Investigation of hemodynamics in an in vitro system simulating left ventricular support through the right subclavian artery using 4-dimensional flow magnetic resonance imaging

Background Pulmonary arterial hypertension (PAH) manifests with progressive right ventricular (RV) dysfunction, which eventually impairs the left ventricular function. We hypothesized that 4‐dimensional–flow magnetic resonance imaging can detect flow hemodynamic changes associated with efficient intracardiac flow during noninvasive inhaled nitric oxide (iNO) challenge in children with PAH. Methods and Results Children with PAH (n=10) underwent 2 same‐day separate iNO challenge tests using: (1) 4‐dimensional–flow magnetic resonance imaging and (2) standard catheterization hemodynamics. Intracardiac flow was evaluated using the particle tracking 4‐flow component analysis technique evaluating the direct flow , retained inflow , delayed ejection flow , and residual volume . Respective flow hemodynamic changes were compared with the corresponding catheterization iNO challenge results. The RV analysis revealed decreased direct flow in patients with PAH when compared with controls ( P <0.001) and increase in residual volume ( P <0.001). Similarly, the left ventricular analysis revealed decreased direct flow in patients with PAH when compared with controls ( P =0.004) and increased proportion of the residual volume ( P =0.014). There was an increase in the RV direct flow during iNO delivery ( P =0.009), with parallel decrease in the residual volume ( P =0.008). Conclusions Children with PAH have abnormal biventricular flow associated with impaired diastolic filling. The flow efficiency is significantly improved in the RV on iNO administration with no change in the left ventricle. The changes in the RV flow have occurred despite the minimal change in catheterization hemodynamics, suggesting that flow hemodynamic evaluation might provide more quantitative insights into vasoreactivity testing in PAH.

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Cardiac magnetic resonance imaging in a patient with temporary external pacemaker: a case report

European Heart Journal - Case Reports ◽

10.1093/ehjcr/ytz228 ◽

2019 ◽

Vol 3 (4) ◽

pp. 1-4 ◽

Cited By ~ 3

Author(s):

Uzma Chaudhry ◽

Jonas Svensson ◽

Henrik Mosén ◽

David Mörtsell

Keyword(s):

Magnetic Resonance Imaging ◽

Cardiovascular Magnetic Resonance ◽

Magnetic Resonance ◽

Pulse Generator ◽

Imaging Modality ◽

Acute Myocarditis ◽

Left Ventricular ◽

Resonance Imaging ◽

History Of ◽

The Right

Abstract Background Magnetic resonance imaging (MRI) is increasingly becoming the imaging modality of choice for many clinical disorders due to superior image quality and absence of radiation. However, access to MRI remains limited for most patients with cardiac implantable electronic devices due to potential safety concerns. In line with guidelines, there is no absolute contraindication to perform MRI, but warrants careful risk-benefit assessment. Case summary A 59-year-old man was admitted with a 5-day history of central chest pain and few week’s history of general malaise, dry cough, and breathlessness. Electrocardiogram confirmed complete atrioventricular block (CAVB). A slight increase in cardiac enzyme was noted. Coronary angiogram revealed atheromatous changes, but no obstructive coronary lesion. A temporary transvenous pacemaker was inserted. Transthoracic echocardiogram confirmed a dilated left ventricle with severely reduced left ventricular function. To facilitate diagnosis (hence prognosis), management and mobilization, investigation with cardiovascular magnetic resonance (CMR) was warranted but contraindicated by the temporary transvenous pacemaker. An active fixation pacemaker lead was therefore placed in the right ventricle via percutaneous puncture of the right subclavian vein and connected to a pulse generator, both secured to the skin with sutures and adhesive medical dressing. Appropriate device programming and close patient monitoring ensured that CMR could be performed without any adverse effects. A diagnosis of acute myocarditis was confirmed. Regular device interrogation during an extended 3-week period with temporary pacing ruled out any device failure. As there was no resolution of CAVB, the patient received a dual-chamber pacemaker. Discussion Cardiovascular magnetic resonance was feasible and safely performed on a patient with a temporary permanent external pacemaker system using a standard screw-in pacing lead and a regular pulse generator fixed to the skin. Although more studies are needed for generalizability, CMR may be used in highly selected patients with a temporary pacemaker.

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High Resolution Simulation of Diastolic Left Ventricular Hemodynamics Guided by Four-Dimensional Flow Magnetic Resonance Imaging Data

Flow Turbulence and Combustion ◽

10.1007/s10494-018-0003-7 ◽

2019 ◽

Vol 102 (1) ◽

pp. 3-26

Author(s):

Trung Bao Le ◽

Mohammed S. M. Elbaz ◽

Rob J. Van Der Geest ◽

Fotis Sotiropoulos

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

High Resolution ◽

Left Ventricular ◽

Imaging Data ◽

Resonance Imaging ◽

Magnetic Resonance Imaging Data ◽

Dimensional Flow ◽

Resolution Simulation

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Accurate Assessment of Left Ventricular Mass by 3D-Echo: Comparison to Magnetic Resonance Imaging

Journal of the American College of Cardiology ◽

10.1016/s0735-1097(97)85600-8 ◽

1998 ◽

Vol 31 (2) ◽

pp. 436A

Author(s):

H Kühl

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Left Ventricular Mass ◽

Left Ventricular ◽

Accurate Assessment ◽

Resonance Imaging ◽

Ventricular Mass ◽

3D Echo

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Dependence of Blood Clot Lysis on the Mode of Transport of Urokinase into the Clot - A Magnetic Resonance Imaging Study in Vitro

Thrombosis and Haemostasis ◽

10.1055/s-0038-1648188 ◽

1991 ◽

Vol 65 (05) ◽

pp. 549-552 ◽

Cited By ~ 55

Author(s):

A Blinc ◽

G Planinšič ◽

D Keber ◽

O Jarh ◽

G Lahajnar ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Pressure Difference ◽

Volume Flow Rate ◽

Blood Clot ◽

Linear Regression Analysis ◽

Imaging Study ◽

Clot Lysis ◽

Resonance Imaging

SummaryMagnetic resonance imaging was employed to study the dependence of clot lysing patterns on two different modes of transport of urokinase into whole blood clots. In one group of clots (nonperfused clots, n1 = 10), access of urokinase to the fibrin network was possible by diffusion only, whereas in the other group (perfused clots, n2 = 10) bulk flow of plasma containing urokinase was instituted through occlusive clots by a pressure difference of 3 .7 kPa (37 cm H2O) across 3 cm long clots with a diameter of 4 mm. It was determined separately that this pressure difference resulted in a volume flow rate of 5.05 ± 2.4 × 10−2 ml/min through occlusive clots. Perfused clots diminished in size significantly in comparison to nonperfused ones already after 20 min (p <0.005). Linear regression analysis of two-dimensional clot sizes measured by MRI showed that the rate of lysis was more than 50-times faster in the perfused group in comparison to the nonperfused group. It was concluded that penetration of the thrombolytic agent into clots by perfusion is much more effective than by diffusion. Our results might have some implications for understanding the differences in lysis of arterial and venous thrombi.

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