Biomedical subjects

G Vrouchos

Publications and source records attributed to G Vrouchos.

5 recordsLinked to original sources

PubMed1998

Isoprenaline and inducibility of atrioventricular nodal re-entrant tachycardia.

OBJECTIVES: To examine the effect of isoprenaline on slow and fast pathway properties and tachycardia initiation. DESIGN: Consecutive patients, prospective study. SETTING: Referral centre for cardiology, academic hospital. PATIENTS: 24 patients suffering from common type atrioventricular nodal reentrant tachycardia (AVNRT). INTERVENTIONS: Programmed electrical stimulation and radiofrequency catheter ablation of the slow pathway. MEASUREMENTS AND MAIN RESULTS: AVNRT was induced before and after the administration of isoprenaline in nine patients (group 1), before isoprenaline only in five (group 2), and after isoprenaline only in 10 (group 3). The anterograde effective refractory period of the fast pathway was prolonged significantly during isoprenaline administration in group 1 (405 (31) v 335 (34) ms, p < 0.001) and shortened in group 2 (308 (57) v 324 (52) ms, p = 0.005). There was also significant shortening in group 3 (346 (85) v 395 (76) ms, p < 0.001). Isoprenaline administration did not result in a significant change of the anterograde effective refractory period of the slow pathway in groups 1 and 3, but eliminated slow pathway conduction in group 2. Isoprenaline significantly shortened the minimal and maximal atrial to His bundle conduction interval recording in response to each extrastimulus of the slow pathway (210 (24) v 267 (25) ms, p < 0.001 and 275 (25) v 328 (25) ms, p < 0.001, respectively) in group 1 and significantly prolonged these intervals (331 (34) v 274 (34) ms and 407 (33) v 351 (33) ms, respectively) in group 3. In all groups only minimal changes in the refractory period of the atrium occurred after isoprenaline administration. The effect of isoprenaline was also measured on the ventricular effective refractory period and on the minimal and maximal length of the ventriculoatrial (V2-A2) interval during ventricular pacing. Isoprenaline did not result in a significant change of the ventricular effective refractory period in groups 1 and 2 nor of the shortest and longest V2-A2 interval. In group 3, however, the ventricular effective refractory period and the shortest and longest V2-A2 interval shortened significantly after isoprenaline administration. CONCLUSIONS: In group 1 isoprenaline did not affect inducibility of AVNRT because it prolonged the fast pathway refractory period without affecting slow pathway conduction. In group 2 isoprenaline shortened the fast pathway refractory period and appeared to abolish slow pathway conduction. Consequently, isoprenaline prevented induction of AVNRT. In group 3 isoprenaline facilitated induction of AVNRT. This effect seemed primarily to be the result of shortening of retrograde refractoriness of the fast pathway with prolongation of slow pathway anterograde conduction and refractory period.

Adolescent↗

PubMed1995

Aborted sudden death in the Wolff-Parkinson-White syndrome.

In a population of 690 patients with Wolff-Parkinson-White (WPW) syndrome referred to our hospital from January 1979 to February 1995, 15 patients (2.2%) had an aborted sudden death out of the hospital. This retrospective study examines their clinical and electrophysiologic characteristics. Gender, accessory pathway localization, and presence of multiple accessory pathways were compared between patients with and without spontaneous ventricular fibrillation (VF). Whereas gender and the presence of multiple accessory pathways did not significantly differ between both groups, septally located pathways occurred significantly more often in the VF group. In patients with aborted sudden death, spontaneous VF was found significantly more often in men (13 of 15). VF was the first manifestation of the WPW syndrome in 8 patients. The remaining 7 patients had documented episodes of atrial fibrillation, circus movement tachycardia, or both (n = 2). Ten of the 15 patients were exercising or under emotional stress at the time of aborted sudden death. Only 1 patient had 2 accessory pathways. The location of the accessory pathway was septal (midseptal or posteroseptal) in 11 patients, left lateral in 4, and right lateral in 1).

