Search PubMed⌕ Search

Biomedical subjects

P Rizzon

Publications and source records attributed to P Rizzon.

At least 199 records · Page 11Linked to original sources
PubMed1985

Detection of coronary artery disease by two-dimensional echocardiography and transesophageal atrial pacing.

Two-dimensional echocardiography was performed at rest and during rapid transesophageal atrial pacing in 85 patients undergoing coronary arteriography for evaluation of chest pain. Transesophageal atrial pacing was performed with 10 ms pulses of 6 to 27 mA intensity; the rate was progressively increased up to 150 beats/min. Four patients were excluded: two because atrial capture was not achieved and two because of chest discomfort induced during transesophageal atrial pacing. Of the remaining 81 patients, 56 had significant coronary artery disease (greater than or equal to 75% stenosis of at least one major coronary vessel) and 25 had no significant coronary artery disease; 25 of the 56 patients with coronary artery disease had no wall motion abnormalities at rest. The test was considered positive if wall motion abnormalities were detected during pacing. Wall motion abnormalities occurred in 3 of 25 patients without coronary artery disease (specificity 88%) and in 51 of 56 patients with coronary artery disease (sensitivity 91%). Wall motion abnormalities developed in 20 of the 25 patients with coronary artery disease and normal regional wall motion at rest (sensitivity 80%); sensitivity for one, two and three vessel disease was 85% (17 of 20 patients), 94% (15 of 16 patients) and 95% (19 of 20 patients), respectively. In patients without coronary artery disease, wall motion score was 18 at rest and 17.7 +/- 0.9 during pacing (p = NS). In patients with coronary artery disease, wall motion score decreased from 15.2 +/- 3.6 at rest to 11.6 +/- 4.1 during pacing (p less than 0.001). In patients with coronary artery disease and normal regional wall motion at rest, wall motion score decreased from 18 at rest to 14.4 +/- 3.1 during pacing (p less than 0.001). Thus, two-dimensional echocardiography during transesophageal atrial pacing appears both sensitive and specific in detecting patients with coronary artery disease. This new procedure is a feasible and reliable alternative to exercise two-dimensional echocardiography.

Adult↗
PubMed1985

Effect of adenosine and adenosine-5'-triphosphate on atrioventricular conduction in patients.

This study was carried out to further elucidate the effects of adenosine and adenosine-5'-triphosphate (ATP) on atrioventricular (AV) conduction in patients. Adenosine (0.24 mg/kg) and ATP (0.28 mg/kg) were administered intravenously to 37 patients undergoing intracardiac electrophysiologic evaluation. Both adenosine and ATP depressed AV conduction by lengthening the atrial to His bundle (AH) interval. The effects of adenosine and ATP after rapid intravenous bolus administration were fast in onset (15 +/- 0.5 and 15 +/- 1.5 s, respectively), but transient in duration (10.5 +/- 0.5 s for ATP and 17 +/- 3 s for adenosine). Although muscarinic blockade with 0.04 mg/kg atropine shortened the AH interval from a control value of 123 +/- 12 to 74 +/- 4 ms, it did not modify the effects of adenosine or ATP, or both (that is, latency and duration of the effects were not significantly different from before atropine administration). In contrast, aminophylline, a competitive antagonist of adenosine, completely prevented the effects of adenosine and ATP. Aminophylline alone also shortened the AH interval from a control value of 98 +/- 9 to 74 +/- 9 ms. This decrease was blocked by propranolol (0.1 mg/kg), whereas propranolol did not influence the ability of aminophylline to antagonize the effects of adenosine or ATP, or both. Thus, the catecholamines released by aminophylline are unlikely to account for the ability of aminophylline to antagonize the effects of adenosine and ATP. In conclusion, these findings indicate that intravenously administered adenosine and ATP are equally effective in producing AV block that is antagonized by aminophylline but not by atropine.

Adenosine↗
PubMed1985

[Evaluation of the ejection fraction using 2 simplified echocardiographic methods in patients with ischemic heart disease and left ventricular asynergy].

UNLABELLED: This study was undertaken to assess the reliability of two simplified echocardiographic methods (Method A and B) in evaluating ejection fraction (E.F.) in patients with left ventricular wall motion abnormalities (WMA). Method A was obtained with a microprocessor that allows the superimposition of a calibrated ellipse to left ventricular end-diastolic and end-systolic silhouettes; the shape of the ellipse was modified to obtain the best superimposition of the ellipse outline to the endocardium. E.F. was then obtained with the formula: VD-VS/VD where VD and VS were the ellipse volumes at end-diastole and end-systole. In method B E.F. was obtained averaging 3 regional E.F. obtained with a longitudinal axis and 3 different transverse diameters. In a group of 40 patients with WMA and excellent 2D echo images the correlation between echocardiographic and angiographic values was r = 0.76 for method A and r = 0.92 for method B. Method B was also tested in a group of 25 consecutive unselected patients with left ventricular WMA; in this group the correlation with angiographic values of E.F. was r = 0.84. IN CONCLUSION: in patients with WMA method B must be preferred because it is easier to perform and presents a better correlation with angiographic data than method A.

Adult↗
PubMed1985

[Efficacy and duration of action of isosorbide-5-mononitrate in the treatment of stable angina of effort. Comparison with sustained-release isosorbide dinitrate].

A new compound, Isosorbide-5-mononitrate (IS-5-MN; 40 mg orally), was compared with sustained-release Isosorbide dinitrate (SRDI; 40 mg orally) in 18 patients with chronic exercise-induced angina pectoris. The patients were studied in a randomized placebo-controlled single-blind trial. Multistage bicycle test with computer-assisted electrocardiographic analysis was performed before, 60-90, 240 and 360 minutes after treatment administration. Both drugs significantly and comparably prolonged exercise time (p less than 0.01) and time to development of 1 mm ST-segment depression (p less than 0.01) at the 3 times of study. At the highest common level of work, ST-segment depression and its integral were significantly reduced by both IS-5-MN and SRDI compared to placebo (p less than 0.01); conversely, the peak ST-segment depression was unaffected. Compared to placebo, a significant increment in maximal heart rate/systolic blood pressure was observed after drug administration. It is concluded that 40 mg of orally administered IS-5-MN is effective during at least 6 hours and that its therapeutic action is comparable to that of SRDI.

Adult↗