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Biomedical subjects

R Nordlander

Publications and source records attributed to R Nordlander.

At least 91 records · Page 5Linked to original sources
PubMed1987

Ergonovine testing in patients with exertional angina.

Injection of ergonovine has been suggested as a diagnostic test in patients with suspicion of a vasospastic component in the pathophysiology of angina pectoris. However, a thorough case history has been considered by others to give the same information regarding the anginal mechanism. Therefore a bedside ergonovine test (0.075-0.675 mg i.v.) was performed in 21 consecutive patients with effort angina in order to study the relation between the outcome of the test and the case history concerning angina at rest. A coronary angiography was performed in all cases and showed significant stenoses in 17 patients and normal coronary arteries in 4. Eight patients had angina only during effort, 11 had angina both during effort and at rest and 2 patients had atypical chest pain. Ten of the 11 patients with concomitant rest angina developed chest pain at the ergonovine test and 9 coexisting ECG changes. However, these effects were about as common among the 8 patients without angina at rest: 7 developed chest pain and 4 also ECG changes. The two patients with atypical chest pain had normal coronary angiograms and in these patients ergonovine provoked the same atypical chest pain but no ECG changes. Thus, a concomitant angina at rest is a common finding among patients with severe effort angina. However, the response to ergonovine was as common in the group with only effort angina as in the group with concomitant rest angina, indicating the limited value of this test in patients with severe angina.

Adult↗
PubMed1987

Prognosis and clinical follow-up of patients resuscitated from out-of hospital cardiac arrest.

A new organization has been formed in which ambulance personnel have been trained to recognize ventricular tachycardia and ventricular fibrillation (VF) and to defibrillate. Cardiac arrest (CA) occurred in 307 patients and 140 were defibrillated. Twenty-eight patients were resuscitated and admitted for further hospital care. A previous history of ischaemic heart disease was found in 24 patients. Twenty-two of the patients admitted were found to have VF, two asystole and four other rhythms. All 11 survivors regained circulation at the site of the CA. At the time of admission all but one of the patients were unconscious and one long-time survivor remained unconscious until the 5th day following admission. Seventeen patients died while still in hospital. In 16 cases a diagnosis of acute myocardial infarction was established, a further six had VF without evidence of acute myocardial infarction and six had other diagnoses. Ten out of the 11 survivors were still alive six months after discharge. Only one case of recurrent VF was seen during a median follow-up period of 16 months. Prolonged coma, especially in combination with convulsions, was associated with a poor prognosis, while early return of circulation was significantly more common among survivors. Ongoing medication with beta-blockers, a high QRS rate on admission and VF without proof of any acute myocardial infarction were also found to be more common in survivors.

Adult↗
PubMed1987

Myocardial demands of atrial-triggered versus fixed-rate ventricular pacing in patients with complete heart block.

Hemodynamics, myocardial oxygen consumption, and lactate concentration were determined by cardiac catheterization at rest and during exercise in eight patients treated with AV universal pacemakers (DDD) for high degree AV block. The pulse generator was alternately programmed in ventricular inhibited (VVI) or atrial synchronous (VAT) mode. During VVI pacing, the cardiac output rose between rest and exercise (4.3-7.6 L/min) due to increased stroke volume. VAT pacing gave significantly greater increase (4.5-8.8 L/min) which, as the stroke volume was unchanged, resulted from accelerated heart rate. The myocardial oxygen consumption and the coronary blood flow did not differ between VVI and VAT mode at rest or during exercise, nor did the modes make a difference in arterial systolic and pulmonary wedge pressures. These observations suggested that VAT pacing offers higher cardiac output than VVI pacing, but with similar demands on myocardial oxygen consumption.

Aged↗
PubMed1987

Mononitrates as monotherapy in the prophylactic treatment of angina pectoris.

This article reviews the results of double-blind comparative studies on the therapeutic use of isosorbide 5-mononitrate as monotherapy in the prophylaxis of angina pectoris. Isosorbide 5-mononitrate appears at least as effective as the same dosage of isosorbide dinitrate and is probably superior to the calcium antagonists. Recent data have shown that isosorbide 5-mononitrate in a controlled-release formulation given once daily has a significantly better antianginal effect than placebo without inducing the development of tolerance.

Angina Pectoris↗
PubMed1987

Use of nitrates in the treatment of unstable and variant angina.

