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Biomedical subjects

T Pop

Publications and source records attributed to T Pop.

At least 91 records · Page 5Linked to original sources
PubMed1984

[Repetitive ventricular response by programmed electrostimulation of the heart: frequency and clinical significance].

The induction of a repetitive ventricular response (RVR) by programmed electrical stimulation (PES) in patients with malignant ventricular arrhythmias such as ventricular tachycardia or ventricular fibrillation is associated with poor prognosis. However, the incidence and clinical significance of RVR in patients with normal hearts and in those with coronary artery disease (CAD) who do not have a history of malignant ventricular arrhythmias are unknown. In this paper, we present our views on the clinical value of PES in those patients. The incidence of RVR in patients without evidence of heart disease remains controversial. The possible reasons for the disparities between studies are due to differences in the study populations and stimulation protocols used. In 38 patients with normal hearts proven by left ventricular and coronary angiography no patient had three or more ventricular depolarizations in response to PES with single and double premature stimuli. The same stimulation protocol was used in 136 patients with coronary artery disease. The incidence of RVR greater than or equal to 3 (three or more ventricular depolarizations in response to PES) was related to the time interval to prior acute myocardial infarction and to the degree but not to the extent of left ventricular wall motion abnormalities. The relationship between spontaneous ventricular arrhythmias and those induced by PES was compared in 267 patients. Although there was some correlation between absence or presence of both types of arrhythmias, the presence of RVR greater than or equal to 3 did not predict precisely the presence of high grade ventricular arrhythmias during Holter-monitoring. The prognostic significance of RVR greater than or equal to 3 in patients with chronic stable coronary artery disease remains to be determined. However in patients with recent acute myocardial infarction it has been found that subjects at risk of sudden death (SD) can be identified by PES. We feel that until the prognostic significance of RVR is better defined its use as a basis for guiding antiarrhythmic therapy is not warranted.

Arrhythmias, Cardiac↗
PubMed1984

[Successful transvenous electric ablation of the AV conduction system in therapy-refractory atrial flutter].

The technique of closed-chest ablation of the atrioventricular (AV) conduction system was used in 3 patients (53-62 years of age) with atrial flutter not responding to medical management. A persistent third-degree AV block was induced in all patients. Moderate increases in CK and CKMB enzymes but not in Tc-pyrophosphate uptake were observed in these patients. 5 days after the procedure a permanent pacemaker was implanted in each case. We conclude that closed-chest ablation of the AV conduction system is a safe and efficient procedure in selected patients with drug-resistant supraventricular arrhythmias.

Adult↗
PubMed1983

Diagnosis of increased pulmonary blood flow by suprasternal M-mode echocardiography in atrial septal defect.

The right pulmonary artery (PA) was quantitatively assessed by suprasternal M-mode echocardiography in 25 patients in whom an atrial septal defect (ASD) was suspected clinically. In 10 patients an ASD was excluded (Group 1) and in 15 it was confirmed (Group 2). The smallest diameter of the right PA at end-diastole in Group 1 was 8.8 +/- 1.5 mm/m2 body surface area and in Group 2 14.8 +/- 3.6 mm/m2 (p less than 0.001). The greatest diameter of the right PA during systole was also much smaller in Group 1 (11.3 +/- 1.2 mm/m2) than in Group 2 (17.7 +/- 3.5 mm/m2) (p less than 0.001). The absolute and percent systolic expansion of the right PA did not differ in the 2 groups (2.7 +/- 0.5 mm [29.1 +/- 10.8%] in Group 1 and 2.9 +/- 0.8 mm [20.8 +/- 9.8%] in Group 2). No correlation was found between measured and derived echocardiographic variables of the right PA and the magnitude of the left-to-right shunt. Patients in Group 2, who had an additional pressure elevation in the PA, showed, on average, a larger right PA and a smaller percent systolic expansion. The study demonstrates characteristic alterations in the wall motion pattern of the right PA in patients with ASD, indicating increased pulmonary blood flow.

Adolescent↗
PubMed1983

[Diagnosis of thoracic aortic aneurysms with 2-dimensional echography].

Eight patients with thoracic aortic aneurysms were investigated by angiography, computed tomography and two-dimensional echography. According to results of computed tomography or angiography six patients had a dissecting aortic aneurysm (five patients type 1 and one patient type 3 according to DeBakey) and two patients had a thoracic aortic aneurysm without dissection. In addition, thrombi in the descending aorta were shown in three patients by computed tomography or by angiography. Type and extent of the aneurysms could be evaluated by two-dimensional echography in all patients. Only in one patient could the origin of dissection in the ascending aorta not be localised precisely by echography. In three patients thrombi in the descending aorta could be demonstrated. For assessment of type and extent of the aneurysm the suprasternal approach was superior to precordial, subcostal and apical imaging. Parasternal investigation resulted in echographic demonstration of dissection in only two cases. Two-dimensional echography is a technically less demanding and useful method in the diagnosis of thoracic aortic aneurysms.

Adolescent↗
PubMed1983

Effect of intravenous flecainide on atrial vulnerability in man.

Sixteen patients were investigated by means of programmed atrial stimulation at two different driving rates: 100 and 120/min. All patients had an increased atrial vulnerability at both driving rates. After intravenous flecainide application (1 mg/kg body weight as a bolus followed by the same amount given by infusion over a period of 20 min) the increased vulnerability was abolished in 11 and 9 patients respectively. In the remaining patients the rate of induced atrial tachyarrhythmia decreased. These findings correlate with a significant prolongation of the effective refractory period of the right atrium and a significant shortening of the relative refractory period of the right atrium. It is concluded that flecainide may be effective in the treatment of atrial arrhythmias in man.

