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Biomedical subjects

K Endresen

Publications and source records attributed to K Endresen.

At least 37 records · Page 2Linked to original sources
PubMed1995

Coronary angioplasty using a low osmolar nonionic contrast medium. A retrospective angiographic and clinical evaluation.

This study was performed to investigate the occurrence of acute angiographic and clinical complications following PTCA using a low osmolar nonionic contrast medium. Five hundred consecutive PTCA procedures were analyzed retrospectively. The incidence of acute in laboratory complications during PTCA as well as complications occurring during the hospital stay 24 to 48 hours after the procedure were recorded. Occlusion of the dilated artery or a side branch was observed in 19 (3.8%) of the procedures, major dissection in 34 (6.8%), and thrombus in 14 (2.8%). One patient died, 6 (1.2%) required emergency coronary artery bypass grafting (CABG), 4 (0.8%) required an emergency PTCA, and 7 (1.4%) suffered myocardial infarction (MI). Our results show that angiographic findings of thrombus, major dissection and occlusion were serious conditions that related to the clinical complications MI, emergency CABG and re-PTCA. Patients with unstable angina were risk patients for both angiographic and clinical complications. Low rates of intraarterial thrombus formation and coronary artery occlusion indicate good angiographic technique and anticoagulant and antiplatelet medication.

Angioplasty, Balloon, Coronary↗
PubMed1993

Iodixanol in cardioangiography in patients with coronary artery disease. Tolerability, cardiac and renal effects.

Iodixanol is a new nonionic, dimeric contrast medium. With the addition of 18 mmol/l Na+ and 0.3 mmol/l Ca++ to iodixanol 320 mg I/ml a plasma-isotonic solution was obtained. The purpose was to evaluate the suitability of iodixanol for use in cardioangiography by determining the diagnostic efficacy, patient tolerability, and cardiac and renal side-effects. Initially, 14 patients with coronary artery disease were examined using iodixanol. A double-blind, randomized study was then performed in 72 patients, comparing iodixanol and iohexol. Serum and urine were sampled before the examination, and one and 2 days after. The diagnostic information was good and the number of adverse events low with iodixanol. The patients reported significantly less of a sensation of warmth following injection of iodixanol than iohexol. Our results also indicate that iodixanol 320 mg I/ml influences renal function to a lesser degree than does iohexol 350 mg I/ml. We therefore conclude that isotonic iodixanol is a safe contrast medium for use in cardioangiography.

Adult↗
PubMed1990

[Interventional therapy in coronary heart disease].

The introduction of balloon angioplasty represents the major step in modern cardiology. Today four different techniques for interventional treatment of coronary artery disease are at our disposition for classic balloon angioplasty, laser balloon, catheter atheromectomy and endovascular prosthesis make interventions in coronary artery disease more easy and reliable. However, the main problem, restenosis, which appears in one fourth of the cases, is not yet resolved. We report our experience in 1000 cases of transluminal approach to coronary artery disease.

Angioplasty, Balloon, Coronary↗
PubMed1990

Effects of propranolol on ventricular repolarization in man.

The acute effects on monophasic action potentials (MAP), QT interval, and right ventricle effective refractory period (V-ERP) of propranolol 0.2 mg.kg-1 body weight have been studied in 10 patients with coronary artery disease. The median duration of MAP at 90% repolarization (MAP90) was shortened from 238 to 228 ms at a constant paced heart rate of 100 beats.min-1, while V-ERP remained unchanged. The median ratio V-ERP/MAP90 increased from 1.00 to 1.03. The electrical restitution curves of the duration of premature action potentials, normalized to those paced at constant heart rate, were more horizontal after propranolol. Isometric handgrip shortened MAP90 from 217 to 211 ms and after propranolol similar shortening was found (215 to 209 ms), although both values were slightly lower than before beta-blockade.

Action Potentials↗
PubMed1990

Reproducibility of echocardiographic estimates of the area of stenosed aortic valves using the continuity equation.

