Computed Tomographic Assessment for Cardiac Dysynchrony

Current echocardiographic methods for assessment of cardiac function are only able to view a section, or window, of the heart at one time.  CT scanning has the advantage of imaging the entire heart in a brief span of time.  This imaging information may be useful in identifying areas of the heart that activate abnormally or contain scarred tissue.  The imaging information may also be helpful in identifying the optimum areas to target for cardiac resynchronization therapy.  We are currently working on a new approach using this information to provide more optimized biventricular pacing for patients with heart failure.

Registration of Non-Fluoroscopic Navigation System with 3D Models from CT Scanning

Placement of a biventricular pacing lead in a distal branch of the coronary tree can be difficult in many patients with heart failure and left bundle branch block. We are developming a registration approach to combine accurate three dimensional images of the heart and its vasculature with a non-fluroscopic navigation system to identify the most beneficial site for pacing and to aid in placment of the left ventricular lead in these patients.

Dominant Frequency Analysis of Atrial Fibrillation

The most frequently used approaches to ablation for atrial fibrillation are primarily anatomically based.  While proven safe, the success rate in these procedures is limited and could be improved.  One important theory for the mechanism of atrial fibrillation is that it is maintained by high frequency “rotors” that are needed to sustain this rhythm.  To date, there are not adequate techniques for mapping these rotors within the heart.  We are working to develop dominant frequency mapping algorithms to aid in mapping this complex rhythm and potentially improve the outcome of ablation procedures.

Rotational Angiography for Left Atrial Volume Reconstruction     

ECG gated computed tomography provides high quality images of the heart.  However, these images do not reflect changes in the anatomy due to various factors such as changing blood volume, changing cardiac rhythm, or differences in patient position and orientation.  These factors may have a significant role in affecting the outcome of various cardiac procedures.  Rotational angiography has the potential advantage of creating 3D images of the heart at the time of a patient’s interventional procedure using fluoroscopy.  This could reduce or eliminate all of the above limitations of CT.  We are conducting ongoing studies to determine the optimal methods for rotational angiography and utilization of these images in interventional procedures. 

Computed Tomography-Fluoroscopy Integration for Left Atrial Ablation Procedures

Fluoroscopy shows live images of the heart moving with catheters placed within it, but fails to provide precise delineation of the cardiac anatomy. In contrast, computed tomography (CT) can show the anatomy but it does not display catheter movement within the heart.  Combining these two modalities, through a process known as registration, has the potential of achieving both of these ends.  We are conducting ongoing research into this process, including compensation for cardiac cycle and respiratory motion and the possible integration of biplane fluoroscopy systems, yielding true 3D registration.