First experience with real-time magnetic resonance imaging-based investigation of respiratory influence on cardiac function in pediatric congenital heart disease patients with chronic right ventricular volume overload

Abstract

Background Congenital heart disease (CHD) is often associated with chronic right ventricular (RV) volume overload. Real-time magnetic resonance imaging (MRI) enables the analysis of cardiac function during free breathing. Objective To evaluate the influence of respiration in pediatric patients with CHD and chronic RV volume overload. Methods and materials RV volume overload patients (n=6) and controls (n=6) were recruited for cardiac real-time MRI at 1.5 tesla during free breathing. Breathing curves from regions of interest reflecting the position of the diaphragm served for binning images in four different tidal volume classes, each in inspiration and expiration. Tidal volumes were estimated from these curves by data previously obtained by magnetic resonance-compatible spirometry. Ventricular volumes indexed to body surface area and Frank-Starling relationships referenced to the typical tidal volume indexed to body height (TTVi) were compared. Results Indexed RV end-diastolic volume (RV-EDVi) and indexed RV stroke volume (RV-SVi) increased during inspiration (RV-EDVi/TTVi: RV load: + 16 ± 4%; controls: + 22 ± 13%; RV-SVi/TTVi: RV load: + 21 ± 6%; controls: + 35 ± 17%; non-significant for comparison). The increase in RV ejection fraction during inspiration was significantly lower in RV load patients (RV load: + 1.1 ± 2.2%; controls: + 6.1 ± 1.5%; P=0.01). The Frank-Starling relationship of the RV provided a significantly reduced slope estimate in RV load patients (inspiration: RV load: 0.75 ± 0.11; controls: 0.92 ± 0.02; P=0.02). Conclusion In pediatric patients with CHD and chronic RV volume overload, cardiac real-time MRI during free breathing in combination with respiratory-based binning indicates an impaired Frank-Starling relationship of the RV. Graphical Abstract

Relationship between changes in the electrical axis of the heart during inspiration and the structural and functional state of the heart according to echocardiography in patients with precapillary pulmonary hypertension

“…У лиц без признаков сердечной недостаточности задержка дыхания на вдохе приводила к уменьшению конечного диастолического и конечного систолического объемов левого желудочка, уменьшению объема и фракции выброса левого предсердия, уменьшению скорости раннего диастолического наполнения левого желудочка [16]. У детей с врожденными пороками сердца и хронической перегрузкой правого желудочка объемом индексированные конечный диастолический и ударный объемы правого желудочка во время вдоха увеличивались (как и в контрольной группе), однако увеличение фракции выброса правого желудочка во время вдоха было достоверно ниже, а кривая Франка-Старлинга имела значительно меньший наклон, чем в контрольной группе [17].…”