Interobserver variability in echocardiographic estimates of the area of stenosed aortic valves was assessed in 30 consecutive patients. Using the continuity equation, two independent observers calculated the area of stenosis from separate recordings of the diameter of the aortic orifice and the velocity time integral in the left ventricular outflow tract and in the stenotic jet. No significant difference between the observers was noted for any measurement. With respect to the area of stenosis, a high correlation between the observers was found (r = 0.92, P less than 0.001) and the regression line was close to the line of identity. The 95% limits of agreement were less than +/- 0.3 cm2. No discrepancy between the observers was found in the assessment of cases for aortic stenosis less than 0.8 cm2. Regression analyses showed good interobserver agreement also for the diameter of the orifice, the velocity time integrals, and the mean pressure gradient (r greater than 0.90, P less than 0.001). The greatest variability was noted for the diameter of the aortic orifice (95% limits of agreement +/- 1.4 cm2). We conclude that echocardiography enables reproducible estimates of the orificial area of stenosed aortic valves. Changes greater than 0.3 cm2 can be detected with a confidence probability of 95%. The greatest source of error is the measurement of the diameter of the outflow tract at the basal attachments of the aortic leaflets.

Adult↗
PubMed1989

[Immediate and late complications secondary to the implantation of a coronary endoprosthesis].

The incidence of acute and late complications after coronary stenting has been studied in 95 consecutive patients. A total of 113 stents were implanted: 23 cases for acute occlusion of the dilated vessel and 72 for restenosis. After 16 months of follow-up, minor complications had occurred in 22 patients (23%). They consisted of transient occlusion of the prosthesis in 7 patients (7.3%), non-Q wave infarction in 4 patients (4.2%) and 10 hemorrhages (11%). During the following period major complications were observed in 11 patients (12%) with myocardial infarction in 7 instances and acute occlusion in 7 patients. 5 patients (5.3%) underwent coronary artery bypass graft and 6 (6.3%) died (one in-hospital death). Two deaths were related to the stent, but in the other four no definite correlation between the prosthesis and the death could be demonstrated. Restenosis at 12 months was present in 4 cases: in 3 patients (4.7%) where the stent had been implanted for restenosis and 1 (4.7%) where it had been implanted for acute occlusion. We conclude that for selected patients, coronary stenting is a promising new technique, especially for acute occlusion after PTCA; moreover, at 12 months restenosis is less frequent than after PTCA. However, technical improvement is necessary to diminish the rate of complications, particularly thrombosis and hemorrhage.

Aged↗
PubMed1989

Rate-dependent change in dispersion of repolarisation during ventricular pacing in man.

The difference between the end of monophasic action potentials recorded in the outflow tract of right ventricle and the T-wave on the surface electrocardiogram was measured as an estimate for disparity of termination of repolarisation. It was measured during right ventricular pacing at three basic cycle lengths 500, 600 and 700 msec and programmed stimulation with single extra stimuli in 15 patients with coronary arterial disease. The disparity of termination of repolarisation was rate dependent, showing increased values when stimulated at cycle length of 700 ms compared to 600 msec (P less than 0.005) and 500 ms (P less than 0.001). Premature stimulation revealed three different modes in changes of dispersion: in six patients the premature dispersion was increased at the shortest coupling intervals from the effective refractory period. It was unchanged compared to basic values in four, and in the rest of the patients the premature dispersion was reduced at the shortest coupling intervals. These results show that the dispersion of recovery of repolarisation increases at the lower stimulation frequencies. Premature dispersion is not always increased in the closest proximity to V-ERP during programmed ventricular stimulation in patients with ischemic heart disease.

Action Potentials↗
PubMed1989

Acute effects of lidocaine on repolarization and conduction in patients with coronary artery disease.