Adolescent↗
PubMed1983

Influence of digoxin on sinus node function after pharmacologic autonomic blockade.

The effect of iv digoxin on normal sinus node function was studied after pharmacologic autonomic blockade (AB) in ten patients. Sinus cycle length (SCL), sinus node recovery time (SNRT) and sinoatrial conduction time (SACT) were determined before and after AB with propranolol (0.2 mg/kg body weight) and atropine sulfate (0.04 mg/kg body weight) iv, and 15 min, 30 min, and 45 min after 1 mg iv digoxin. AB resulted in a significant decrease (P less than 0.01) in SCL (916 +/- 158 to 716 +/- 120 ms), in SNRT (1,229 +/- 221 to 871 +/- 190 ms), and in SACT (79 +/- 34 to 44 +/- 10 ms). Fifteen minutes after iv digoxin there was no significant change observed in SCL (716 +/- 120 to 708 +/- 92 ms), in SNRT (871 +/- 190 to 864 +/- 148 ms), or in SACT (44 +/- 10 to 46 +/- 15 ms). Similar results were obtained 30 min after digoxin administration. It is concluded that a single therapeutic dose of digoxin has no direct effect on electrophysiologic parameters of normal intrinsic sinus node function.

Adult↗
PubMed1983

[Closed intracardiac cardioversion in therapy resistant atrial flutter].

Cardiac frequency could not be lowered in a 62-year-old patient with atrial flutter and 2:1 conduction. Using an electrode catheter positioned in the His bundle area an electric current of 80 Ws was effected. A third-degree atrioventricular block developed which regressed after 6 hours. The electrophysiologic assessment after one week showed a marked diminution of AV node conduction capacity.

Acetyldigoxins↗
PubMed1983

[Arrhythmias in subjects with a healthy heart].

Of 350 patients who had extensive non-invasive and invasive cardiological diagnostic tests, 56 had completely normal results. 24-hour ECG monitoring of the latter revealed the following ventricular arrhythmias-ventricular extrasystoles (VES): 36% without, 23% with rare ones (less than 30/h), 5.4% with more than 30/h, 25% with polytopic VES, 7.1% with paired VES and 3.6% with ventricular tachycardia. There was no preferential VES pattern. Mean duration of VES was 0.15 s. There were no VES with a prematurity index of less than 1. Extending ECG monitoring to 96 hours (10 persons without heart disease) did not reveal any more significant VES, but registering for less than 24 hours definitely underestimated the frequency of VES in persons without heart disease. In those without angiographic evidence of heart disease 36% had complex and 5.4% frequent VES. Complex arrhythmias, however, are rare in the individual subject and generally not accompanied by frequent VES. Frequent complex arrhythmias or both frequent and complex arrhythmias, as well as VES with a prematurity index less than 1, are suggestive of organic heart disease.

Adult↗
PubMed1983

[Incidence and clinical significance of ventricular arrhythmias in dilated cardiomyopathy].

The diagnosis of dilated (congestive) cardiomyopathy was made in 75 patients on the basis of clinical, ECG, echo and angiographic-haemodynamic findings. Ambulatory 24-hour monitoring was undertaken in all patients. Nearly all of them (93%) had ventricular extrasystoles (VES), 35% more often than 1000/24 h. In 15% VES occurred in pairs, in 44% as ventricular tachycardia. In general, frequent VES (greater than 30/h) also came in pairs and/or as ventricular tachycardia. On the other hand, not all patients with such complex arrhythmias also had frequent VES. In about 70% of all patients with ventricular tachycardia such episodes were registered repeatedly, in more than 40% more than five tachycardia episodes per 24 hours. In the majority of patients the tachycardia consisted of three (33%), four (12%) or five (18%) consecutive ventricular complexes. All episodes of ventricular tachycardia ended spontaneously and were clinically largely silent. Apparently there was no clinically relevant correlation between frequency and severity of the arrhythmia, on the one hand, and extent of abnormal ventricular function, on the other. These findings indicate that frequent and complex ventricular arrhythmias are a characteristic feature of dilated (congestive) cardiomyopathy. If they occur in heart disease of seemingly unknown aetiology, dilated cardiomyopathy should be suspected. Preliminary findings of long-term observation indicate that patients with frequent ventricular tachycardias have a higher risk of sudden death.

Adolescent↗
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

Alinidine in angina.

Alinidine--N-allyl-clonidine--reduces heart rate without blocking beta adrenoreceptors. It may be used in patients with angina without inducing the adverse effects of beta-adrenergic blockers. We therefore evaluated alinidine efficacy in patients with angiographically proven coronary artery disease and stable angina during a 10-wk placebo-controlled randomized double-blind trial. Alinidine (40 mg three times a day) reduced the number of anginal attacks and the average number of nitroglycerine capsules consumed. The double product was slightly lowered during rest but more pronounced during exercise. This effect was mainly due to decreased heart rate. The ischemic S-T segment depression was diminished. Exercise tolerance was clearly improved in six, slightly improved in two, and unchanged in four subjects.

Adult↗
PubMed1983

Improved ischemic tolerance during percutaneous transluminal coronary angioplasty by intracoronary injection of nitroglycerin.

Intracoronary injection of nitroglycerin increases ischemic tolerance in 70% of patients with unstable angina during PTCA, thus delaying development of angina pectoris and/or ventricular arrhythmias. Intracoronary injection of nitroglycerin thus seems to be a suitable way of prolonging dilation time in PTCA, an important factor of success rate. Combination with calcium-antagonists may be more effective than injection of nitroglycerin alone.

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↗