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Biomedical subjects

D Kosinski

Publications and source records attributed to D Kosinski.

At least 19 recordsLinked to original sources
PubMed2000

Exercise-induced neurocardiogenic syncope: clinical data, pathophysiological aspects, and potential role of tilt table testing.

The evaluation of syncope occurring during exercise or occurring spontaneously in highly trained individuals presents a unique diagnostic challenge. It is of critical importance to exclude potential life-threatening disorders such as hypertrophic cardiomyopathy, long QT syndrome, right ventricular dysplasia, anomalous coronary artery distribution, valvular heart disease, myocarditis, or exercise-induced arrhythmia. This review is not directed towards identifying, treating, or determining athletic eligibility of individuals with such disorders. Rather, we endeavour to discuss the pathophysiology of exercise-induced neurocardiogenic syncope and to address the role of head upright tilt testing in evaluating syncope in athletic individuals in whom proper evaluation has excluded the presence of ischaemic heart disease or primary structural or electrical heart disease.

Electrocardiography↗
PubMed1999

Preliminary observations on the use of midodrine hydrochloride in the treatment of refractory neurocardiogenic syncope.

Recurrent episodes of neurocardiogenic syncope that occur without warning are a common cause of recurrent syncope that can be identified during head upright tilt table testing. While the use of beta blockers, theophyllines, fludrocortisone, disopyramide, and serotonin reuptake inhibitors can be useful in the prevention of episodes, some patients are either unresponsive to or poorly tolerant of these agents. We investigated the use of the peripheral alpha stimulating agent midodrine in preventing both tilt-induced and spontaneous neurocardiogenic syncope. Twenty-five patients (16 women, 9 men, mean age 30 +/- 23 years) with severe recurrent syncope and a positive head upright tilt table study (refractory to or intolerant of standard therapies) were placed on midodrine 5-10 mg orally three times per day, (two patients required 15 mg/day). Of these, twelve became asymptomatic and five had a marked reduction in symptoms. We conclude that midodrine may be an effective therapy in patients with recurrent neurocardiogenic syncope refractory to other forms of therapy.

Administration, Oral↗
PubMed1998

Cerebral syncope: loss of consciousness associated with cerebral vasoconstriction in the absence of systemic hypotension.

Transcranial Doppler (TCD) ultrasonography done during head-upright tilt induced neurocardiogenic syncope has demonstrated that cerebral vasoconstriction occurs concomitant with (or precedes) loss of consciousness. This article demonstrates evidence that cerebral blood flow changes alone (vasoconstriction), in the absence of systemic hypotension, may result in syncope. Five patients (4 men, 1 woman; mean age 41 +/- 17 years) with recurrent unexplained syncope were evaluated by use of an upright tilt table test for 45 minutes with or without an infusion of low dose isoproterenol. TCDoppler ultrasonography was used to assess middle cerebral artery systolic velocity (Vs); diastolic velocity (Vd); mean velocity (Vm); and pulsatility index (PI = Vs = Vd/Vmean). Syncope occurred in five patients during the baseline tilt and in one patient during isoproterenol infusion. During tilt induced syncope, at an average mean arterial pressure of 89 +/- 16 mmHg, TCD sonography showed a 2% +/- 10% increase in systolic velocity; a 51% +/- 27% decrease in diastolic velocity; and a 131% +/- 87% increase in pulsatility index. One patient underwent continuous electroencephalographic recording during tilt, which demonstrated diffuse slow wave activity (indicating cerebral hypoxia) at the time of syncope concomitant with the aforementioned TCD changes in the absence of systemic hypotension. These findings reflect an increase in cerebrovascular resistance secondary to arteriolar vasoconstriction distal to the insonation point of the middle cerebral artery, that occurred concomitant with loss of consciousness and in the absence of systemic hypotension. We conclude that in some individuals abnormal baroreceptor responses triggered during orthostatic stress may result in a derangement of cerebral autoregulation leading to cerebral vasoconstriction with resultant cerebral hypoxia in the absence of systemic hypotension.

Adolescent↗
PubMed1998

Catheter ablation for atrial flutter and fibrillation. An effective alternative to medical therapy.

