Search PubMed⌕ Search

Biomedical subjects

B P Grubb

Publications and source records attributed to B P Grubb.

At least 19 recordsLinked to original sources
PubMed1995

Cardiac pacing for prevention of recurrent vasovagal syncope.

PURPOSE: To review the status of cardiac pacing for the treatment of patients with recurrent vasovagal syncope. DATA SOURCES: A MEDLINE search for English- and French-language articles published between 1980 and 1994 about cardiac pacing for prevention or treatment of vasovagal syncope. The term cardiac pacing was used in conjunction with the terms vasovagal, neurally mediated, or neurocardiogenic syncope, but not with the term carotid sinus hypersensitivity. STUDY SELECTION: Case reports and series from peer-reviewed journals were selected if they documented the presence of vasovagal syncope and assessed pacing effectiveness using tilt-table testing, clinical follow-up, or both. Four case reports and four series met these criteria. DATA EXTRACTION: Findings were summarized individually. Statistical analysis of combined data was inappropriate given differences among studies in patient selection, testing, and follow-up. RESULTS: Pacing may be useful in selected patients with predominantly cardioinhibitory vasovagal responses. Pacing alone may eliminate symptoms in 25% of these patients and may prevent abrupt cardiovascular collapse in others (such as those in whom syncope occurs with minimal or no premonitory sensation). However, interpretation of most available reports has been limited both by the uncertainty associated with using the tilt-table technique to assess pacing effectiveness and by relatively short-term follow-up. CONCLUSIONS: The usefulness of cardiac pacing for patients with recurrent vasovagal syncope remains only partly understood. Randomized controlled trials are needed for this and other aspects of the treatment of this condition. Additionally, substantial room remains for innovation both in earlier recognition of imminent vasovagal syncope by implantable devices and in specifically designing cardiac pacing algorithms for treatment of this condition.

Algorithms↗
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

Cardiovascular causes of loss of consciousness in patients with presumed epilepsy: a cause of the increased sudden death rate in people with epilepsy?

UNLABELLED: BACKGROUND, METHODS, AND RESULTS: Syncope and seizures are often indistinguishable clinically. We present a series of 12 patients diagnosed as having epilepsy. Despite normal or nonspecific electroencephalographic findings, 11 of 12 patients were treated or offered treatment with long-term anticonvulsant agents. Subsequently, diagnoses of arrhythmic or neurally mediated syncope were made in all patients using Holter monitoring, long-term ambulatory loop electrocardiographic recording, or tilt-table studies. Arrhythmias included torsades de pointes (four patients), atrioventricular nodal reentrant supraventricular tachycardia (one patient), and sinus arrest (two patients). The remaining five patients had neurally mediated syncope with hypotension and bradycardia, including asystole in two patients. Treatment for the documented cardiovascular abnormalities resulted in the alleviation of syncopal symptoms. CONCLUSIONS: Because the observed cardiovascular abnormalities are potentially fatal, this series suggests that undiagnosed cardiac syncope may contribute to the documented increased sudden death rate in patients with presumed epilepsy. Cardiac causes of loss of consciousness should be considered in patients with presumed epilepsy, atypical premonitory symptoms (such as nausea, lightheadedness, or palpitations), nondiagnostic electroencephalograms, and failure to respond to anticonvulsant therapy.

Adolescent↗
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↗
PubMed1994

Neurally mediated syncope with an update on indications and usefulness of head-upright tilt table testing and pharmacologic therapy.

Neurally mediated episodes of hypotension and bradycardia (neurocardiogenic syncope) are a common cause of recurrent syncope. Clinically, these episodes may present as an isolated event with an identifiable stimulus, or manifest as a syndrome of recurrent idiopathic syncopal events. The technique of head-upright tilt table testing has emerged as a safe and effective modality to identify individuals with this disorder. The use of isoproterenol as an adjunct to tilt table testing is widely employed although controversial. Whereas the mechanism of neurally mediated syncope is incompletely understood, effective therapies are available. Multiple pharmacologic agents, either alone or in combination, have proven effective in preventing recurrent episodes. The role of cardiac pacing as therapy for a subgroup of patients who manifest severe bradycardia or asystole remains controversial as well. Additional study is necessary to further define the mechanism of neurally mediated syncope, provide new therapeutic strategies, and perhaps provide alternative diagnostic techniques.

Bradycardia↗
PubMed1994

The use of serotonin reuptake inhibitors for the treatment of recurrent syncope due to carotid sinus hypersensitivity unresponsive to dual chamber cardiac pacing.

Carotid sinus hypersensitivity can be a cause of recurrent unexplained syncope in the older patient. Dual chamber cardiac pacing may relieve the bradycardia, but may not affect the vasodilatory component of this disorder. We report on two patients with carotid sinus hypersensitivity with a predominant vasodilatory component who experienced recurrent syncope following permanent pacemaker implantation. Both patients were treated with serotonin reuptake inhibitors and after 4-6 weeks of therapy had complete resolution of symptoms. We conclude that serotonin reuptake inhibitors may be useful in the treatment of recurrent syncope due to carotid sinus hypersensitivity resistant to dual chamber cardiac pacing.

