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Biomedical subjects

N Treese

Publications and source records attributed to N Treese.

At least 109 records · Page 6Linked to original sources
PubMed1983

Electrophysiologic effects of lorcainide on the accessory pathway in the Wolff-Parkinson-White syndrome.

The electrophysiologic effects of lorcainide, a class I antiarrhythmic agent with local anesthetic properties, were studied in 20 patients with the Wolff-Parkinson-White syndrome. After intravenous administration of lorcainide (2 mg/kg), the sinus cycle length decreased in all patients from 705 +/- 117 to 636 +/- 94 ms (p less than 0.001). The atrioventricular conduction time lengthened from 84 +/- 22 to 94 +/- 22 ms (p less than 0.01) and the QRS duration increased from 92 +/- 19 to 120 +/- 29 ms (p less than 0.001). The effective refractory period of the atrium increased from 230 +/- 27 to 243 +/- 35 ms (p less than 0.05), whereas the ventricular refractoriness was unaffected. Retrograde conduction over the accessory pathway was blocked in 5 of 18 patients after lorcainide; in the remaining 13 patients a prolongation from 107 +/- 32 to 162 +/- 57 ms (p less than 0.001) was found. Anterograde conduction over the accessory pathway was blocked in 6 patients, and in all other patients it increased considerably. Circus movement tachycardia could be induced in 14 patients before and in 10 patients after the drug. The shortest R-R interval during tachycardia lengthened from 326 +/- 40 to 364 +/- 67 ms (p less than 0.05). The tachycardia zone was unaffected by lorcainide. In 15 patients atrial fibrillation was induced. After lorcainide anterograde conduction during atrial fibrillation was blocked (n = 5). The shortest R-R interval over the accessory pathway during induced atrial fibrillation increased from 228 +/- 35 to 304 +/- 103 ms (p less than 0.05). Intravenous administration of lorcainide produced a pronounced negative dromotropic effect on the conduction properties of the accessory pathway. Lorcainide appears to be a promising new antiarrhythmic agent in patients with the Wolff-Parkinson-White syndrome.

Adolescent↗
PubMed1983

The suprasternal approach to recording aortic valve prostheses: a comparison with the precordial and subxiphoid approaches.

We evaluated 56 consecutive patients echocardiographically 9 days to 104 months after aortic valve replacement by the precordial, subxiphoid and suprasternal approach. In 11 patients, the mitral valve had also been replaced. For comparison, a subjective grading system (score 1 up to 3) was applied to the records obtained from each approach. Disc valves (n = 41) were equally scored from the precordial and suprasternal approach (score 2.6). Ball prostheses (n = 6) were best imaged from the suprasternal approach (score 3.0), whereas bioprostheses (n = 9) were best visualized from the precordial (1.8). Simultaneous imaging of both valves was possible in 6 out of 11 patients with a double prosthesis using the suprasternal approach but not from precordial and subxiphoid approaches. Six patients presented prosthetic valve dysfunction. Five patients had paravalvular insufficiency; 4 of these patients had a Björk-Shiley valve and one patient a Lillehei-Kaster valve. The echograms of 4 out of 5 patients with a paravalvular leak were normal from each approach. In another patient an obstructed Björk-Shiley prosthesis was found. The pre- and postoperative echograms demonstrated that the suprasternal approach was best to visualize the obstructed valve. The study shows that the suprasternal technique is superior for evaluation of most patients with aortic valve prostheses.

Adult↗
PubMed1983

[Beta-adrenergic stimulation with prenalterol in sick sinus syndrome].

The effect of beta-adrenergic receptor stimulation on sinus node function in patients with sick-sinus syndrome was investigated. Electrophysiological studies were performed in 14 patients (5 males and 9 females) aged 18-81 years before and after intravenous administration of 50 micrograms Prenalterol per kilogram body wt. Prenalterol decreased spontaneous cycle length by 26% (p less than 0.01), which corresponded to an increase in heart rate of 21 beats/min. The corrected sinus node recovery time was shortened by 23% (n.s.) in 10 patients, and was abnormal in 12 patients before and in 10 patients after Prenalterol. Secondary pauses occurred in 8 patients at control and in 9 patients after drug administration, in 2 of them for the first time after Prenalterol. In the sick-sinus syndrome the pronounced chronotropic response to beta-adrenergic receptor stimulation with Prenalterol doses not indicate improvement of impaired sinus node function.

