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Biomedical subjects

L Storstein

Publications and source records attributed to L Storstein.

At least 19 recordsLinked to original sources
PubMed1992

Diuretics, arrhythmias and silent myocardial ischaemia in hypertensive patients.

Patients with high blood pressure have an increased risk of sudden death compared to the normotensive population. In the highest quintile of patients with systolic blood pressure above 155 mmHg, the risk of sudden death is 3.2 greater than those in the lowest quintile. Ventricular premature contractions without known coronary artery disease also increase the risk of sudden death. Other known risk factors in this regard are age, smoking, obesity and left ventricular hypertrophy. Hypertensive patients have an increased prevalence of ventricular arrhythmias which is most pronounced in those with left ventricular hypertrophy. However, a causal relationship between ventricular arrhythmias and sudden death is uncertain. Existing data do not allow any firm conclusion as to the effects of antihypertensive treatment on such arrhythmias or on the risk of sudden death. Silent ischaemia is not uncommon in patients with hypertension but, so far, no consistent relation with coronary artery disease, left ventricular hypertrophy or neurohormonal abnormalities has been demonstrated. Silent ischaemia is an independent predictor for the development of cardiac events in patients with hypertension and may be a predictor for sudden death in these patients. Ninety-two percent of patients with ventricular tachycardia (VT) and silent myocardial ischaemia can be expected to develop morbid cardiac events compared with only 37% of those who have neither VT or silent ischaemia. At present, there is no information on the influence of diuretics on silent ischaemia in hypertensive patients. It can be concluded that both ventricular arrhythmias and silent ischaemia are important and independent risk factors for cardiac events in hypertensive patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Arrhythmias, Cardiac↗
PubMed1991

Arrhythmias in heart failure--therapeutic challenges.

Electrophysiologic disorders are common at all stages of heart failure due to myocardial mechanical factors, neuroendocrine disturbances, electrolyte abnormalities, or ischemia, and also because of cardiovascular drugs. The prevalence of various forms of heart block, bradycardias, and arrhythmias in heart failure is largely unknown, as is their relationship to the etiology of the syndrome. Complex and multiform ventricular premature beats and nonsustained ventricular tachycardia are common, and their frequency is broadly related to the severity of heart failure. Supraventricular arrhythmias are also common features of the syndrome. The heart failure syndrome has an ominous prognosis. Approximately half the patients die suddenly, but the causal relationship between preexisting arrhythmias and sudden death is not known. Equally vital is knowledge of the influence of drug therapy on the arrhythmias of heart failure, but at present this is scarce and needs further study.

Arrhythmias, Cardiac↗
PubMed1991

Electrocardiographic findings according to sex in athletes and controls.

We have previously compared the electrocardiogram of 1,299 male and female students of physical education and sports with 151 age- and sex-matched sedentary controls and found that the former had lower heart rate, longer conduction times and increased voltages. The same material of 1,450 young adult subjects was split according to sex into 617 females and 833 males in order to analyze the influence of gender on the resting 12-lead electrocardiogram. We found that females had a significant higher heart rate, shortened conduction times (PQ, Q, ventricular activation time and QRS) and a prolonged repolarization time (QTc), decreased P, Q and T amplitudes as well as indices of right, septal and left hypertrophy, and ST elevation in precordial leads were lower in females than in males. These differences were highly significant with p values less than 0.0001 for almost all parameters. Sinus bradycardia was more common in men and sinus tachycardia in women. The prevalence of other rhythms and supraventricular and ventricular premature beats was low in both sexes. AV block grade I was found in 1% of females and 3% of males (p less than 0.02). Notching of R/S in V1-V2 and incomplete right bundle branch block were less common in females (p less than 0.0001). The differences in ECG parameters between the two sexes in the total material persisted also when the athletic and control groups were investigated separately. Gender seems to be highly important for most ECG parameters in the resting ECG. This points to the necessity of discussing different upper normal limits for ECG parameters according to gender.

Adult↗
PubMed1991

Electrocardiographic findings in athletic students and sedentary controls.