Right ventricular repolarization and refractoriness were studied during continuous infusion of lidocaine in patients with coronary artery disease. Compared with baseline the duration of monophasic action potential was shortened (p less than 0.01) at constant and premature stimulation. Early premature action potentials were less shortened (p less than 0.05). Therefore the difference between the longest and shortest action potential duration elicited 2 to 150 msec after refractoriness decreased during lidocaine infusion (p less than 0.01). The right ventricular effective refractory period was shortened similarly to the action potential duration. Lidocaine did not change the conduction of constant paced beats, whereas the more rapid conduction of the midrange premature beats was inhibited (p less than 0.01). The inhibition of premature conduction 50 to 150 msec from the right ventricular effective refractory period may be attributed to the effect of lidocaine on the rate-dependent recovery from inactivation. The effect on the restitution curve indicates that lidocaine may influence the dispersion of premature action potentials in human beings.

Action Potentials↗
PubMed1989

Electrical restitution and conduction intervals of ventricular premature beats in man: influence of heart rate.

Monophasic action potentials (MAP) were obtained from the outflow tract of the right ventricle during apical pacing in 20 patients with coronary artery disease. The electrical restitution was studied by interpolation of extrasystoles with various coupling intervals to the preceding steady-state beat at basic paced cycle lengths (CL) of 700, 600, and 500 msec. At higher frequencies the ventricular effective refractory periods (V-ERP) and duration of MAPs became shorter and the electrical restitution curves were displaced downwards (P less than 0.001). With increasing diastolic intervals preceding the extrasystole up to a maximum of 100 msec, the duration of premature MAPs increased at all frequencies. An obvious hump of the electrical restitution curve was observed at coupling intervals of 100 msec due to a later transient decrease (P less than 0.01) in duration of MAPs at the basic CL of 500 msec. No significant hump was observed at lower heart rates. Thus, a different time course of the electrical restitution was observed at various CLs. The intraventricular conduction intervals were shorter at the shorter basic CLs when compared to the 700 msec cycles (P less than 0.05). The conduction intervals were also modified by the coupling interval between the interpolated stimulus and the preceding steady-state action potential (AP). The premature beats elicited 30 msec or earlier after refractoriness were conducted more slowly at all basic cycle lengths (P less than 0.005), and those between 60 and 150 msec after the V-ERP more rapidly (P less than 0.01) than the steady-state beats. These observations have implications for the protocols used for introducing two or more frequencies during programmed stimulation in man. Furthermore, the conduction pattern in vivo cannot be interpreted from single cell studies.

Action Potentials↗
PubMed1988

Effects of disopyramide on repolarisation and intraventricular conduction in man.

Right ventricular repolarisation and refractoriness after therapeutic doses of disopyramide have been studied in 10 patients with coronary artery disease by recording monophasic action potentials (MAP) during programmed stimulation. Using 2 catheters, with the tip of one in the apex and the other in the outflow tract of right ventricle, conduction intervals for propagation of stimuli in the ventricle were also measured. Disopyramide increased the duration of MAP signals at 90% repolarisation (MAP90), the QT-interval and the right ventricular effective refractory period (V-ERP). The ratio refractoriness/action potential duration was slightly increased. Early premature action potentials were more markedly prolonged in relation to steady-state action potentials. The differences between the shortest and longest premature action potentials, however, were not changed significantly. The conduction intervals of the normal and premature paced beats were significantly prolonged. The observed effects of disopyramide on conduction and action potential duration may be of major importance for its effect on termination and slowing ventricular tachycardias. Its influence on the duration of premature action potentials in man is consistent with the results of in vitro studies.

Action Potentials↗
PubMed1987

Reproducibility of cardiac stroke volume estimated by Doppler echocardiography.

Doppler echocardiography was used to measure cardiac stroke volume in 10 patients with coronary artery disease who were treated with cardioactive drugs. Stroke volume estimates were determined at the aortic orifice by multiplying area by systolic velocity integral measured both from the suprasternal and the apical approach. Recordings were done independently by 2 experienced observers on the same day and repeated once after 1 to 21 days. Analysis of variance showed that no systematic differences were introduced by the 2 observers and Doppler approaches or by measuring on different days. The coefficient of variation between any pair of measurements in each patient was 9%. This variability is probably a result of the method or spontaneous fluctuations of the stroke volume and not of the varying recording conditions. The ultrasonic method detects day-to-day changes of cardiac stroke volume larger than 20% with a probability greater than 0.95.