Unstable angina is a clinical syndrome that includes patients with new onset of angina, a change in a previous stable pattern, or the development of chest pain at rest. Generally, more than 90% of patients with this syndrome have significant fixed atherosclerotic coronary artery disease. Other complex, interacting pathophysiological mechanisms may include coronary vasoconstriction, plaque rupture and thrombosis. Therapeutic strategies aim at either reduction of myocardial oxygen demand or restoration of coronary blood flow. Both alternatives have been suggested as treatment of choice. However, as long as the pathophysiological mechanism(s) is unknown in the individual case, the treatment will mainly be empirical or based on results from clinical trials of heterogeneous groups of patients with unstable angina with probably varying aetiology. The results from such studies indicate that some strategies may be of value, but others may even be harmful in treatment of patients with this unstable syndrome. In this situation nitrates seem to be a safe drug which may be used in most forms of irrespective of the underlying pathophysiological mechanism(s).

Angina Pectoris↗
PubMed1986

The effect of isosorbide-5-mononitrate (5-ISMN) Durules on exercise tolerance in patients with exertional angina pectoris. A placebo controlled study.

Twenty-four patients with stable exercise-induced angina pectoris entered a double-blind cross-over study. Isosorbide-5-mononitrate (5-ISMN) 60 mg in a controlled release formulation (Durules) given once daily was compared with identical placebo. The exercise tolerance was determined by bicycle ergometry before and 3 h after a single dose of 5-ISMN and following one week's treatment with 5-ISMN and placebo. Nineteen patients completed the study. Exercise tolerance until the onset of chest pain and until 1 mm ST segment depression increased significantly 3 h after dose. The same increase was seen both after a single dose and the same dose under steady-state conditions. No increase was seen with placebo. The heart rate and systolic blood pressure reactions in the standing position were less pronounced 3 h after dose in steady-state than after a single dose of 5-ISMN. Headache was the only bothersome side-effect reported. The study demonstrates that 60 mg 5-ISMN in a Durules formulation given once daily has a significant anti-anginal effect and that tolerance does not develop.

Adult↗
PubMed1986

Atrial pacing in the management of sick sinus syndrome: long-term observation for conduction disturbances and supraventricular tachyarrhythmias.

Atrial pacing (AAI) in sick sinus syndrome (SSS) has been questioned because of the risk of distal conduction disturbances (DCD) and atrial tachyarrhythmias. The authors studied the incidence of clinically relevant DCD and arrhythmias in 52 SSS patients with AAI. The observation time was 25-67 (mean 48) months. Invasive electrophysiologic investigation was performed preoperatively in 29 cases and preoperative atrial pacing to Wenckebach block or to 150 ppm in 23. The preoperative investigation showed prolonged HV-time in three cases and Wenckebach block at 110 ppm in one case, while six patients had LAH-block, five RBB-block and two first degree AV-block. No further DCD developed in any of these patients. Second-degree type I AV-block developed in two patients after 2 and 19 months, respectively. One had been treated with digitalis and verapamil and was asymptomatic. The other patient, who had a low ventricular rate, experienced near-syncope. These two blocks could not be predicted from the preoperative and peroperative investigations. In five patients (10%) permanent atrial fibrillation developed during the follow-up period. The incidence of concomitant supraventricular tachyarrhythmias in the patients with the bradycardia-tachycardia syndrome appeared to be unaffected by the pacemaker treatment.

Adult↗
PubMed1986

Reduced incidence of myopotential pacemaker inhibition by abdominal generator implantation.

Myopotential inhibition during permanent pacing with unipolar leads is a well-recognized clinical problem. A study was undertaken to determine if implantation of the generator in abdominal subcutaneous tissue instead of the conventional pectoral implantation site would reduce the incidence of this inhibition. Forty patients with either an abdominal (group A, n = 20) or a pectoral (group P, n = 20) generator implantation site were subjected to a standardized protocol of muscle provocation and 24-hour ECG. Pulse generators were programmed to the lowest sensitivity level (average, 2.0 mV). Pauses exceeding the stimulation interval were analyzed. During muscle provocation 85% of the patients in group P displayed inhibition, as against 5% in group A (p less than 0.001). During 24-hour ECG, the corresponding values were 95% and 15%, respectively (p less than 0.001). We concluded that abdominal generator implantation significantly reduces the incidence of myopotential inhibition in patients with unipolar pacemaker leads.

Abdomen↗
PubMed1986

Antibiotic prophylaxis in pacemaker surgery: a prospective double blind trial with systemic administration of antibiotic versus placebo at implantation of cardiac pacemakers.

In a double blind clinical trial, 106 consecutive patients scheduled for pacemaker implantation were randomly assigned either to a systemic prophylaxis group (SPG) (to be given flucloxacillin) or to a control group who would be given a placebo (CPG). The SPG group received 2 g IV flucloxacillin 1 hour before the operation, then 1 g perorally every 8 hours for the next five days. In the CPG group, placebo infusions and tablets were given at the same schedule. There were a total of 106 patients (SPG 52, CPG 54) who met the criteria of the study. Of these, 102 patients (SPG 50, CPG 52) completed a follow-up of 7-35 months. Infection of the pacemaker system was not diagnosed in any patient in either group. Tissue fluid was drawn 24 hours postoperatively from the pacemaker pocket for culture and for determination of pocket antibiotic concentration. The mean flucloxacillin concentration of pocket fluid from 23 patients in the SPG was 7.5 micrograms/ml. The bacteriological cultures were positive in 9/32 patients in the SPG group and in 10/34 patients in the CPG group. This study suggests that antibiotic prophylaxis need not routinely be given at implantation of permanent pacemaker systems.

