorbid COPD have worse functional class than those without lung disease. 33 Hyperinflation has again been implicated in this as it has been associated with more left ventricular diastolic impairment and reduced performance on the six-minute walk test (6MWT). Reduction of hyperinflation with rigorous bronchodilator therapy is also reported to increase end diastolic volumes.…”

Cardio-respiratory interactions in acute asthma

“…At high levels of inflation and in hearts with greater volume, increased septal flattening suggests that left ventricular underfilling during hyperinflation may be primarily a result of ventricular interaction exacerbated by ventricular interdependence ( Robotham et al, 1983 ). In a randomized controlled trial conducted by Urban et al (2021) , it was demonstrated that dynamic pulmonary hyperinflation has a notable impact on left heart diastolic function, expressed as the E/A ratio in echocardiography, and leads to an increase in ventricular filling pressures, as indicated by the E/e' ratio. They highlighted an inverse correlation between positive end expiratory pressure and E/A ratio.…”