Echocardiographic Diagnosis of a Partially Thrombosed Right Coronary Artery Aneurysm in a Patient with Polycystic Disease

This report describes a patient with polycystic disease of the kidneys and the liver and an aneurysm of the proximal right coronary artery. Transthoracic and transesophageal echocardiographic imaging showed a 5 times 5 cm oval-shaped, spherical tumor in the atrioventricular corner. The tumor was partially filled with homogenous echostructures. Coronary angiography showed aneurysmatic configuration of the right coronary artery, but no region demonstrating a mass of similar size and shape as seen by echocardiography. The finding of a partially thrombosed coronary artery aneurysm was subsequently confirmed by surgery.     

Interstitial cells of Cajal: are they major players in control of gastrointestinal motility?

This review examines recent evidence from structural and functional studies that interstitial cells of Cajal (ICC) play a major role in control of gastrointestinal function. These cells, identified to date only by their structural and somewhat selective staining characteristics, form networks in the region of the myentehc plexus and in or adjacent to circular muscle. Those in circular muscle are often coupled to one another and to smooth muscle cells by gap junctions and are closely innervated by a high proportion of enteric nerves, especially those containing vasoactive intestinal polypeptide (VIP). ICC in the myenteric plexus often have no visible connections by gap junctions to smooth muscle. There is a growing body of evidence from study of small intestine and colon that these cells are either the pacemakers or provide clocks for the pacemaking function of the gut (vahously known as slow waves, pacesetter potentials or control potentials). Additional evidence suggests that they may play a role in neurotransmission of non-adrenergic, non-cholinergic inhibitory activity. This review summarizes our current understanding and attempts to point the way for future research.     

Bidirectional Bundle Branch Reentry Tachycardia Associated with Ebstein's Anomaly: Cured by Extensive Cryoablation of the Right Bundle Branch

A 30-year-old woman with Ebstein's anomaly presented with a sustained, wide QRS complex tachycardia exhibiting a left bundle branch block morphology. Serial electrophysiological studies revealed right and left bundle branch reentry tachycardias refractory to many conventional antiarrhyfhmic drugs, Radiofrequency and direct current catheter ablation of the right bundle branch failed to control the tachycardias. The patient subsequently underwent extensive endocardial cryoablation to the right bundle branch resulting in cure of her arrhythmia.     

Amplitude and Direction of Atrial Depolarization Using a Multipolar Floating Catheter: Principles for a Single Lead VDD Pacing

VDD stimulation using a single catheter for atrial sensing and ventricular sensing and pacing has become a reality. In order to compare the quality of the cavitary atrial electrogram (AEG) and to determine the intraatrial P wave direction and conduction time (CT), we compared, in an acute study, three different types of atrial electrode systems using four different leads, in 53 patients in sinus rhythm. The three electrode systems were: (1) one experimental system with quadripolar orthogonal electrodes using the Goldreyer concept; (2) one experimental system with quadripolar whole ring electrodes; (3) two systems with diagonally oriented half-ring electrodes, one experimental quadripolar and one bipolar CCS commercial (Polysafe A-Track lead). For the experimental systems, the four electrodes forming two independent bipolar pairs were situated on the intraatrial floating portion of a single lead and one supplemental electrode was distally positioned in the right ventricular apex. Bipolar AEGs were recorded at the high and at the low levels of the right atrium. For the CCS lead, the single bipolar AEG was recorded at the high level of the right atrium only. The highest AEG amplitude and the highest values for ventricular far-field rejection were provided by both diagonally oriented half-ring electrodes at the high atrial level and by the whole ring electrodes at the low atrial level. For both atrial levels, the orthogonal electrode system provided the smallest AEG amplitudes, the highest ventricular electrogram amplitudes, and therefore, the smallest values for ventricular far-field rejection.(ABSTRACT TRUNCATED AT 250 WORDS)     

Optimal Stimulation of the Left Ventricle

Optimal Stimulation of the Left Ventricle. Cardiac resynchronization therapy has been proposed to alleviate heart failure symptoms refractory to classic drug treatment. Potential benefits hinge on a number of key components, including judicious selection of patients likely to respond to the therapy and appropriate placement of the leads, particularly the lead responsible for left ventricular pacing. Evidence of ventricular asynchrony is an individual prerequisite for consideration of cardiac resynchronization therapy. Ventricular asynchrony can be diagnosed by recording a QRS duration > 150 msec or during echocardiography, with the goal of investigating the mechanical aspect of asynchrony. The optimal left ventricular pacing site can be defined by the latest segmental contraction, which is mainly the mid‐lateral wall. The first‐choice technique to initiate left ventricular pacing consists of a transvenous approach via the coronary sinus tributaries. In practice, the final left ventricular pacing location also depends on highly variant coronary sinus anatomy, acceptable electrical parameters, and lead stability. Procedure‐related complications, which consist mainly of coronary sinus perforation and phrenic nerve stimulation, remain low (<1%) and should decrease further with the use of new features specific to the procedure.