We have investigated resting electrocardiograms from 1,299 athletic students taken in the same laboratory during the years 1973-1982 and compared them with electrocardiograms recorded in 151 age- and sex-matched sedentary controls. Fifty-two parameters were recorded for each electrocardiogram and computerized. We found that athletic students had a significant lower heart rate, longer PQ time and a prolonged QTc compared to control subjects. Athletes had higher maximal Q amplitudes in precordial leads, higher R in V1, and higher indices of right ventricular hypertrophy (RV1 + SV5) and left ventricular hypertrophy (Sokolow-Lyon and Grant indices). Furthermore, the athletes had higher maximal ST elevation and higher maximal T wave amplitudes in precordial leads. Sinus bradycardia was more frequent in athletes. All control subjects were in sinus rhythm whereas 0.9% of the athletes had other rhythms (nodal, coronary sinus or wandering pacemaker). Athletes and control subjects did not differ significantly with regard to premature beats, atrioventricular block, bundle branch block or the Wolff-Parkinson-White pattern. We conclude that training induces significant changes in heart rate, conduction times, ST elevation. QRS and T voltage, slow rhythm disturbances and atrioventricular and sinoatrial block were infrequent in the resting electrocardiogram taken in the supine position and disappeared immediately on sitting and during exercise. Training-induced electrocardiographic changes may partly be due to alterations in autonomic tone and partly to structural changes in the myocardium. Different normal criteria for left ventricular hypertrophy may be warranted in athletes.

Adolescent↗
PubMed1991

Cardiac arrhythmias in patients with small cell lung cancer and cardiac disease before, during and after doxorubicin administration. An evaluation of acute cardiotoxicity by continuous 24-hour Holter monitoring.

Cardiac arrhythmias have been reported during doxorubicin infusion. The aim of the present study was to investigate the prevalence of arrhythmias and elucidate whether previous cardiac disease might increase the probability of treatment-related ectopic activity. In 18 patients with small cell lung cancer, 11 with concomitant heart disease, electrocardiogram (ECG) was continuously registered by a portable tape recorder 24 h before, during and 24 h after doxorubicin infusion (Holter monitoring). The only significant finding was an increased number of bigeminal ventricular extrasystoles after doxorubicin infusion. A trend of increased number of ventricular extrasystoles was also observed. The study suggests that pretreatment arrhythmias do not dispose for increased cardiac irritability and that bolus injections of doxorubicin do not seriously influence the ectopic activity in patients with and without heart disease.

Adult↗
PubMed1990

Effect of ibopamine, a dopamine congener, on arrhythmias in heart failure.

Patients with heart failure exhibit a high prevalence of both ventricular and supraventricular arrhythmias, and the ventricular arrhythmias are characterized by multiform, bigeminal and paired beats as well as nonsustained ventricular tachycardia. The prognosis of heart failure is severe and approximately half of the patients die suddenly. In view of the high prevalence of arrhythmias in heart failure and the complex ventricular arrhythmias, it is important to consider the effect of antifailure treatment on such arrhythmias. Dopaminergic drugs represent one interesting therapeutic alternative. Ibopamine is an orally active dopaminergic substance and acts mainly as a vasodilator in patients with heart failure. According to published investigations on ibopamine in heart failure, this drug does not seem to have a proarrhythmic effect.

Animals↗
PubMed1990

Comparison between theophylline and an adenosine non-blocking xanthine in acute asthma.

Enprofylline, a drug without adenosine antagonism and theophylline, a potent adenosine antagonist, were compared, double-blind, randomized, in acute asthma (n = 33). The drugs were given intravenously as loading over 10 min followed by maintenance infusion for 24 h. Mean final plasma levels were very high with enprofylline (14 mg.l), and larger than calculated with theophylline (16 mg.l). Seven patients had maximum levels of enprofylline ranging between 16 and 42 mg.l. Extreme plasma levels of enprofylline were not associated with any theophylline-like central nervous system excitatory effects related to seizure-inducing ability. Some irregularities in the heart rhythm did not raise clinical problems and no significant difference between enprofylline and theophylline was recorded. At 1 h patients on enprofylline (mean plasma level: 5.7 mg.l) and theophylline (12.2 mg.l) had improved their peak expiratory flow rates by 31% and 15% (p less than 0.05), respectively. The improvement in lung function after 24 hours did not differ between treatments suggesting that the high levels of enprofylline were supramaximal for its anti-asthma effects in this situation. In conclusion, with enprofylline it is demonstrated that an adenosine non-blocking xanthine derivative may lack CNS-excitatory effects, but be more potent than theophylline in the treatment of acute asthma.

Acute Disease↗
PubMed1989

Electrophysiological alterations in heart failure.

Electrophysiological defects are common and diverse features of heart failure. Cardiac arrhythmias may be precipitated by mechanical factors, catecholamine release, ischaemia drug therapy or drug-induced hypokalaemia. There is a high prevalence of ventricular and supraventricular arrhythmias, and chronic atrial fibrillation is also common. Ventricular arrhythmias are characterized by multiform, bigeminal and paired beats. There is also a high incidence of non-sustained ventricular tachycardia. These abnormalities are particularly prevalent amongst patients in New York Heart Association (NYHA) functional class IV. Although the presence of complex ventricular arrhythmias and non-sustained ventricular tachycardia are regarded as prognostic markers, their role in the initiation of sudden death has yet to be proven. The results of a recent placebo-controlled clinical trial have indicated that combined therapy with isosorbide dinitrate and hydralazine can reduce mortality due to sudden death or pump failure, and is superior in this respect to prazosin. In another key study, enalapril was superior to placebo at lowering mortality caused by pump failure, but did not reduce the incidence of sudden death. These findings point to new directions of investigation which might clarify the importance of arrhythmias in heart failure, and reveal improved ways of controlling cardiac rhythm and improving prognosis.

