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Biomedical subjects

A Fitzpatrick

Publications and source records attributed to A Fitzpatrick.

33 records · Page 2Linked to original sources
PubMed1991

The incidence of malignant vasovagal syndrome in patients with recurrent syncope.

We reviewed 322 patients with recurrent syncope between 1984 and 1988. Investigation included limited intracardiac electrophysiological study in all cases with programmed extra-stimulus studies in 48 cases. In 93 patients (29%), all investigations were normal, (including negative extrastimulus in 30). In the other 229 cases syncope was explained by AV-block (n = 111, 34%), sinus node disease (n = 68, 21%), carotid sinus syndrome (n = 32, 10%) and inducible sustained tachyarrhythmia (n = 18, 6%). Prolonged 60 degrees head-up tilt was performed in 71 out of 93 patients with unexplained syncope, and reproduced vasovagal syncope and presenting symptoms in 53 (75%), or 16% of the whole population reported. These patients were diagnosed as having malignant vasovagal syndrome. Positive tilts were significantly less common in a group of 27 subjects of similar age without a history of syncope (7%), and a random sample of 37 patients with atrioventricular block (n = 16), sick sinus syndrome (n = 18) and inducible tachyarrhythmia (n = 3), (19%, 11% and 0% respectively, P less than 0.01). From this retrospective review it appears, therefore, that tilt testing is a valuable provocative tool for vasovagal syncope and may reduce the number of syncopal patients that remain undiagnosed, although these early observations do not allow an exact appraisal of the sensitivity and specificity of the tilt test.

Arrhythmias, Cardiac↗
PubMed1991

Dual chamber pacing aborts vasovagal syncope induced by head-up 60 degrees tilt.

To determine if pacing might prevent syncope in cardioinhibitory 'Malignant Vasovagal Syndrome' (also known as 'Neurally-Mediated Bradycardia/Hypotension'), a study of dual chamber pacing during head-up 60 degrees tilt was undertaken. Paired invasive tilts were performed in 10 patients who had a history of recurrent syncope, normal routine investigations including electrophysiological study and prior tilt-induced vasovagal syncope. Vasovagal reactions of identical severity were produced by prolonged 60 degrees head-up tilt on consecutive days in seven out of 10 patients. On day 2, without pacing, seven patients had tilt-induced vasovagal reactions and six became syncopal during the reaction. On day 3, with temporary DVI pacing with rate hysteresis, seven patients had tilt-induced vasovagal reactions and 1 patient was syncopal. Syncope was aborted in the other five patients. DVI pacing significantly improved cardiac index (CI) (one +/- 0.2 to 1.6 +/- 0.3 L/min/m2, P less than 0.01) and mean arterial blood pressure (MABP) (30 +/- 11 to 48 +/- 12 mmHg, P less than 0.01) during vasovagal reactions on day 3 compared with day 2. The mean period of time that patients could tolerate in the tilted position after the onset of the tilt-induced vasovagal reaction was significantly prolonged by pacing from 0.9 +/- 1.2 to 3.2 +/- 1.6 min (P less than 0.01). Dual chamber pacing may abort syncope in 85% of patients with cardioinhibitory malignant vasovagal syndrome. Pacing may prolong consciousness sufficiently during a vasovagal reaction to allow injury to be avoided.

Adult↗
PubMed1991

Natural history of sinus node chronotropy in paced patients.

The natural history of chronotropic incompetence is not clear. To assess this, we evaluated corrected sinus node recovery time (cSNRT) and sinus node chronotropy at rest and during exercise in two groups of syncopal patients with sinus node disease. Group A comprised patients with resting bradycardia but normal cSNRT and group B had resting bradycardia and prolonged cSNRT (greater than 1000 ms). An additional two groups (C and D) were studied. Group C comprised patients with complete AV (CAVB) and no evidence of sinus node disease and group D were asymptomatic controls of similar age. At diagnosis, patients with symptomatic bradycardia but normal cSNRT and no evidence of carotid sinus syndrome (group A) had resting bradycardia and impaired peak heart rate (PHR-I) on exercise compared to controls (P less than 0.001 and P less than 0.05, respectively), but no reduction in exercise duration. At follow-up group A patients demonstrated an increase in resting rate that was significantly slower than the controls (P less than 0.01). Peak heart rate (PHR-II) also remained significantly slower (P less than 0.05). There was no difference in exercise duration between groups A and D at follow-up. Group B was further subdivided according to follow-up findings of preservation of atrial activity in seven patients (group B-1) and junctional rhythm without any atrial activity in four patients (group B-2). Retrospective analysis showed no significant difference in resting heart rate at initial examination but group B-2 showed a significantly lower peak heart rate on exercise compared with B-1 (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

How and when to investigate syncope.

Recurrent syncope is a distressing phenomenon and may be very difficult to treat where the cause remains obscure. A methodical approach to investigation will often be fruitful when proper emphasis is given to thorough clinical assessment and simple investigations. Where these are normal, head-up tilt testing will often diagnose 'malignant vasovagal syndrome'.

Electrocardiography↗
PubMed1989

Tilting towards a diagnosis in recurrent unexplained syncope.