Cardiac Pacing, Artificial↗
PubMed1986

Nitrate tolerance in angina pectoris.

A review of the current literature concerning development of nitrate tolerance in the treatment of angina pectoris suggests that: development of nitrate tolerance is a clinical reality development of tolerance do not seem to differ for nitroglycerin, isosorbide-dinitrate or isosorbide-5-mononitrate a high nitrate dose seems to be more likely to induce tolerance a nitrate free interval during some part of the day or the night seems to restore vascular responsiveness by optimal use of different nitrate formulations the problem with development of tolerance may be reduced.

Angina Pectoris↗
PubMed1985

Incidence and management of pacemaker-related complications during dual-chamber pacing.

To evaluate the complication rate during AV universal pacing (DDD), 41 consecutive patients with complete heart block were studied and followed up for 2-30 (mean 10.8) months. The Cordis Sequicor Theta was used in 6 patients and the Siemens-Elema 674 in 35. Clinical problems related to the pacemaker treatment occurred in 12 patients (pacemaker tachycardia triggered by retrograde atrial activation in 2, atrial oversensing in 3 and undersensing in 2, ventricular oversensing in 2 and undersensing in 1). Ventricular fibrillation occurred during threshold measurement in one patient. Seven of the problems could be ascribed to the DDD mode. Four of these 7 problems could be solved by reprogramming the pacemaker. A nonprogrammable atrial refractory period in the Cordis Sequicor was found to be a limitation in patients with endless loop tachycardia. In 3 cases reoperation had to be performed. In another 3 cases there were problems with ventricular sensing which in one could be solved by reprogramming. Apart from ventricular fibrillation, which could not be ascribed to the DDD mode, there were no serious problems in the clinical management of the patients.

Adult↗
PubMed1985

Changes in Q-T and Q-aT intervals at rest and during exercise with different modes of cardiac pacing.

The influence of heart rate variation on the Q-T and Q-aT intervals (measured from the onset of the QRS to the end or the apex, respectively, of the T-wave) was studied both at rest and during exercise using different modes of pacing. The studies were made on 21 patients with high-degree atrioventricular block. In seven patients with programmable ventricular inhibited (VVI) pacemakers, an increase in pacing rate during rest produced significant shortening of both Q-T and Q-aT. During observations made at rest and during exercise in 14 patients with fixed rate VVI, atrial rate matched asynchronous (VVIm) or atrial triggered (VAT) pacing. Significant shortening of Q-T and Q-aT intervals occurred during exercise in all pacing modes, but was greatest with VVIm and VAT. The Q-T and Q-aT changes were almost parallel in all situations. For measurements made by two independent observers the coefficient of variation was lower for Q-aT than for Q-T (2.2 versus 2.5) and the correlation coefficient was higher (0.96 versus 0.93), indicating easier identification of Q-aT than of Q-T. This study indicated that changes in Q-T and in Q-aT are influenced by intrinsic factors in addition to the ventricular rate. Atrioventricular synchronization did not seem to influence these changes.

Adult↗
PubMed1984

Quinidine-induced changes in serum and skeletal muscle digoxin concentration; evidence of saturable binding of digoxin to skeletal muscle.

Eleven patients with atrial fibrillation on maintenance digoxin therapy were investigated by analysis of serum (SDC) and skeletal muscle (SMDC) digoxin concentrations before and 24 h and 2 weeks after starting quinidine treatment. After cardioversion the maintenance dose of digoxin was reduced in order to obtain the same steady-state SDC after 2 weeks, as before quinidine. SDC was increased by quinidine therapy from 1.56 to 2.40 nmol/l after 24 h. With the reduced digoxin dose SDC was 1.68 nmol/l after 2 weeks. The ratio SMDC/SDC decreased after 24 h of quinidine treatment from 35.4 to 29.0 (p less than 0.01). After 2 weeks of quinidine treatment with the reduced digoxin dose, the ratio had risen to 38.1, which did not differ significantly from the initial ratio. The present data suggest that the reduced skeletal muscle binding of digoxin during quinidine therapy is due to saturation of digoxin binding sites secondary to the increase in the total body load of digoxin at steady-state, and not to direct interference by quinidine with digoxin binding sites.

Aged↗
PubMed1984

Electrocardiographic prediction of the severity of aortic valvular stenosis.