Arrhythmias, Cardiac↗
PubMed1989

Digitoxin in patients with hepatorenal insufficiency after repeated oral administration.

Following chronic oral administration of digitoxin 0.1 mg day-1 the pharmacokinetics of this glycoside were studied in seven patients with hepatorenal insufficiency and were compared with those of seven healthy volunteers. Liver cirrhosis of the patients was confirmed by liver biopsy. Mean creatinine clearance of the healthy subjects was 129.7 +/- 3.3 ml min-1 (mean +/- SEM), that of the patients was 25.6 +/- 20.4 ml min-1. Mean antipyrine clearance (parameter of oxidative liver function) was 49.7 +/- 6.0 ml min-1 in the volunteers and 22.0 +/- 2.9 ml min-1 in the patients. Plasma protein binding of digitoxin (PPB) was 95.0 +/- 1.1% in the patients and 96.7 +/- 0.6% in the healthy subjects (n.s.). Total body clearance of digitoxin (Cltot) was 0.0728 +/- 0.0120 ml min-1 kg-1 in the patients and 0.0615 +/- 0.0027 ml min-1 kg-1 in normals (n.s.]. Mean steady state plasma levels (Css) of the patients were 18.3 +/- 4.7 ng ml-1 and 15.8 +/- 1.3 ng ml-1 in the normals (n.s.). Our data obtained from chronic oral administration do not indicate a reduced total body clearance of digitoxin in patients with hepatorenal insufficiency.

Administration, Oral↗
PubMed1988

Benzodiazepine-receptor antagonist, a clinical double blind study.

In a double blind study including 18 patients in whom a benzodiazepine intoxication was suspected, the first specific benzodiazepine antagonist was compared to placebo. There was a highly significant effect on consciousness, all patients given antagonist awaked, usually within minutes. No adverse effects were observed. In 2 patients the clinical condition deteriorated 1 to 2 hrs after the antagonist was given. This might endanger intoxicated patients withdrawing from medical attention.

Adult↗
PubMed1988

Non-receptor-mediated inotropic drugs.

There has been an active search recently for non-glycoside, non-sympathomimetic positive inotropic agents. Phosphodiesterase inhibitors inhibit the breakdown of cyclic AMP, leading to an increase in intracellular cAMP concentration, and can be expected to enhance the force of myocardial contraction. The methylxanthines exert such an action in vitro; the situation in vivo is more complex, due to their manyfold actions. Phosphodiesterase F-III is relatively specific for cAMP degradation; the new phosphodiesterase inhibitors may act specifically by inhibiting this enzyme. Phosphodiesterase inhibitors with combined inotropic and vasodilatory action include amrinone, which is no longer in widespread use due to its pronounced side-effects, milrinone, which is much better tolerated and has shown promising results in recent large-scale trials, and sulmazole which has been withdrawn due to toxic effects in rodents. Other drugs are still under investigation. Of importance is the relative role of the inotropic versus dilatory action of these drugs. A salutory effect on resting haemodynamics, does not necessarily imply improved exercise haemodynamics. The pharmacokinetic profile of these drugs is also of interest. The clinical benefits should be sustained and the side-effects should not outweigh the beneficial actions of these drugs.

Calcium Channel Agonists↗
PubMed1987

How should changes in life-style be measured in cardiovascular disease?

Traditionally, assessment of therapy has been judged by the ability of treatment to alleviate symptoms with tolerable side effects or toxicity. In recent years, it has become obvious that more subtle and patient-oriented approaches are urgently needed to evaluate progression of cardiovascular disease and to monitor the efficacy of medical and surgical therapy. Aspects of well-being include physical, emotional, and social status in cardiovascular diseases. While several major assessment methods are available within the social sciences, experiences with the use of comprehensive questionnaires in cardiovascular diseases remains relatively limited. Self-administered questionnaires have been shown to be more reliable than those given by a trained interviewer. Two forms of questionnaires--the visual analogue scale and the one in which patients check off boxes--can be used to quantify symptoms, but the former necessitates more time spent on patient information. Measurements of quality of life can be characterized by the test's validity, reproducibility, and sensitivity. Our information on the sensitivity of life-quality tests is so far scarce, but it has recently been shown that it is possible to discern the effect of various drug treatments in hypertension. The methodology of this assessment needs to be further optimized, and the quality of life parameters need to be correlated with hemodynamics, exercise capacity, morbidity, and mortality.

