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Biomedical subjects

R E Espinosa

Publications and source records attributed to R E Espinosa.

16 recordsLinked to original sources
PubMed2001

Breath-holding spells associated with significant bradycardia: successful treatment with permanent pacemaker implantation.

OBJECTIVE: To determine whether children with pallid breath-holding spells associated with bradycardia can be treated safely and successfully with permanent pacemaker implantation. METHODS: The records of pediatric patients who had apparent breath-holding spells and associated bradycardia and were treated with permanent pacemaker implantation were reviewed. RESULTS: Ten pediatric patients with apparent breath-holding spells associated with bradycardia were treated with a permanent ventricular demand pacemaker at the Mayo Clinic between 1985 and 1995. Patients had onset of symptoms between ages 6 days and 12 months and presented for evaluation between ages 12 months and 5 years. Duration of spells was 15 seconds to 10 minutes. Medications to prevent spells were unsuccessful. Electrocardiograms documented asystolic pauses of 1.7 to 24 seconds (mean: 11.9 seconds). Permanent ventricular demand pacemakers were implanted at 10 months to 5 years of age (median: 14.5 months): 9 endocardial and 1 epicardial. Three patients required pacemaker revision. At follow-up of 38 to 170 months (median: 65.5), 5 patients had complete resolution of spells, 2 had only mild color change without loss of consciousness or seizure activity, and 3 continued to have minor brief spells. CONCLUSIONS: Permanent pacemaker therapy for children with pallid breath-holding spells associated with severe bradycardia is safe, efficacious, and warranted.

Apnea↗
PubMed1996

Extraction of the Telectronics Accufix 330-801 atrial lead: the Mayo Clinic experience.

OBJECTIVE: To document a cumulative experience with removal of the Telectronics 330-801 Accufix atrial lead after it was withdrawn from the market. DESIGN: We reviewed our results with 96 attempted lead extraction procedures through Dec. 1, 1995. MATERIAL AND METHODS: All patients underwent preoperative assessment, including fluoroscopic screening of the lead. Patients had blood typing and screening done before the extraction procedure, and extractions were performed with cardiac surgical intervention available. Pacing dependence was assessed to determine the need for temporary pacing. RESULTS: The mean patient age was 65.7 +/- 1.6 years and the mean duration of lead implantation was 31.0 +/- 1.4 months. Of the 96 lead extractions attempted, 94 were successful. Of the 96 cases, the retention wires were normal in 29, fractured without protrusion in 34, and fractured with protrusion in 33. Fifty-three leads were removed with use of simple traction only, and seven leads were removed by using a locking stylet and telescoping sheaths. The Cook workstation was used in the removal of 32 leads through the femoral vein; in 1 of these 32 patients, the retention wire was removed before lead extraction. The retention wire was removed but the lead was left intact in one patient. One lead was removed during an opertive maze procedure. Associated complications were minimal. CONCLUSION: Although lead extraction is a potentially fatal procedure, the Telectronics 330-801 Accufix atrial lead can be extracted safely with minimal morbidity when performed by experienced personnel.

Aged↗
PubMed1995

Expanding indications for permanent pacemakers.

PURPOSE: To review the current clinical experience with new and expanding indications for permanent cardiac pacing. DATA SOURCES: A MEDLINE search was done of the English-language literature published from 1980 through 1994 about indications for permanent pacing. Five major areas were identified and searched: cardiomyopathies, atrial fibrillation, the long QT syndrome, cardiac transplantation, and vasovagal syncope. A manual search was then done for other contributions, including abstracts. STUDY SELECTION: Because published reports in these areas are scarce, all of the peer-reviewed articles and most of the relevant abstracts found were reviewed. DATA EXTRACTION: Data were manually extracted from the various sources, and the reports were classified and summarized according to specific indications. RESULTS: Pacing is becoming an important option in the treatment of patients with symptomatic drug-resistant hypertrophic obstructive cardiomyopathy. Symptomatic and hemodynamic benefits have been shown in patients with pacing over various periods of follow-up. In patients with the long QT syndrome in whom medical therapy had failed, pacing at relatively fast rates markedly reduced symptoms and almost completely abolished fainting spells. Preliminary results suggest that pacing may be beneficial in dilated cardiomyopathy and in preventing episodes of paroxysmal atrial fibrillation. Further studies are needed to clarify the mechanisms of and to improve selection criteria for pacing in these conditions. Our ability to select cardiac transplant recipients for permanent pacing and our ability to optimize the timing of pacing in these patients have recently improved considerably. The role of pacing therapy in patients with neurally mediated (vasovagal) syncope remains incompletely understood. Better classification of these patients, made according to the sequence of hemodynamic events leading to syncope, is likely to clarify the potential benefit of pacing in these patients and improve the selection of patients for pacing. CONCLUSION: Few peer-reviewed clinical trials have been done, and further studies are needed to confirm the promising effects of pacing in patients with these newly recognized and expanding indications for pacing.

Atrial Fibrillation↗
PubMed1994

Consistent subcutaneous prepectoral implantation of a new implantable cardioverter defibrillator.

OBJECTIVE: To describe the use of a new implantable cardioverter defibrillator (ICD) that can be placed in the prepectoral region rather than implanted in the abdominal wall. DESIGN: We report the experience of placement of this new ICD in the prepectoral region in 13 patients from Sept. 28, 1993, through Jan. 10, 1994, at the Mayo Clinic. MATERIAL AND METHODS: Thirteen consecutive patients offered this new ICD underwent placement of transvenous defibrillation leads, and the pulse generator was placed in a pocket formed in the subcutaneous, prepectoral space. Testing ensured a defibrillation threshold of 24 J or less. RESULTS: In all 13 patients, the pulse generator could be placed in the subcutaneous, prepectoral space. In all except one patient, acceptable defibrillation thresholds were achieved by using lead systems placed totally transvenously. Only one patient required placement of a subcutaneous patch. All but two patients were dismissed from the hospital within 3 days after the ICD implantation. CONCLUSION: Consistent subcutaneous, prepectoral placement of this new ICD pulse generator is possible. Because the entire procedure can be performed in the pacemaker implantation room, the potential exists for decreasing the duration of the hospitalization and associated costs.