71 patients with recurrent syncope which remained unexplained after standard clinical and electrophysiological investigation underwent 60 degree head-up tilt. This procedure reproduced symptoms with vasovagal syncope in 53 (74%), 40 of whom had bradycardia, some with prolonged asystole, during syncope. The other 13 patients had predominant vasodepression with hypotension. Mean time to syncope after tilt was 25 min. Patients with conduction tissue disease and age-matched control subjects had a 15% and 7% incidence of tilt syncope, respectively. Temporary dual-chamber pacing aborted syncope in 85% of subjects, and improved cardiac index and systemic blood pressure during tilt. Long-term results indicate that selected patients may benefit from permanent dual-chamber pacing. Head-up tilt is useful in the investigation of unexplained syncope because symptoms are reproduced in front of a medical witness.

Aged↗
PubMed1987

Catholic institutions: mirror or model for society?

Certain values and priorities help establish and shape an organization's identity. Catholic organizations--through the values by which they operate--can determine whether they function as a centrifugal force that shapes the values of the larger society or whether they are driven by the centripetal force of American values, thus accommodating their actions to succeed in self-serving, narrow ways. Catholic organizations can evaluate their practices against three "environments," each composed of value strata, that characterize workplaces: Subpersonal environment. Workers are alienated; the employee is seldom acknowledged as a person. Stratum one--base values. The operative values focus on mechanical working qualities such as punctuality and productivity, rather than human interaction. Stratum two--civil values. Some interaction takes place, but it is geared only to customer satisfaction. Relational environment. Relationships are important to organizational functioning. Stratum three--corporate values. Workers must have more interpersonal skills but are seen as a means to an end: benefit for the corporation. Stratum four--ethical culture values. The worker is recognized as a person to be respected. Operative values are fair play and improving the human condition. Religious environment. Workers affirm the existence of a Godhead, which creates a "community" workplace. Stratum five--Judeo-Christian values. A commitment to charity and mercy and serving others is evident. Stratum six--Catholic values. Persons are seen as the body of Christ; the organization challenges society's tenets when these ignore the human person.(ABSTRACT TRUNCATED AT 250 WORDS)

Catholicism↗
PubMed1980

Pharmacokinetics of vinblastine-loaded platelets utilized in the treatment of platelet-phagocytizing tumors.

Vinblastine-loaded platelets (VLP) have been successfully used in the treatment of idiopathic thrombocytopenic purpura. Three patients with platelet-phagocytizing tumors and thrombocytopenia were treated with VLP. Patient 1 has sustained a response for 11 months. Patient 2 was not evaluable for response because of early death. Patient 3 had a brief partial response. Vinblastine levels were measured by radioimmunoassay in the platelet-rich plasma, platelet-poor plasma, and serum. The pharmacokinetic data obtained on the patients suggest that: (a) the amount of vinblastine bound to platelets in vivo is a function of the platelet-poor plasma vinblastine level and the platelet count; (b) VLP will probably not have any therapeutic advantage, compared with iv vinblastine alone in patients with normal platelet counts; and (c) it appears that delivery of vinblastine was tumor-specific, since the bone marrow serum vinblastine level in patient 2, obtained when the marrow was replaced by tumor cells, was 2.5-fold higher than a simultaneous peripheral blood serum vinblastine level after VLP. Additional studies with VLP appear warranted in patients with platelet-phagocytizing tumors resulting in thrombocytopenia.

Adult↗
PubMedDate not supplied

Systemic chemotherapy for a primary germ cell tumor of the brain: a pharmacokinetic study.

Systemic administration of most chemotherapeutic agents has been assumed to be ineffective in the treatment of primary and metastatic brain tumors because these agents fail to cross the intact blood-brain barrier. However, agents which fail to penetrate the intact blood-brain barrier may penetrate it under conditions which include the presence of tumor in the central nervous system (CNS) and prior CNS irradiation. This paper reports the results of pharmacokinetic studies of bleomycin, cisplatin, and vinblastine in the CNS of a patient with a primary germ cell tumor of the brain who had received prior radiotherapy. Significant concentrations of bleomycin and cisplatin, but not of vinblastine, were reached in the cerebrospinal fluid (CSF) of the patient following iv administration. The area under the bleomycin CSF concentration times time curve was 25% of the area under the bleomycin plasma concentration times time curve. The areas under two cisplatin CSF curves were 50% and 155% of the areas under the corresponding free cisplatin plasma curves. Moreover, an objective response of the tumor to the chemotherapy was documented. This study provides evidence that, under certain circumstances, significant concentrations of cisplatin and bleomycin may be obtained in human CSF following systemic administration and that it may be possible to treat primary or metastatic CNS tumors with agents effective against systemic tumor of the same histologic type.

Antineoplastic Agents↗
PubMedDate not supplied

Phase I trial of chlorozotocin: attempted amelioration of myelotoxicity by glucose administration.

Chlorozotocin is a new anticancer agent with the chloroethylnitrosourea cytotoxic moiety attached to the carbon-2 position of glucose. Like other chloroethylnitrosoureas, this agent produces delayed myelotoxicity which is dose-limiting. A phase I trial of chlorozotocin with administration of glucose was done in an attempt to modify the myelotoxicity. The patients received the first course of chlorozotocin (200 mg/m2) in the fasting state and then the second course of chlorozotocin with boluses of a 50% glucose solution. With the second course of chlorozotocin administration, the glucose concentration remained threefold greater than after the first course for at least 1 hour. The plasma half-life and apparent volume of distribution of chlorozotocin were similar following either course. The wbc, neutrophil, and platelet count nadirs after the first course of this agent were not significantly different than the nadirs after the second course. We were unable to modify the myelotoxicity of chlorozotocin with boluses of a 50% glucose solution.

Blood Glucose↗