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Biomedical subjects

P Rizzon

Publications and source records attributed to P Rizzon.

At least 181 records · Page 10Linked to original sources
PubMed1987

Ventricular fibrillation induced by transesophageal atrial pacing in hypertrophic cardiomyopathy.

Sudden death is a rather frequent occurrence in patients with hypertrophic cardiomyopathy, yet the mechanism is uncertain in most cases. We describe a case of an 18 years old patient with a family history of hypertrophic cardiomyopathy and sudden death in whom ventricular fibrillation could be repeatedly induced by means of transesophageal atrial stimulation with 1:1 AV conduction at a rate of 200 beats min-1 and prevented by pharmacological depression of AV node. The not particularly high ventricular rate at which VF occurred could suggest that in hypertrophic cardiomyopathy a major role in favouring VF induction is played by the electrophysiological properties of the myocardium and that sudden death can occur as a consequence of different atrial tachyarrhythmias.

Adolescent↗
PubMed1987

Color Doppler evaluation of aortic dissection.

Color Doppler studies were performed in 16 adult patients with proven DeBakey type I and III aortic dissection. Simultaneous opacification of both aortic lumina with oppositely directed flow was noted by color Doppler in at least one aortic segment in 14 of 16 patients (12 type I, two type III). In two patients (one type I, one type III), flow was seen in one lumen only, with clot demonstrated in the other lumen in one of them. Of 12 patients in whom communication between two aortic dissection channels was shown by angiography/surgery, color Doppler correctly identified them in nine patients (four ascending aorta, two aortic arch, and three descending aorta), either by direct visualization of flow moving from one lumen into the other (six patients) or indirectly by analyzing differences in timing of opacification of the two lumina and flow direction (three patients). Also, color Doppler correctly diagnosed aortic regurgitation as severe (aortic regurgitation jet occupying more than 75% of left ventricular outflow) in three patients and moderate in four patients. Color Doppler provides comprehensive evaluation of flow dynamics in aortic dissection.

Adult↗
PubMed1986

Comparison of postexercise and transesophageal atrial pacing two-dimensional echocardiography for detection of coronary artery disease.

Two-dimensional (2-D) echocardiography during transesophageal atrial pacing (TAP) was recently proposed as an alternative to exercise 2-D echocardiography for the diagnosis of coronary artery disease (CAD). To compare these 2 methods, 78 consecutive patients with good-quality echocardiographic (echo) examinations at rest were studied. Two-dimensional echocardiography was performed immediately after supine bicycle exercise and at peak atrial pacing obtained with transesophageal atrial stimulation. Twenty patients were excluded: 16 because of poor quality of 2-D echo images after exercise and 4 because of inadequate TAP studies (atrial capture not achieved in 2 and intolerance in 2). Of the remaining 58 patients, 39 had significant CAD (at least 75% diameter stenosis of at least 1 major coronary artery) and 19 had no significant CAD. The 2 test responses were considered positive if a wall motion abnormality was detected during pacing or after exercise. Sensitivity and specificity were 82% and 95% after exercise and 90% and 84% during TAP. In patients with significant CAD but without wall motion abnormalities at rest, sensitivity was 75% during pacing and 56% after exercise. In patients with significant CAD, the wall motion score index decreased significantly with both types of stress; during pacing wall motion score index was significantly lower than after exercise. Thus, 2-D echo during TAP appears to be a feasible and reliable alternative to postexercise echo for the detection of CAD.

Blood Pressure↗
PubMed1986

Atrial pacing in the detection and evaluation of coronary artery disease.

Atrial pacing has been recently re-evaluated as a stress test for the detection of coronary artery disease. This sort of stress, especially if used in conjunction with cardiac imaging techniques can be considered a reliable alternative to physical exercise. In patients with recent myocardial infarction it can be usefully and safely utilized to obtain prognostic information. In fact, patients with recent myocardial infarction and a positive electrocardiogram (decreases ST greater than or equal to 1 mm) during atrial pacing more frequently than others present subsequent major cardiac events. Limitations of traditional pacing test (invasivity, poor sensitivity of electrocardiography) can be overcome with a new test we have recently proposed: two-dimensional echocardiography during atrial pacing. We have used this new stress test to detect patients with significant coronary artery disease, to identify patients with myocardial infarction and multivessel disease and to evaluate the effect of coronary artery bypass surgery.

Cardiac Pacing, Artificial↗
PubMed1986

Randomized placebo-controlled comparative study of nifedipine, verapamil and isosorbide dinitrate in the treatment of angina at rest.

Twenty-nine patients with angina at rest took part in a randomized placebo-controlled short-term study to assess the relative effectiveness of different dosages of nifedipine (N), verapamil (V) and isosorbide dinitrate (ISDN) versus placebo and to evaluate the antianginal effects of a sustained-release preparation of ISDN (sr), of N retard form (r) and of V retard form (r). The 29 patients were divided into 3 groups: the first group of patients (10 patients, group A) was treated with N 10 mg six times daily, V 80 mg three times daily and ISDN 10 mg six times daily; the second group of patients (9 patients, group B) was treated with N 20 mg six times daily, V 120 mg four times daily and ISDN 20 mg six times daily; the third group of patients (10 patients, group C) was treated with N r 20 mg four times daily, V r 120 mg three times daily and ISDN sr 40 mg four times daily. The daily frequency of ischaemic episodes (IE) was assessed by Holter monitoring. The effect of each drug on the mean frequency of IE was compared with the placebo using a one-way analysis of variance and the Newman-Keuls test. In group A, the mean daily frequency of IE per patient was 8.1 +/- 5.9 with the placebo, 1.4 +/- 1.9 with N (P less than 0.001; -82%), 4 +/- 3.6 with V (P: NS; -50%) and 4.3 +/- 3.6 with ISDN (P: NS; -46%). In group B it was 6.4 +/- 3.4 with the placebo, 0.5 +/- 1.6 with N (P less than 0.01; -91%), 0.3 +/- 0.5 with V (P less than 0.01; -95%) and 1.2 +/- 1 with ISDN (P less than 0.01; -82%). In group C it was 10.3 +/- 8.7 with the placebo, 0.7 +/- 1.6 with N r (P less than 0.01; -93%), 1 +/- 2.5 with V r (P less than 0.01; -90%) and 5.1 +/- 7.7 with ISDN sr (P: NS; -50%). In group A a reduction of 100% in the number of recorded IEs was achieved in 5/10 patients by using N, in none by V, and in 1/10 by ISDN. In group B, in 8/9 patients by N, in 6/9 by V and in 3/9 by ISDN. In group C, in 8/10 patients by both N r and V r in 4/10 patients by ISDN sr.(ABSTRACT TRUNCATED AT 400 WORDS)

Angina Pectoris↗
PubMed1986

Hydatid cyst of the interventricular septum causing obstruction of the right ventricular outflow tract: cross-sectional echocardiographic, angiographic and pathological findings.

Cardiac echinococcal cysts rarely involve the interventricular septum; when they do, they cause symptoms mainly related to the compression of the atrio-ventricular conduction pathways. Mild obstruction of the right ventricular outflow tract has also been described in some cases. In the case reported here, an unusual large hydatid cyst located in the interventricular septum produced a marked, symptomatic obstruction of the right ventricular outflow tract (more than 100 mmHg gradient). Surgical resection of the cyst was complicated by a 'stone heart' syndrome, probably because of a severely affected right ventricle. Cross-sectional echocardiography gave the exact site and aetiology of the mass. On the basis of these non-invasive findings, early surgery should be performed on asymptomatic patients to reduce the risk of life-threatening evolutions.

Adult↗