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Biomedical subjects

R Brockman

Publications and source records attributed to R Brockman.

11 recordsLinked to original sources

Acute hemodynamic effects of right ventricular pacing site and pacing mode in patients with congestive heart failure secondary to either ischemic or idiopathic dilated cardiomyopathy.

The hemodynamic effects of pacing in patients with congestive heart failure (CHF) remain controversial. Early studies reported that pacing from the right ventricular (RV) apex improved acute hemodynamic parameters in patients with left ventricular systolic dysfunction, but these findings were not confirmed in subsequent controlled studies. More recently, it has been proposed that pacing from the RV side of the ventricular septum improves hemodynamic function compared with intrinsic conduction or apical pacing. Either dual-chamber or ventricular pacing have been evaluated, again with inconsistent findings. To assess the effects of pacing site and mode on acute hemodynamic function, we evaluated 21 subjects with CHF and intrinsic conduction disease. Hemodynamics were compared in AAI, VVI, and DDD modes with pacing from the RV apex or high septum. The pacing rate was constant in each patient and the order of testing was randomized. In the absence of ventricular pacing (AAI mode), the mean systemic arterial pressure was 85 +/- 11 mm Hg, the right atrial pressure was 11 +/- 4 mm Hg, the pulmonary capillary wedge pressure was 18 +/- 8 mm Hg and the cardiac index was 2.4 +/- 0.7 L/min/m(2). Compared with AAI pacing, there were no improvements in any hemodynamic parameter with DDD pacing from either RV site. Hemodynamic function worsened with VVI pacing from both RV sites. Subgroup analyses of patients with dilated cardiomyopathy, with prolonged PR interval, or with significant mitral regurgitation also failed to demonstrate an improvement with pacing. We conclude that pacing mode but not RV pacing site affects acute hemodynamic function. Pacing in the DDD mode prevents the deleterious effects of VVI pacing in this patient population.

Aged↗

Inappropriate shocks from implanted cardioverter defibrillators caused by sensing of diaphragmatic myopotentials.

Inappropriate shocks remain one of the major problems associated with the use of implantable cardioverter defibrillators (ICD). We describe 3 patients who had inappropriate shocks due to oversensing of diaphragmatic myopotentials. In all 3, oversensing could be demonstrated during deep inspiration or Valsalva maneuver. The problem was remedied in one by insertion of a separate rate sensing lead in the right ventricular outflow tract, in the second by decreasing the rate of antibradycardia pacing of the ICD, and in the third by decreasing the sensitivity of the ICD. We conclude that the possibility of sensed diaphragmatic myopotentials should be considered at the time of ICD implant so that appropriate preventive measures can be taken.

Aged↗

Congenital pseudarthrosis of the tibia. Long-term followup of 29 cases treated by microvascular bone transfer.

The authors show that vascularized fibular transplantation is the safest technique to treat congenital pseudarthrosis of the tibia. Results of transplantation in 29 patients reveal that the rate and speed of healing were superior to those of any other published method, and the final outcome at maturity was generally acceptable. In addition, the technique allows secondary lengthening procedures to be done. Various factors, such as age at first fracture, age at operation, gender, and type of fixation, did not appear to influence the outcome significantly.

Adolescent↗

Surgical treatment of brachial plexus birth palsy.

Brachial plexus birth palsy remains a challenging condition. In the 1000 infants followed from 1977 to 1988, functional results were much improved over those obtained by observation only, if surgical exploration and repair were performed when no clinical recuperation of biceps function occurred by three months of age. Recovery is slow, and comprehensive follow-up study of reconstructed and conservatively managed children is required to prevent joint contractures. Children who will benefit from palliative procedures such as tendon transfers must also be identified.

Brachial Plexus↗

Medication and transference in psychoanalytically oriented psychotherapy of the borderline patient.

The regressive potential of the borderline patient has been recognized ever since the term was first introduced by Adolph Stern in 1938. He believed these patients were "too ill for classical psychoanalysis," and indeed almost all who have written on this subject have supported Stern's view, recognizing the severe regressive potential of a borderline patient in unmodified psychoanalysis. Taking medication is not generally considered to be a particularly regressive experience. It should be remembered, however, that for many patients and especially for patients with borderline personality disorder, medication can be both an overvalued hope and a terrifying assault. Thus, although the pharmacologic action of the medication may help to integrate the patient's ego functioning, the very taking of the medication may at the same time initiate subtle and unanticipated regressive drives. Two forces are then set in motion with potentially different effects. In a treatment where the same physician is prescribing medication and doing psychotherapy, the common pathway of these forces is transference. Thus, pharmacologic action may modify transference. And more importantly, because it is less easily recognized, transference issues may affect the patient's subjective experience of the action of the medication. For this reason, it is particularly important that not only diagnostic issues but also transference issues be understood before medication is prescribed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

A twelve-year survey of cervicothoracic vascular injuries.

This study of a large series of victims of trauma to the cervicothoracic great vessels confirms the lethal potential of these injuries: more than half of victims of such injuries died. The optimal management of patients potentially harboring such vascular damage appears to include skilled prehospital resuscitation and rapid transport to a trauma center, a high index of diagnostic suspicion, a low threshold for the performance of contrast arteriography, aggressive surveillance for associated neurologic and aerodigestive tract injuries, and timely technical repair, including liberal indications for sternotomy or thoracotomy to assure vascular control.

Adolescent↗

Bone disease in prolonged parenteral nutrition: osteopenia without mineralization defect.

A metabolic bone disease characterized by a mineralization defect, low plasma 1,25(OH)2D, and hypercalciuria has been described in patients receiving prolonged total parenteral nutrition (TPN). Because the practice of TPN differs from center to center, we investigated 13 home TPN patients to determine whether they had similar or different bone abnormalities. They had received TPN for a mean period of 51 +/- 38 mo. Bone pain occurred in six patients and two had multiple vertebral and rib fractures (with trauma in one patient). Bone pain was mild to moderate and not incapacitating. Bone histomorphometry showed reduced bone volume, reduced osteoid with normal resorption and calcification rates. These abnormalities were associated with hypercalciuria, but the plasma levels of 1,25(OH)2D were normal. Abnormalities in bone metabolism in this group of patients suggest a fundamental decrease in bone matrix-formation rather than a mineralization defect as the underlying mechanism.

Adult↗

Agitation, disorientation, and hallucinations in patients on cimetidine: a report of three cases and literature review.

Cimetidine, the first of a new class of pharmacologic agents that dramatically inhibit basal gastric acid secretion, is achieving widespread use for the treatment of such acid peptic disorders as duodenal ulcers, gastritis, and reflux esophagitis. Three patients are presented who experienced agitation, disorientation, and hallucinations while being treated with cimetidine. A review of the literature revealed that central nervous system side effects of cimetidine can occur within 24 hours of treatment with the drug; are often unrecognized or misdiagnosed by clinicians, and are reversed within 12 to 48 hours after the discontinuation of the medication.

Adult↗