Adult↗
PubMed1987

Monophasic action potentials in patients with coronary artery disease: reproducibility and electrical restitution and conduction at different stimulation rates.

Monophasic action potentials were recorded in the outflow tract of the right ventricle in patients with coronary artery disease during ventricular pacing at different basic cycle lengths and programmed stimulation. During continuous pacing (basic cycle length 600 ms) the time for 90% repolarisation (MAP90) and the QTa interval decreased exponentially during the first 1.5-2 min of pacing to 90% of control values. The reproducibility of the monophasic action potential signals and the ventricular effective refractory period were assessed as good when studied after repetitive trains of 8 beats for more than 1.5 min. The reproducibility of conduction, however, was less good. Electrical restitution of MAP90 duration of the premature beats determined at three different basic cycle lengths was different from that in single muscle preparations. The curves showed two phases with unchanged MAP90 durations despite longer coupling intervals. The first phase was close to the ventricular effective refractory period, probably because subnormal conduction left the diastolic interval constant for the earliest premature beats. This indicates that subnormal conduction may influence the premature dispersion of repolarisation.

Action Potentials↗
PubMed1987

Blood donor selection can prevent cytomegalovirus infection after open heart surgery.

Thirty-four patients without IgG antibodies against cytomegalovirus (CMV) prior to open heart surgery were studied. The patients were randomized to receive blood either from unselected donors, or from donors without detectable CMV antibodies. Fresh whole blood was mainly used. Eleven patients received CMV seronegative blood only. All had an uneventful convalescence period and remained seronegative. Ten of the 23 patients who received blood from unselected donors had typical CMV disease with the onset of symptoms in the third or fourth postoperative week, and fever lasting for two to three weeks. They all had liver enzyme release and later seroconversion against CMV. Four patients were hospitalized during this period. The incidence of symptomatic CMV infection after open heart surgery was higher than usually reported among the CMV seronegative patients. Selection of blood donors who lack antibodies against CMV may be an adequate protective measure. Avoidance of fresh blood and reduced use of blood products are presumably also of importance.

Antibodies, Viral↗
PubMed1987

Cardiac stroke volume during exercise measured by Doppler echocardiography: comparison with the thermodilution technique and evaluation of reproducibility.

Cardiac stroke volume was measured simultaneously by Doppler echocardiography and thermodilution in patients with severe coronary artery disease. One group (20 patients) was examined during supine exercise at 25 W and a second group (20 patients) during sitting exercise at 25 W and 50 W. In a third group (10 patients) the reproducibility of the non-invasive stroke volume estimate was determined during upright exercise. There was a considerable variation between results obtained with the invasive and non-invasive technique at rest and during exercise, but no systematic differences were found. Analysis of variance showed that no systematic differences between ultrasonic results were introduced by two observers or by measurements on different days. The coefficient of variation between any pairs of Doppler measurements in each patient was 6%. These findings demonstrate that the ultrasonic technique is suitable for detecting changes in stroke volume induced by low load exercise in patients with severe angina pectoris.

Adult↗
PubMed1985

Ventricular septal rupture diagnosed by simultaneous cross-sectional echocardiography and Doppler ultrasound.

Thirteen patients with intraventricular septal rupture in the course of acute myocardial infarction (AMI) have been examined with simultaneous cross-sectional echocardiography (CSE) and Doppler ultrasound. Visualization of the rupture was achieved in six patients by CSE alone. The simultaneous technique identified the rupture in all patients. Eight patients were operated upon; seven of them are still alive. We conclude that simultaneous CSE and Doppler ultrasound is a sensitive, rapid and safe technique for diagnosing ventricular septal rupture (VSR) after AMI.

Aged↗