Atrial flutter and atrial fibrillation are common arrhythmias that can be difficult to manage clinically. In many patients, these conditions are refractory to pharmacologic therapy because of drug failure or intolerance. Radiofrequency catheter ablation may be a reasonable alternative in patients with typical atrial flutter. The procedure has a high initial success rate and a low complication rate. However, recurrence after ablation is common, and a second treatment session may be needed. In selected patients with atrial fibrillation, radiofrequency ablation can be useful for rate control. However, its use in curing chronic fibrillation is still experimental. The procedure involves insertion of a pacemaker, anticoagulation therapy is still needed in most patients, and the need for antiarrhythmic medication may not be obviated.

Atrial Fibrillation↗
PubMed1998

Update on implantable cardioverter-defibrillators. New, safer devices have led to changes in indications.

The safety and efficacy of ICDs have improved significantly in the past few years. Recent evidence supports the value of these devices not only for secondary prevention of sudden cardiac death, but also for primary prevention in post-myocardial infarction patients with poor left ventricular function, unsustained ventricular tachycardia, and inducible ventricular tachycardia on electrophysiologic study. Transvenous defibrillation using the defibrillator case as the high-voltage electrode and a biphasic shock is currently the procedure of choice. Implantation is simple, and the defibrillation thresholds are acceptably low. However, the possibility of interactions must be considered in patients with cardiac pacemakers.

Arrhythmias, Cardiac↗
PubMed1997

Dysautonomic and reflex syncope syndromes.

Both dysautonomic and reflex syncope are common problems that, although related to neurocardiogenic syncope, are somewhat distinct entities. Proper diagnosis and management require an adequate knowledge of these disorders. Further investigations will continue to advance knowledge of these various disorders of orthostatic control.

Autonomic Nervous System↗
PubMed1997

Responses of normal subjects during 80 degrees head upright tilt table testing with and without low dose isoproterenol infusion.

Head upright tilt table testing has emerged as a standard technique for the evaluation of patients with recurrent unexplained syncope. To determine the specificity of head upright tilt table testing with and without a low dose isoproterenol infusion, the following study was undertaken. A total of 34 normal volunteers (21 men, 13 women, mean age 32.9 +/- 1.7 years) with no history of syncope, presyncope, or vertigo underwent head upright tilt table testing for 45 minutes. A positive test was defined as the production of syncope or presyncope associated with hypotension and bradycardia. If the test was negative the patient was lowered to the supine position and a low dose isoproterenol infusion started (sufficient to raise the heart rate 20-25% above baseline) and the patient retilted for 20 minutes. Three subjects (8.8%; 95% CI: 2, 26; P = 0.23) developed syncope during the test, two during the baseline tilt, and one during isoproterenol infusion. Interestingly, one of these subjects later had a clinical syncopal episode. We conclude that head up tilt table testing at 80 degrees with or with out low level isoproterenol infusion provides an adequate specificity.

Adult↗
PubMed1997

Tilt table testing: concepts and limitations.

Recurrent unexplained syncope is a common and often frustrating clinical problem. Over the last decade, head upright tilt table testing has emerged as an important diagnostic method for the identification of individuals whose syncope is likely to be neurocardiogenic in origin. At the same time, tilt table testing, by providing syncopal episodes in a controlled setting, has allowed for a much greater understanding of these disorders. This article reviews the concepts behind tilt table testing, as well as the uses and limitations of the evolving diagnostic modality.

Blood Pressure↗
PubMed1996

Current trends in etiology, diagnosis, and management of neurocardiogenic syncope.

Recurrent episodes of unexplained syncope are among the most frequent of complaints referred to physicians for evaluation. Traditional methods of evaluation were both time consuming and expensive and left many patients without a diagnosis. Although neurocardiogenically mediated episodes of hypotension and bradycardia were felt to be a common cause of syncope, this was traditionally a diagnosis of exclusion. The emergence of head-upright tilt-table testing has provide a valuable method for identifying individuals predisposed to neurocardiogenic syncope and has also allowed for a better understanding of this phenomena. This article reviews the pathophysiology of neurocardiogenic syncope, the use of head-upright tilt-table testing in its diagnosis, and the potential therapies used to prevent recurrences.

Animals↗
PubMed1996

The use of methylphenidate in the treatment of refractory neurocardiogenic syncope.

Recurrent neurocardiogenically mediated episodes of hypotension and bradycardia are a common cause of recurrent syncope that can be identified by head upright tilt table testing. While the use of beta-blockers, theophylline, fludrocortisone, disopyramide, and serotonin re-uptake inhibitors can be helpful in preventing further episodes, some patients are unresponsive to or poorly tolerant of these agents. We investigated the use of the central nervous system stimulant and peripheral vasoconstrictor methylphenidate in preventing both tilt induced and spontaneous neurocardiogenic syncope. Seven patients (all women, mean age 31 +/- 15 years) with recurrent syncope and positive head upright tilt induced hypotension/bradycardia (refractory to normal therapy) were placed on methylphenidate 10 mg orally three times per day. Six of the seven patients became both tilt negative and clinically asymptomatic over a 7-month follow-up period. We conclude that methylphenidate may be an effective therapy in patients with recurrent neurocardiogenic syncope refractory to other forms of therapy.

