Intrapericardial echocardiography: a novel catheter-based approach to cardiac imaging.
BACKGROUND
Transvascular catheter-based intracardiac echocardiography has been successfully used to help guide catheter ablation and electrophysiologic procedures. It has recently been demonstrated that catheters can be safely placed into the pericardial space to allow for epicardial cardiac mapping and ablation. We evaluated the feasibility of catheter-based intrapericardial echocardiography (IPE) during such procedures to identify cardiac structures and visualize intracardiac catheters.


METHODS
IPE was performed in 7 goats by placing a phased-array ultrasound transducer contained within a 10F steerable catheter into the pericardial space using the same transthoracic subxyphoid approach as used to map and ablate epicardial ventricular tachycardia. Images were obtained of cardiac structures and of intracardiac ablation catheters. After the procedure, the hearts were harvested to assess for possible IPE-related lesions.


RESULTS
The IPE catheter could be easily placed inside the pericardial space in all animals. In 7 of 7 cases, longitudinal and short-axis views of right- and left-sided chambers and valves were obtained, similar in orientation to transesophageal echocardiography. Visualization of atrial appendages (6/7), pulmonary veins (6/7), coronary arteries (6/7), and coronary sinus (3/6) was also feasible. Assessment of intracardiac transvalvar and venous blood flow was achieved by spectral and color Doppler. The ablation catheter could be clearly visualized inside cardiac chambers. No arrhythmias were induced with IPE catheter manipulation. After harvesting the hearts, no lesions resulting from the procedure were observed.


CONCLUSIONS
In this experimental setting, IPE was able to provide detailed images of cardiac structures and establish the relative position of the ablation catheter.
Cardiac Arrhythmia Service, Massachusetts General Hospital, 55 Fruit Street, GRB 109, Boston, MA 02114, USA.
Ana Clara Tude
AC
Rodrigues
Andre
A
d'Avila
Christopher
C
Houghtaling
Jeremy N
JN
Ruskin
Michael
M
Picard
Vivek Y
VY
Reddy
D000818:Animals; D001021:Aortic Valve / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D006328:Cardiac Catheterization / Q000295:instrumentation; D002408:Catheters, Indwelling; D003331:Coronary Vessels / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D004452:Echocardiography / Q000295:instrumentation; D022062:Electrophysiologic Techniques, Cardiac; D006041:Goats; D006325:Heart Atria / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D006346:Heart Septum / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D006352:Heart Ventricles / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D007089:Image Enhancement; D008943:Mitral Valve / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D023421:Models, Animal; D008955:Models, Cardiovascular; D010210:Papillary Muscles / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D010496:Pericardium / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D011664:Pulmonary Valve / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D012016:Reference Values