Aged↗
PubMed1993

Idiopathic pulmonary hilar fibrosis: an unusual cause of pulmonary hypertension.

A 37-year-old man with progressive exertional dyspnea had pulmonary hypertension associated with pulmonary arterial and venous obstruction. An autopsy revealed that the cause of death was idiopathic pulmonary hilar fibrosis, a variant of mediastinal fibrosis. Pulmonary hilar fibrosis can mimic thromboembolic pulmonary hypertension, pulmonary veno-occlusive disease, and pulmonary venous hypertension.

Adult↗
PubMed1993

The Dotter retriever and pigtail catheter: efficacy in extraction of chronic transvenous pacemaker leads.

Several techniques exist for percutaneous extraction of chronic pacemaker leads. To establish the efficacy of the Dotter retriever and pigtail catheter, we reviewed the removal of 59 endocardial pacemaker leads in 42 patients (mean age 71 years). The mean duration of lead implantation was 44 months (range 1-169 months). Thirty-two leads were withdrawn with simple traction alone, and five leads were abandoned when traction failed. The remaining 22 leads were manipulated with a Dotter retriever or pigtail catheter, or both. Twelve leads were dislodged from the endocardium with simple traction (10) or with traction transmitted through an entwining pigtail catheter (2), but they could not be fully withdrawn. Eleven of these leads (92%) were then successfully extracted with the Dotter retriever. Seven of the remaining 10 leads were successfully dislodged and removed by the Dotter retriever. Overall, 9 of 12 leads (75%) that could not be dislodged from the endocardium with simple traction were removed with a Dotter retriever or pigtail catheter, or both. Three patients in whom no catheter method worked required thoracotomy for removal of infected leads. No complications resulted from use of the Dotter retriever or pigtail catheter. We conclude that the Dotter retriever and pigtail catheter have moderate efficacy for dislodging chronic endocardial leads. Once mobilized, however, the leads can be withdrawn with great success with the Dotter retriever. Newer technology should not result in the abandonment of this proven technique.

Adolescent↗
PubMed1984

Effect of thyroxine administration on phosphate transport across renal cortical brush border membrane.

Previous studies indicate that in hyperthyroid states the renal tubular reabsorption of phosphate is enhanced. To determine the cellular basis of this phenomenon, we investigated the effect of L-thyroxine (T4) administration on Pi transport across brush border membrane vesicles (BBMV) from rat renal cortex. Rats were thyroparathyroidectomized, fed a diet containing 1.2% phosphate, and treated intraperitoneally for 6 days with 200 micrograms T4 X 100 g body wt-1 X day-1. At the end of the treatment period, the rats had a significantly (+ delta 25%) elevated plasma Pi and a slightly decreased plasma Ca compared with controls. The renal clearance of Pi was not different between the two groups. Na+ gradient-dependent uptake of 32Pi by BBMV from renal cortex was significantly enhanced in T4-treated rats. BBMV uptake of 32Pi in the absence of Na+ -gradient as well as Na+ gradient-dependent uptake of D-[3H]glucose and L-[3H]proline did not differ between BBMV from T4-treated and control rats. Kinetic analysis showed that the Na+ gradient-dependent 32Pi transport system in BBMV from T4-treated rats had a significantly increased Vmax compared with controls (5.2 +/- 0.4 vs. 4.1 +/- 0.4 nmol Pi X 30 s-1 X mg protein-1) and also a slightly higher affinity for Pi (apparent Km in controls, 95 +/- 9; in T4-treated, 78 +/- 8 microM). Gluconeogenesis in cortical slices was not significantly different between T4-treated rats and controls. Specific activities of alkaline phosphatase and gamma-glutamyltransferase were significantly lower in BBMV from the T4-treated group compared with controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1978

Contribution of the electroencephalogram in monitoring cardiac dysrhythmias.

It is often difficult to distinguish between episodic cerebral symptoms resulting from primary disorders of the brain and those resulting from cardiac dysrhythmias. When patients with such symptoms are referred for electroencephalography, the electrocardiographic activity recorded concurrently can provide additional useful diagnostic information. Two cases are presented to illustrate the contribution of the electroencephalogram in the diagnosis of significant cardiac dysrhythmias.

Aged↗
PubMed1975

Frequency of nerve fiber degeneration of peripheral motor and sensory neurons in amyotrophic lateral sclerosis. Morphometry of deep and superficial peroneal nerves.

Among 10 patients with amyotrophic lateral sclerosis who had combined biopsy of muscle and cutaneous nerves, two had a history of paresthesia that suggested involvement of peripheral afferent neurons. Of four patients without paresthesia, two had unequivocal abnormalities of touch-pressure sensation of the toe. On morphometric evaluations of lateral fascicles of deep peroneal nerve, one nerve had an abnormally low myelinated fiber density and seven of 10 had abnormally high frequencies of teased-fiber abnormalities. Teased fibers in which myelin was degenerating into linear rows of myelin ovoids and balls occurred in 10.5 percent of fibers in amyotrophic lateral sclerosis nerves as compared with 1.7 percent in control nerves (0.01 less than p less than 0.025). Estimates of density of myelinated fibers were less sensitive than estimates of the frequency of various changes in teased fibers for detecting abnormality.

Aged↗