Adolescent↗

PubMed1994

Recurrence rate after accessory pathway ablation.

OBJECTIVE: To evaluate characteristics of patients and accessory pathways as well as additional technical factors involved in the reappearance of accessory pathway conduction after successful ablation. DESIGN: Analysis of recurrences after radiofrequency ablation. SETTING: 163 consecutive patients with 167 accessory pathways. SUBJECTS: 97 men and 66 women with a mean (SD) age of 36 (14) range (11 to 75) years. RESULTS: After a mean (SD) follow up of 14 (7) range (2 to 27) months, conduction recurred in 13 out of 167 (7.8%) accessory pathways. The initial manifestation of recurrence was circus movement tachycardia in 7 patients and reappearance of delta waves on a 12 lead electrocardiogram in 6 patients. The interval to the return of accessory pathway conduction ranged from 3 hours to 90 days. Age, sex, presence of multiple accessory pathways, criteria to determine the target ablation site, number and duration of radiofrequency applications, and cumulative energy did not significantly differ between the groups with recurrence and without. Recurrence was less common with concealed accessory pathways (2/44) than with overt accessory pathways (11/110). The difference was not significant. The only variable to influence the recurrences in this study group was the location of the accessory pathway. Reappearance of conduction through right sided accessory pathways occurred significantly more often than through left sided ones (8/40 v 5/114, P = 0.01). CONCLUSION: After radiofrequency ablation the recurrence rate of accessory pathways is low and there are no predictors of the risk of reappearance of conduction apart from the right sided location of the accessory pathway.

Adolescent↗

PubMed1992

Prediction of permanent atrial sensing by preoperative esophageal atrial wave evaluation.

Atrial undersensing is a common problem in permanent atrial and dual chamber pacing. The purpose of this study was to evaluate the relationship between transesophageal atrial wave (EsAW) and right atrial endocavitary (RA). Forty-seven patients 72 +/- 9.7 years of age, with symptomatic bradyarrhythmias were studied. The EsAW was filtered with a high pass filter of 10 Hz (Arzco preamplifier-filter), using 1, 2, and 3 cm bipolar transesophageal catheters. Atrial bipolar floating 1, 2, and 3 cm electrograms from the high RA (HRA) and from the mid RA (MRA), as well as unipolar electrograms from the right auricle (RAUR) were recorded 1 day later. Comparison by paired t-test showed no significant differences between EsAW and bipolar sensing in RA, but significant differences between EsAW and RAUR (P = 0.0001). The results of the Spearman correlation coefficient for sensing (mV) for EsAW, HRA, and MRA, respectively, were: 1 cm, 1.8 +/- 0.9, 1.7 +/- 0.9, and 1.9 +/- 0.9 (z > 3.5; P < 0.0003); 2 cm, 2.2 +/- 0.9, 1.9 +/- 0.8, and 2.1 +/- 0.9 (z > 2.3; P < 0.03); 3 cm, 2.1 +/- 1, 2 +/- 0.9, and 2.2 +/- 1.0 (z > 2.9; P < 0.003); and the result for the monopolar RAUR was 3.0 +/- 1.0 (z < 1.4; P > 0.17). These findings, if confirmed in more patients, indicate that preoperative EsAW recording could be useful in estimating the quality of bipolar floating electrograms from the RA but not of unipolar RAUR.

Aged↗

PubMed1981

Relation of personality and emotional factors to myocardial ischemia, methodology and first observations.

Within the framework of a multifacet and long term research on coronary heart disease, the possible influence of psychological factors on the disease was investigated. All coronary patients admitted to the Department are examined in special sessions. The examination is concerned with the personality structure, psychiatric or psychological abnormalities regarding living conditions, emotional factors, habits, etc. The whole study is conducted in a more or less typified way. It is the purpose of this paper to describe mainly this methodology and report preliminary results from the analysis of the first 180 patients. The reported data are compared with those from a central group of 20 'normal' controls and are compared statistically.

Coronary Disease↗