Cardiovascular Diseases↗
PubMed1986

Instant and sustained-release verapamil in the treatment of essential hypertension.

In a series of controlled studies for periods of 4 to 6 weeks comprising 103 patients altogether, and in 1 long-term trial for 1 year, various dosages of instant and sustained-release verapamil were administered in the treatment of mild and moderate essential hypertension. One of these trials was a double-blind comparison with nifedipine, in which the 2 calcium antagonists had an equally good effect on blood pressure. A significant blood pressure reduction was achieved with verapamil both at rest and during isometric work in most patients. About 10% of the patients were nonresponders. Pharmacokinetic studies demonstrated great interindividual variations in plasma concentrations of verapamil and its active metabolite norverapamil. Except for 1 study, no significant correlation was found between drug concentration and blood pressure reduction. All formulations of verapamil were well tolerated by the patients, and adverse effects were generally mild and often transient. No negative metabolic effects were observed during long-term treatment; serum lipids, in particular, were unaffected. PQ intervals on the electrocardiogram were significantly but moderately prolonged. QRS and QT intervals were unchanged. No increase in body weight occurred. It is concluded that verapamil is an efficacious, safe drug and a first-line treatment alternative in mild and moderate essential hypertension. The recently developed sustained formulation of the drug renders a simple dosage regimen possible.

Adult↗
PubMed1986

Which patients for secondary prevention with calcium-antagonists?

Experimental studies have shown that calcium antagonists are beneficial in reducing myocardial damage following induced infarction and thus substantiate the concept that these drugs may influence reinfarction rate and death following myocardial infarction in man. Multicenter studies with verapamil and nifedipine are in progress but without conclusive results as yet. Which patients--if any--should receive calcium antagonists for secondary prevention after myocardial infarction remains an open question. The answer will depend on whether calcium antagonists are greater, equal or less effective than beta blockers for this purpose. If calcium antagonists should prove more efficacious than beta blockers, it would seem reasonable to give calcium antagonists preference for secondary prevention in those patients where contraindications to these drugs do not exist. If however, beta blockers prove the better alternative, they should be given preference unless beta blockers are contraindicated. The complex question of the future role of drugs in secondary prevention after myocardial infarction is by far not clarified and socioeconomic consequences as well as quality of life will have to be considered in context with drug influence on survival.

Adrenergic beta-Antagonists↗
PubMed1986

Studies on verapamil in the treatment of essential hypertension: a review.

Various doses of verapamil, using the conventional and sustained release formulations, have been administered for the treatment of mild or moderate hypertension in different controlled studies for periods of 4-6 weeks, involving a total of 103 patients, and in one long-term trial for 1 year in 12 patients. A double-blind comparison of verapamil and nifedipine showed that the two calcium antagonists had equal antihypertensive action. A significant blood pressure (BP) reduction was achieved with verapamil both at rest and during isometric exercise in the great majority of patients. No significant correlation was found between age and BP reduction, but pretreatment BP and pressure reduction correlated positively. Heart rate (HR) was moderately but significantly reduced by verapamil. The established wide interindividual differences in verapamil pharmacokinetics were confirmed. There was no significant correlation between plasma drug concentrations and BP reduction, but the dosage regimens with the highest mean plasma drug concentrations were associated with the greatest mean reduction in BP. A moderate, but significant, prolongation of AV-conduction was demonstrated. QRS- and QT-intervals were unaffected. Side-effects, with all formulations of verapamil, were generally mild and often transient. No significant haematological or metabolic effects were observed during long-term treatment. It is concluded that the calcium antagonist verapamil is an effective and safe drug. It can be considered as an alternative drug in mild and moderate essential hypertension.

Delayed-Action Preparations↗
PubMed1986

Verapamil effects on left ventricular performance in patients with congestive heart failure studied with echocardiography before and after cardiac surgery.

Cardiac effects of a single dose of verapamil was studied with digitalization of M-mode echocardiograms in 6 patients before and after surgery, along with pharmacological examinations. Corresponding to the different distribution volume and excretion pre- and postoperatively, the cardiodepressive effect on the contraction of the left ventricle was more pronounced and lasted longer postoperatively. Probably due to initial reduction of peripheral resistance, there was an initial improvement of ventricular contractility indices. Obviously depending on serum concentration, maximal cardiodepression occurred at 35-40 ng/ml, and no effect could longer be found as the values reached 20 ng/ml, pre- as well as postoperatively.

Adult↗