Noninvasive pulmonary transit time: A new parameter for general cardiac performance

Introduction Pulmonary transit time (PTT) assessed with contrast‐enhanced ultrasound (CEUS) is a novel tool to evaluate cardiac function. PTT represents the time for a bolus of contrast to pass from the right to the left ventricle, measured according to the indicator dilution principles using CEUS. We investigated the hypothesis that PTT is a measure of general cardiac performance in patient populations eligible for cardiac resynchronization therapy (CRT). Methods The study population consisted of heart failure patients referred for CRT with NYHA class II–IV, left ventricular ejection fraction (LVEF)≤35% and QRS≥120 ms. CEUS, ECG, and blood were analyzed, and participants completed a quality of life questionnaire at baseline and 3 months after CRT implantation. Normalized PTT (nPTT) was calculated to compensate for the heart rate. Correlations were assessed with Pearson's or Spearman's coefficients and stratified for rhythm and NYHA class. Results The study population consisted of 94 patients (67 men) with a mean age of 70±8.9 years. (n)PTT was significantly correlated with left ventricular parameters (rs=−.487, P