Adolescent↗
PubMed1983

[Effect of nifedipine on sinus node and atrioventricular node function following autonomic blockade in the human].

The effect of intravenously administered nifedipine (7.5 micrograms/kg) on sinus node and atrioventricular (AV) node function was evaluated in 17 patients, 9 of whom had sinus node disease after autonomic blockade (propranolol 0.2 mg/kg and atropine 0.04 mg/kg i.v.). The patients' ages ranged from 18 to 77 years. After nifedipine there was a nonsignificant increase in the median values for sinus cycle length from 750 ms to 760 ms, for sinus node recovery time from 1150 ms to 1240 ms, for corrected sinus node recovery time from 440 ms to 460 ms, and for sinoatrial conduction time from 63 ms to 75 ms. Nevertheless, nifedipine produced a significant increase in the AV node refractory periods (median values): the effective refractory period lengthened from 300 ms to 305 ms (rate 100/min) and from 290 ms to 300 ms (rate 120/min) respectively. The functional refractory period increased from 380 ms to 400 ms (rate 100/min) and from 385 ms to 410 ms (rate 120/min) respectively. The Wenckebach period was significantly prolonged from 370 ms to 390 ms. We conclude, therefore, that in the absence of autonomic control intravenous administration of nifedipine exerts a mild depressive effect on AV node but not on sinus node function.

Adolescent↗
PubMed1983

[Repetitive ventricular response and left ventricular wall motion in patients with coronary heart disease].

As the first results of a prospective study on the value of programmed ventricular stimulation, the incidence of repetitive ventricular response with 3 or more consecutive beats (RVR3) in 136 patients (122 males, 14 females, age 51 +/- 8 years) with coronary artery disease is reported. 38 patients (group A) had no evidence of previous myocardial infarction, 31 patients (group B) had myocardial infarction less than 3 months and 67 patients (group C) more than 3 months before entry into the study. Programmed electrical stimulation included single (S2) and double (S2 S3) ventricular premature beats following ventricular drive at 3 cycle lengths (500, 600 and 430 msec) and was defined as positive (+PES) when RVR3 was induced. +PES was related to the extent and the degree of abnormal left ventricular wall motion, determined by left ventricular angiography (30 degrees RAO view) and quantified by a wall motion score. After single premature stimuli no RVR3 was observed in group A, but in 7% of group B and in 19% of group C (p less than 0.01). After double premature stimuli RVR3 occurred in 17% of group A, 42% of group B and 34% of group C (p less than 0.1). All 3 groups differed with respect to mean wall motion score and number of akinetic wall segments (p less than 0.001). Patients with positive (+PES) or negative (-PES) results could not be separated when the extent of wall motion abnormalities (wall motion score, number of akinetic segments) was considered. However, a relation (p less than 0.01) to the degree of abnormal wall motion classified according to the presence of normokinesis, hypokinesis, akinesis or dyskinesis could be demonstrated for +PES after single but not after double premature stimuli.

Coronary Disease↗
PubMed1983

[Separation of the left atrium from the right pulmonary artery in the suprasternal echocardiogram: a parameter of left atrial pressure].

A separation of the left atrium from the right pulmonary artery during atrial contraction may be observed in the suprasternal echocardiogram. In 280 catheterized patients with sinus rhythm, we investigated whether left atrial separation is a parameter from which an estimate of the left atrial pressure can be obtained. In 239 of the 280 patients, the suprasternal echograms were of a quality such that it could be seen whether there was, a left atrial separation. In 182 patients, a normal left atrial pressure (greater than or equal to 12 mm Hg) was found; in 57 patients, the left atrial pressure was elevated. An atrial separation was observed in 183 patients, and in 56 patients it was lacking. Lack of left atrial separation indicates a left atrial pressure elevation with a sensitivity of 73.7% and a specificity of 92.3%. If a left atrial pressure above 18 mm Hg was considered elevated, the sensitivity of this echoparameter amounted to 90.3%, and the specificity was 86.5%. The study shows that the left atrial separation from the right pulmonary artery separation from the right pulmonary artery in the suprasternal echocardiogram is a parameter valuable in providing a rough estimate of the left atrial pressure.

