Mode 2 gating of L-type Ca channels is characterized by high channel open probability ( NP o) and long openings. In cardiac myocytes, this mode is evoked physiologically in two apparently different circumstances: membrane depolarization (prepulse facilitation) and activation of protein kinase A. To examine whether the phosphorylation mechanism is involved during prepulse-induced facilitation of...

In cardiac MR imaging of mice a variety of different imaging techniques are available[1-2], ranging from morphometry, strain and velocity imaging, angiography, to perfusion and myocardial function, to name a few. In this report examples of cardiac MR imaging applications in mice are provided with a focus on morphometric and cardiac function assessment. Practical considerations for cardiac MR in...

Mutations in the gene (SCN5A) encoding the alpha-subunit of the cardiac Na+ channel cause congenital long QT syndrome (LQT-3). Here we describe a novel LQT-3 mutation I1768V (I1768V) located in the sixth transmembrane spanning segment of domain IV. This mutation is unusual in that it is located within a transmembrane spanning domain and does not promote the typically observed sustained inward c...

P. Chalasani, D. N. Sandman, M. Crowe, O. P. Simonetti, E. Wu, J. Carr, A. Larson Advocate Illinois Masonic Medical Center, Chicago, Illinois, United States, Northwestern University, Chicago, Illinois, United States, Ohio State University, Columbus, Ohio, United States Introduction: Electrocardiogram (ECG)-gating uses an R-wave trigger to synchronize segmented cine data acquisition to the cardi...

Navigator echoes (NAVs) provide an effective means of monitoring physiological motion in magnetic resonance imaging (MRI). Motion artifacts can be suppressed by adjusting the data acquisition accordingly. The standard pencil-beam NAV has been used to detect diaphragm motion; however, it does not monitor cardiac motion effectively. Here we report a navigator approach that directly measures coron...

A motion artifact suppression technique (MAST) has recently been developed that significantly reduces motion artifacts in conventional 2DFT imaging. The technique utilizes modifications of slice-select and read gradient waveforms to eliminate velocity, acceleration, and pulsatility phase shifts that occur between the 90 degrees pulse and data collection. T2-weighted cranial MAST images were rat...

Background Cardiac gating in ultra high field (UHF) MRI is a challenging task due to the magnetohydrodynamic (MHD) effect [1]. The MHD effect is particularly severe at such field strengths and severely distorts the electrocardiogram (ECG). State-of-the-art ECG based gating methods which use the vectorcardiogram (VCG) [2] are thus prone to errors [1]. This work presents an approach which separat...

Micro-CT is widely used in preclinical studies, generating substantial interest in extending its capabilities in functional imaging applications such as blood perfusion and cardiac function. However, imaging cardiac structure and function in mice is challenging due to their small size and rapid heart rate. To overcome these challenges, we propose and compare improvements on two strategies for c...

Purpose: The fundamental spatial resolution of in vivo MR lung imaging is limited by motion in thoracic cavity [1]. This problem is particularly evident in microscopic lung imaging of rodents because of their high cardiac (400-700 bpm) and breathing rate (100-150 breaths/min). To overcome these limitations several methods have been proposed, including scan-synchronous ventilation [2] and cardia...

Cardiac action potentials (AP) are produced by the orchestrated functions of ion channels. A slight change in ion channel activity may affect the AP waveform, thereby potentially increasing susceptibility to abnormal cardiac rhythms. Cardiac ion channels are heavily glycosylated, with up to 30% of a mature protein's mass comprised of glycan structures. However, little is known about how reduced...