The ECG at rest and at 4 min after a symptom-limited exercise test was studied in 52 patients who were catheterized because a significant aortic valvular stenosis was suspected. The calculated valve area ranged from 0.2 to 1.1 cm2/m2 BSA. QRS amplitude criteria did not discriminate between slight and severe stenoses but a negative or biphasic T wave in lead V6 did, especially after exercise. Thirty-three of the 37 patients with an area of less than or equal to 0.5 cm2/m2 BSA showed negative/biphasic TV6 after exercise but only 4 of the 15 with an area of greater than or equal to 0.6 cm2/m2 BSA. Thus, this criterion had a sensitivity for stenoses less than or equal to 0.5 cm2/m2 BSA of 89%, a specificity of 73% and a predictive value of a positive test of 89% (the pre-test likelihood being 71%). The left ventricular pressures measured during supine exercise in 38 patients did not correlate to the TV6 patterns after exercise.

Adult↗
PubMed1983

Cardiac effects of treatment with quinidine and digoxin, alone and in combination.

Systolic time intervals (QS2-I and LVET-I) and echocardiographically determined ejection fraction and velocity of circumferential fiber shortening were recorded in 10 healthy volunteers as measures of inotropic effect during maintenance treatment with 4 consecutive drug regimens: (1) quinidine, 1,200 mg/day; (2) digoxin, average dose 0.31 mg/day; (3) the combination of (1) and (2); and (4) digoxin alone (average dose 0.65 mg/day) to provide the same steady-state serum concentration of digoxin as during the period with combination of digoxin and quinidine. The steady-state serum concentration of digoxin during the low-dose regimen increased from 0.72 +/- 0.15 (mean +/- standard deviation [SD]) to 1.63 +/- 0.28 nmol/liter when quinidine was added. With the high dose of digoxin alone, the serum digoxin level reached 1.68 +/- 0.50 nmol/liter. Skeletal muscle digoxin concentrations during these periods were 27.7 +/- 8.3, 48.7 +/- 16.2, and 51.6 +/- 23.6 nmol/kg of dry weight, respectively. The skeletal muscle to serum concentration ratio of digoxin decreased significantly during quinidine treatment. Systolic time intervals were significantly prolonged by quinidine alone and shortened by digoxin alone, the latter effect being dose-dependent. Subtracting the effect of quinidine itself, the induced increase in digoxin level caused a significant increase in inotropic effect. When these corrected values were compared with those attained during the period with the same steady-state digoxin concentration but in the absence of quinidine, no significant differences were found. Echocardiographically measured ejection fraction and velocity of circumferential fiber shortening showed trends for similar drug effects, as did the systolic time intervals. This study, performed under steady-state conditions, demonstrates that the quinidine-induced increase in steady-state serum digoxin concentration will, with due consideration to quinidine's own pharmacodynamic properties, be accompanied by increased cardiac effects. This indicates that quinidine is not interfering with active receptor sites in the heart for digoxin.

Adult↗
PubMed1983

Rate of progression of severity of valvular aortic stenosis.

Twenty-six patients with valvular aortic stenosis were followed up for an average period of 9 years after the initial evaluation when the valvular disease had been considered too mild for surgical treatment. The valve area was 0.7-1.9 (mean 1.2) cm2 at the first study and 0.3-2.0 (mean 0.9) cm2 at the second. The mean annual decrease was about 0.1 cm2 in ten and less in the remaining patients. Advanced age and low physical working capacity at the first investigation were associated with rapid progression of the severity of the stenosis, but rapid progression was not predictable. At follow-up the combination of 1) calcifications of the valve on chest X-ray, 2) low physical working capacity and 3) negative/biphasic T wave in V6 after exercise was present in 100% of the severe stenoses (much less than 0.6 cm2) and in 10% of the mild (much greater than 1.0 cm2). The rate of progression of valvular aortic stenosis in adults is usually slow, but moderate stenoses may become severe within a few years.

Adolescent↗
PubMed1983

Serum digoxin determination in outpatients--need for standardization.

1 Blood samples were taken from 30 outpatients for serum digoxin analysis before and after 5 min-4 h of rest in the supine position. 2 The digoxin concentration increased significantly during rest and a steady-state concentration was reached after approximately 2 h of rest. 3 The mean increase in serum digoxin after 2 h of rest was 23% with a considerable range, i.e. 0-75% (0-0.6 nmol/l). 4 On the analogy of a previous finding of a decrease in serum digoxin concentration during exercise in healthy subjects ingesting digoxin, the present results suggest that everyday physical activity affects the serum digoxin concentration. Standardized rest in the supine position prior to collecting blood samples from outpatients is therefore necessary for reliable serum digoxin determinations.

Aged↗