1-Naphthylamine↗
PubMed1993

Usefulness of fluoxetine hydrochloride for prevention of resistant upright tilt induced syncope.

Recurrent vasovagally mediated episodes of hypotension and bradycardia are a common cause of recurrent syncope that can be identified by head-upright tilt table testing. Although the use of beta blockers, transdermal scopolamine, disopyramide, and fludrocortisone may be helpful in preventing further episodes, some patients are intolerant of or respond poorly to each of these agents. Following anecdotal observations, we investigated the utility of fluoxetine (a serotonin re-uptake antagonist) in preventing head-upright tilt induced hypotension/bradycardia in patients unresponsive to or intolerant of standard therapy. Sixteen patients (7 men and 9 women, mean age 42 +/- 21 years) with recurrent syncope and positive head-upright tilt studies (refractory to normal therapy) were placed on fluoxetine and restudied 5-6 weeks afterward. Three patients were intolerant of the medication. Of the 13 patients who underwent repeat tilt studies, seven patients (53% of the patients retested or 44% of the total group) were rendered tilt table negative, and, over a mean follow-up period of 19 +/- 9 months, have remained asymptomatic. We conclude that fluoxetine may be an effective therapy in patients with recurrent vasovagally mediated syncope refractory to other forms of therapy.

Adult↗
PubMed1993

Adaptive rate pacing controlled by right ventricular preejection interval for severe refractory orthostatic hypotension.

A 72-year-old African-American man with frequent recurrent syncope was found to have severe refractory orthostatic hypotension with concomitant supine hypertension. Pharmacotherapy was successful in controlling his supine hypertension but was unable to resolve his severe orthostatic hypotension. Temporary fixed rate tachypacing was only minimally effective in preventing syncope during upright tilt, while variable rate pacing based on degree of blood pressure fall was far superior. Following these observations, an adaptive rate pacing system controlled by right ventricular preejection interval was implanted (Precept DR Model 1200). The system adequately sensed the patient's fall in blood pressure when sitting or standing and augmented its rate accordingly, thus preventing syncope. While supine, the pacing rate fell to 60 ppm, thereby, avoiding an exacerbation of his concomitant supine hypertension. Over a 3-month follow-up period, he has had no further orthostatic or syncopal episodes. We conclude that adaptive rate pacing using right ventricular preejection interval may be an effective treatment for severe refractory orthostatic hypotension.

Aged↗
PubMed1992

Head-upright tilt-table testing in evaluation and management of the malignant vasovagal syndrome.

Vasovagally mediated cardiac asystole has been proposed as a potential cause of sudden cardiac death. To assess this possibility and identify characteristics that define patients with vasovagally mediated asystole, head-upright tilt-table testing was performed in 50 consecutive patients (26 women and 24 men, mean age 42 +/- 10 years) with recurrent unexplained syncope. The upright tilt-table test was performed in the fasting state for 30 minutes, with or without the use of intravenous isoproterenol (1 to 3 micrograms/min). The production of ventricular asystole lasting greater than 4 seconds was considered a positive result. All patients with tilt-induced asystole received therapy with either beta blockers, disopyramide, transdermal scopolamine or atrioventricular permanent pacing, the efficacy of which was evaluated with serial tilt-table tests. Reproducible tilt-induced asystole occurred in 10 patients (7 men and 3 women, mean age 23 +/- 12 years) (7 patients during baseline tilt, and 3 during isoproterenol infusion). Analysis of this group revealed that they had significantly more frequent and severe syncopal episodes (3 patients had episodes needing bystander cardiopulmonary resuscitation) than did those patients with tilt-induced syncope without asystole. All patients who had tilt-induced asystole eventually became tilt-table negative with therapy (4 with beta blockers, 2 with disopyramide, and 4 with atrioventricular permanent pacing), and over a mean follow-up of 21 +/- 6 months no further syncopal episodes occurred. It is concluded that patients with recurrent tilt-induced asystole represent a distinct subgroup that has recurrent severe syncope that may mimic or result in sudden cardiac death. Thus, the predischarge electrophysiologic study could predict late outcome with recurrence of preexicitation or supraventricular tachycardia in patients who had undergone surgical ablation of the accessory pathway with an overall predictive accuracy of 95% (107 of 113 patients), negative predictive value of 96% (103 of 107), and positive predictive value of 67% (4 of 6).

Adolescent↗
PubMed1992

Medically unexplained syncope: relationship to psychiatric illness.