Blood Pressure↗
PubMed1982

[Importance of echocardiography for the assessment of left-ventricular function and cardiac complications in dilative cardiomyopathy].

One- and two-dimensional echocardiographic findings in 17 patients with dilated cardiomyopathy were compared with haemodynamic and angiographic results of cardiac catheterization. In a further 52 unselected patients with dilated cardiomyopathy, who had been seen as out- or in-patients over a period of two years, the frequency of intracardiac thrombi was investigated echocardiographically. A significant correlation (r = 0.66 and r = 0.68) was found between echocardiographically determined left-ventricular end-diastolic and end-systolic volumes on the one hand and volumes determined angiographically on the other. However, ventricular volumes were clearly underestimated by echocardiography. In contrast, both methods showed good agreement for the magnitude of the ejection fraction (r = 0.79). The aortic valve opening surface estimated with one-dimensional echocardiography correlated with left-ventricular ejection volume (r = 0.93). Thrombi were demonstrated in 7 out of 52 patients: 5 were located in the left, one in the right and a further one in the central pulmonary vascular system. Considering the aforementioned limitations, echocardiography is a useful method for evaluation of left-ventricular function and for demonstration of intracardiac thrombi in dilated cardiomyopathy.

Adolescent↗
PubMed1982

Influence of norepinephrine on vessel geometry of the intact femoral artery in juvenile insulin-dependent diabetics-evidence of early diabetic angiopathy in central arteries.

A modified M-mode ultrasound echo system had been employed to study blood-vessel geometry of the intact femoral artery before and after Norepinephrine (NE) infusion. 14 patients with juvenile IDDM aged below 35 years and 11 healthy subjects participated in the study. In the diabetic group, wall distensibility (delta D/delta P) was reduced (p less than 0.01) at control conditions. After NE infusion, wall distensibility decreased in both groups (p less than 0.01). The decrease of wall distensibility is due to an increase in pulse pressure (delta P) (p less than 0.002) in the diabetic group and a reduction of pulsatile diameter (delta D) (p less than 0.02) in the normal group. Increased stiffening of the arteriaL wall after NE infusion with progressive reduction of wall strain (delta D/Dd) is the typical finding in the normal group. No change of wall strain was observed in the diabetic group. The functional alteration of the diabetic femoral artery may be described as diminished resistance of the arterial wall to the distending force of rising blood pressure.

Adolescent↗
PubMed1982

[Transient sinus node arrest-a dysregulation of the autonomic nervous system (author's transl)].

Electrophysiologic studies had been performed before and after pharmacologic autonomic blockade (propranolol 0.2 mg/kg and atropine 0.04 mg/kg body weight) in a 23-year-old female patient with documented sinus arrest of 27 sec duration. Normal electrophysiologic findings before and after autonomic blockade excluded intrinsic sinus node dysfunction. Sinus arrest is therefore though to be due to an intermittent dysregulation of the autonomic nervous system.

Adult↗
PubMed1981

Separation of left atrium from right pulmonary artery: a new echocardiographic sign of pericardial effusion.

We report a new echocardiographic sign of pericardial effusion in patients with pericardial effusion examined by the suprasternal approach. In normal individuals the right pulmonary artery is closely connected with the superior wall of the left atrium. A separation of these structures is only to be noticed during atrial contraction. In 12 of 17 patients with a pericardial effusion observed a separation of the left atrium from the right pulmonary artery ranging from 3 to 20 mm throughout the cardial cycle. We suggest that this echo-free zone represents fluid in the transverse pericardial sinus which is located between the two structures. In five patients with a small pericardial effusion (less than 400 ml) this observation could not be made.

Diagnosis, Differential↗
PubMed1980

Undersensing of demand pacemakers in acute myocardial infarction.

Trasient asynchronous pacing due to abnormal sensing function is reported in two patients with inserted demand pacemakers during the early phase of acute myocardial infarction. The hazards of the pacemaker induced parasystole with R on T phenomenon in conditions of enhanced electrical instability could be successfully overcome applying overdrive suppression of the inserted pacing system by external chest wall stimulation.

Acute Disease↗