Administration, Oral↗
PubMed1995

Pathophysiological aspects of neurocardiogenic syncope: current concepts and new perspectives.

Neurocardiogenic syncope is both a common and complex clinical disorder. Although recent research has clarified some of the pathophysiological mechanisms involved, much still remains either unknown or incompletely understood. Further investigation into this condition will not only enhance our knowledge of this and other related disorders, but will shed greater light on the influences of the brain and autonomic system on heart rate and blood pressure regulation and aid in our understanding of the complex interrelationships of neurocardiology.

Blood Pressure↗
PubMed1995

Postpartum syncope.

Recurrent unexpected syncope may have severe consequences and result in serious injury. This is especially the case in the immediate postpartum period when maternal syncope may have a disastrous effect on the infant as well as the mother. We report on 12 women who developed episodic hypotension resulting in syncope in the immediate postpartum period and describe the distinguishing characteristics of their presentation, tilt table results, and responses to therapy. Postpartum syncope represents a unique subgroup of syncopal patients who need to be recognized and treated in order to prevent potentially serious injury to both mother and infant.

1-Naphthylamine↗
PubMed1994

Fluoxetine hydrochloride for the treatment of severe refractory orthostatic hypotension.

OBJECTIVE: To evaluate the usefulness of fluoxetine hydrochloride in the treatment of patients with severe refractory orthostatic hypotension. DESIGN: Prospective, nonrandomized study. PATIENTS: Five patients (3 men, 2 women with a mean age of 67 +/- 7 years with chronic symptomatic orthostatic hypotension resistant to or intolerant of other therapies. METHODS: Symptoms and orthostatic responses were recorded in the baseline state. Fluoxetine hydrochloride 20 mg orally once daily was started and patients were reevaluated after 6 to 8 weeks of therapy. RESULTS: All patients demonstrated orthostatic hypotension (20 mm Hg or greater decline in systolic blood pressure) associated with symptoms (eg, dizziness, vertigo, near syncope) in the baseline state. After 6 to 8 weeks of fluoxetine therapy, 2 patients reported resolution of all symptoms, 2 had a marked reduction in symptoms, and 1 patient experienced no effect. Orthostatic responses were attenuated in 4 of the 5 patients (80%). CONCLUSION: Fluoxetine hydrochloride may be an effective therapy for some patients with recurrent severe orthostatic hypotension refractory to other forms of therapy.

Aged↗
PubMed1994

Use of sertraline hydrochloride in the treatment of refractory neurocardiogenic syncope in children and adolescents.

OBJECTIVES: The purpose of our study was to determine whether the serotonin reuptake inhibitor sertraline hydrochloride could prevent neurocardiogenic syncope in children and adolescents resistant to or intolerant of other therapies. BACKGROUND: The serotonin reuptake inhibitor fluoxetine hydrochloride has been reported to be effective in preventing neurocardiogenic syncope in adults. METHODS: Seventeen consecutive young patients (mean age 15 years, range 10 to 18; 7 male, 10 female) with recurrent syncope and a positive head-upright tilt table test, and in whom standard therapies (fludrocortisone, transdermal scopolamine, beta-adrenergic blocking agents, disopyramide) were ineffectual, poorly tolerated or contraindicated, were referred for study. Sertraline was administered orally at 50 mg daily for 4 to 6 weeks. A head-upright tilt table test was then reperformed, and the clinical effect was noted. RESULTS: Three patients (18%, 95% confidence interval [CI] 1 to 44) were intolerant of the drug, and it was discontinued. Nine patients became asymptomatic and tilt negative (53%, 95% CI 26 to 76), and five remained tilt positive (36%, 95% CI 15 to 65). Over a mean follow-up period of 12 +/- 5 months, the tilt-negative patients remained symptom free while taking sertraline. CONCLUSIONS: The serotonin reuptake inhibitor sertraline hydrochloride can be effective in preventing recurrent neurocardiogenic syncope in selected patients unresponsive to or intolerant of other therapeutic modalities.

1-Naphthylamine↗