The purpose of this article is to review the literature and present new data concerning the relationship between psychiatric disorders and unexplained syncope. Several case series are presented of patients with syncope in whom psychiatric structured interviews were undertaken, tilt-table (physiologic) testing was performed, and health-related quality of life was measured. Patients seen in a syncope specialty clinic underwent structured psychiatric interviews in addition to in-depth medical evaluations. Tilt-table testing was performed on a separate series of patients to determine susceptibility to syncope during the orthostatic challenge of head-up tilt; in some cases, tilt studies included simultaneous electroencephalographic (EEG) monitoring and cerebral blood flow measurements. Formal functional status assessment was carried out using the Sickness Impact Profile, the Symptom Check List 90, and the Medical Outcomes Study Short-Form 36. Psychiatric disorders (in particular, panic disorders and major depression) were a common cause of syncope (24-31% of syncope patients). Tilt table studies showed several physiologic profiles in syncope: (a) a typical vasovagal (hypotension-bradycardia) response, (b) a "psychosomatic" response (fainting with normal vital signs), and (c) a gradual decline in blood pressure (dysautonomic response). EEG and cerebral blood flow measurements in three patients with the psychosomatic response to tilt were normal during fainting. Functional status measurements showed serious impairment in two series of syncope patients. Conclusions were as follows: (a) Psychiatric disorders are common in syncope. (b) Tilt-table methodology may elucidate underlying mechanisms of syncope in these subjects. (c) Syncope can seriously disrupt a patient's life and result in important psychosocial sequelae. (d) There is an intimate relationship between unexplained syncope and psychiatric illness, mandating a combined medical and psychiatric approach to such patients.

Humans↗
PubMed1992

The use of external, noninvasive pacing for the termination of ventricular tachycardia in the emergency department setting.

STUDY OBJECTIVE: To determine the potential usefulness of external cardiac pacing for the termination of sustained ventricular tachycardia in the emergency department setting. TYPE OF PARTICIPANTS: Five men and one woman (mean age, 57 years) who presented to the ED with a wide-complex, hemodynamically stable tachycardia that was later proven to be ventricular in origin. INTERVENTION: Each patient underwent external overdrive pacing using a modified external pacemaker at a pulse amplitude of 120 mA and a rate of 200 pulses per minute. RESULTS: In all six patients, external cardiac pacing was able to successfully terminate tachycardia without complication. CONCLUSION: We conclude that external noninvasive pacing may be an effective means of terminating ventricular tachycardia in the ED setting.

Adult↗
PubMed1992

Recurrent unexplained syncope in the elderly: the use of head-upright tilt table testing in evaluation and management.

OBJECTIVE: To investigate the usefulness of head-upright tilt table testing for vasovagal episodes in the evaluation and management of elderly patients with recurrent idiopathic syncope. DESIGN: Prospective survey. SETTING: Electrophysiology laboratory of a university hospital. PATIENTS: Twenty-five patients (11 male, 14 female; mean age 73 +/- 6 years) with recurrent unexplained syncope and seven control subjects with other causes of syncope (4 male, 3 female; mean age 70 +/- 4 years). METHODS: Each patient underwent head-upright tilt table testing for 30 minutes with or without an infusion of isoproterenol (1-3 micrograms/min given intravenously) in an attempt to provoke bradycardia, hypotension, or both. MAIN RESULTS: Syncope occurred in nine patients (36%) during the baseline tilt and in seven patients (28%) during isoproterenol infusion (total positives 64%). None of the controls had syncope during the test. All of the patients who had positive test results eventually became tilt table negative with therapy, and over a mean follow-up period of 24 months, no further syncopal episodes have occurred. CONCLUSIONS: Head-upright tilt table testing combined with isoproterenol infusion may be a useful tool in the diagnosis of vasovagal syncope in the elderly and in the evaluation of preventive therapy.

Aged↗
PubMed1992

Serum creatine kinase activity and sensing characteristics after intraoperative arrhythmia induction using implantable defibrillator rate sensing leads.

In 29 patients (24 men, 5 woman, mean age 57 +/- 14 years) we evaluated the effect of intraoperative arrhythmia induction during implantable defibrillator (ICD) placement using alternating current (AC) applied through the epicardial rate sensing leads on acute and chronic pacing thresholds, electrogram amplitudes, slew rates and serum creatine kinase levels. In 15 patients undergoing new ICD implantation, pacing thresholds, electrogram amplitudes, slew rates, and resistances were measured before and following at least three inductions of ventricular fibrillation (VF) using AC applied through the epicardial rate sensing leads. Fourteen patients who underwent VF induction using AC through the epicardial leads during initial implant (mean time of 31 months previously) underwent ICD pulse generator replacement only with parameters measured as above before and after at least two inductions, and these compared to the values at initial implant. In all 29 patients serum creatine kinase levels were obtained before, immediately following, and at 8, 16, and 24 hours after surgery. No significant change in acute pacing threshold, electrogram amplitude, slew rate or resistance occurred. Chronically there was an expected 154% increase in pacing threshold but no significant change in electrogram amplitude or resistance. Serial serum creatine kinase and MB isoenzyme determinations demonstrated no evidence of myocardial necrosis. We conclude that intraoperative arrhythmia induction during ICD implantation using AC applied through the rate sensing leads is a safe and effective technique.

Cardiac Pacing, Artificial↗