Tricuspid valve endocarditis

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Atrial flutter: historical background

For five decades, the mechanism of atrial flutter remained controversial, with protagonists and antagonists of circus movement versus ectopic focus theories. The development of clinical electrophysiology in the 1970s and the observations made by many authors in various canine heart models supported the concept of atrial flutter as a reentrant wave confined to the right atrium. It was established that, in the common type of atrial flutter, the activation wavefront proceeds in a cranial direction over the right atrial septum and descends on the right atrial free wall in the caudal direction. A zone of slow conduction was identified inferiorly and posteriorly in the right atrium, target of the modern ablative techniques. The history of atrial flutter clearly illustrates the bidirectional flow of information and the mutual stimulation between the basic and the clinical levels, leading both to a better understanding of the nature of the arrhythmia and to new therapeutic approaches.

Percutaneous balloon pericardiotomy: a case report and analysis of mechanism of action

A 33-year-old man with acquired immunodeficiency syndrome (AIDS) and cardiac tamponade underwent percutaneous balloon pericardiotomy. To elucidate the pathway of fluid elimination, at the end of the procedure, we injected methylene blue into the pericardial space. Contrary to previous belief, we found no blue discoloration of the pleural fluids, and thus we postulate that most of the fluid was eliminated by peritoneal resorption.

Variability in estimation of coronary dimensions from 6F and 8F catheters

To investigate the suitability of diagnostic 6F catheters for coronary angiographic measures in the clinical setting, we determined the relative accuracy and reproducibility of the measures obtained with these catheters as scaling devices in 59 stenoses. Comparison was made with duplicate injections, obtained before angioplasty, using an 8F guiding catheter as scaling device. Intra- and interobserver variability was evaluated in 15 stenoses. The coefficient of variation averaged 18.3% for the minimal lumen diameter, 10.4% for the percent stenosis, and only 7.4% for the reference diameter. Reproducibility of angiographic measures done with the 6F catheter was similar to that obtained with the 8F catheter, although accuracy was lower with the 6F for the measurement of reference diameter. Thus, quantitative coronary angiography (QCA) measures derived from routine diagnostic angiograms may be suitable for determination of reference diameter, allowing enough precision for determination of the size of a coronary device for intervention, but these measures may lack accuracy for precise determination of minimum diameter and percent stenosis, making their use questionable in studies looking at individual changes in coronary stenosis dimensions.

Rhythmic and electrophysiological study after dynamic cardiomyoplasty

To question the possible proarrhythmic effects of cardiomyoplasty (CMP), six adult goats were submitted to rhythmic and electrophysiological (EP) study 15 days before and 8 months after a posteroanterior clockwise CMP procedure using Medtronic Cardiomyostimulator (CMS) (SP1005) and electrodes (SP5528) and completion of a progressive stimulation protocol. Pre and postoperative screening included a surface ECG, 24-hour Holter monitoring, high amplitude and filtered QRS averaging, and invasive EP study performed in the postoperative period with the CMS "ON" and "OFF." One-hour Holter recording with desynchronization of the CMS was obtained. Comparison of pre and postoperative ECG and rhythmic data showed no significant difference. High amplitude QRS averaging did not evidence meeting the usual criteria of late potentials. EP values were stable in both conditions and the aggressive EP program did not show evidence of increased susceptibility to arrhythmias. Asynchronous cardiomyostimulation did not induce arrhythmias. Our data strongly suggest that provided meticulous surgical technique is used, CMP does not significantly interfere with the electrical characteristics of the normal goat heart. The procedure, despite the disturbances it provokes, does not seem to be arrhythmogenic. The function of the CMS was always appropriate, even under stressful EP conditions.