Long-term survival of VDD pacing.

UNLABELLED: All patients with VDD systems implanted at a tertiary pacing center were identified from a computer database and data collected on pacing indications, follow-up duration, rate response, reasons for programming changes, and implant P wave amplitudes. RESULTS: 366 implants were identified for which complete data were available for 335 leads implanted in 316 patients. The mean follow-up period was 24.1 months, and age at implant was 73.5 +/- 11.8 years. During follow-up, 19 patients died (6%) and 62 (19.6%) were followed elsewhere. Indications for pacing were complete heart block, 56.6%; intermittent AV block, 21.8%; postablation complete heart block, 5.4%; 2:1 AV block, 13%; and others, 3.2%. Two groups: no mode change (NMC, n = 280) and mode change (MC, n = 36) were identified. Reasons for reprogramming in the MC group were as follows: atrial sensing, 11; AF/atrial flutter, 18; chronotropic incompetence, 3; and others 4. Significantly more MC patients had rate response programmed ON (44.4% vs 22.1%, P < 0.05). No significant differences between the two groups were found in other variables, including male gender (55.5% vs 54.6%), length of follow-up (27.1 +/- 17.8 vs 23.8 +/- 20.6 months), age at last follow-up (72 +/- 12.3 vs 75.9 +/- 11.9 years), and P wave amplitude (1.7 +/- 0.9 vs 1.8 +/- 0.9 mV). CONCLUSION: Reprogramming of VDD systems is infrequent. When necessary, it is usually prompted by atrial arrhythmias or failure of atrial sensing. When adequate atrial chronotropy has been verified, VDD is an acceptable alternative to DDD pacing and survives well over the long term.

Salter-Harris type III epiphyseal fractures of the proximal phalanx.

Of 823 pediatric hand fractures treated between 1981 through 1996, only 11 (1.3%) were Salter-Harris type III fractures of the proximal phalanx. We review the anatomic basis, etiology, age prevalence, treatment, and results of these epiphyseal injuries. The average age at injury was 14.9 years, with a narrow range from 14 years 2 months to 15 years 11 months. Nine of 11 fractures were displaced and treated with open reduction and internal fixation. At an average follow-up of 21 months, 9 of 11 had full joint motion. The other two had minimal loss of motion, and all had normal function and collateral ligament stability. The displacement and size of the epiphyseal fragment, avulsed and rotated by the collateral ligament, are often underestimated by radiographs. We found that anatomic reduction and fixation yielded good results in all displaced fractures. This restores both the stability of the collateral ligament and a smooth articular surface.

Evolution of atrial signals from a single lead VDD pacemaker. AddVent European Multicentre Study Group.

The atrial sensing capabilities of a new single pass lead VDD pacing system (Pacesetter AddVent) were assessed in a prospective multicenter study of 101 implants during the period July 1994 through March 1996. The pacing lead (Pacesetter AV Plus) has a unique quadripolar 4-in-line connector and uses a pair of ring electrodes with an interelectrode spacing of 12 mm for atrial sensing. The mean age of the patients (51 men) was 73 years (range 19-91). Seventy-five patients had complete heart block; the others had 2:1 AV block. Wide variations were found in signal amplitude: mean P wave amplitude, measured over four cycles in the supine position, was 2.4 +/- 1.9 mV at implant, dropping to 1.9 +/- 1.7 mV predischarge, and remaining constant at follow-up but with a narrower range. Holter monitoring was undertaken in 24 patients, with a total of 550 monitored hours. Mean AV synchrony was 98.2% +/- 4.6% (excluding premature ventricular contractions), with 20 patients (83%) showing > 99% AV synchrony, with atrial sensing at 0.1 mV where needed. No oversensing was observed in any patient. There was a low incidence of atrial fibrillation (2%) and sinus bradycardia (0%). The findings show that the range of atrial signals, although wide initially, converges over the first year and remains adequate for reliable AV synchronous pacing.

Successful long-term ventricular pacing via the coronary sinus after the Fontan operation.

A man with double inlet left ventricle and severe subpulmonary stenosis underwent a Fontan operation at the age of 29 years. Eight years later he developed atrial flutter with complete heart block. To avoid a further thoracotomy, a unipolar carbon tipped electrode was placed into the posterior cardiac vein via the coronary sinus. More than 8 years after implantation of the original lead, and after two generator changes, telemetric thresholds remain between 1.8-2.1 volts. Percutaneous transvenous ventricular pacing via the coronary sinus can produce an excellent long-term result and should be the initial approach of choice after a Fontan-type operation.

Long term follow-up study of a single lead VDD pacing system

At he previous Wordl Symposium (1991) a study of 1002 patients undergoing implantation of the Phymos VDD pacing system (MEDICO - Italy), provided with an atrial dipole of 3 cm, in 60 European centres was presented. Follow-up of these patients has been continued to assess the reliability of the system and to investigate the natural history of the conduction disorder over a mean period of 5 year. Of 924 patients with data vailable, after a mean follow-up of 50.3 months, 795 of 904 (87.9 por cento) we still paced satisfactorily in VDD mode. Problems caused by arrhytmias were few: atrial fibrillation 5 por cento, sinus bradycardia 1 por cento. The findings demonstrated that the VDD mode remaisn approprieate in the great majority of patients with atrioventricular block and that the Phymos system provides reliable physiological pacing in the long term.

The effects of succimer on the absorption of lead in adults determined by using the stable isotope 204Pb.

The chelating agent succimer (meso-2,3-dimercaptosuccinic acid) is orally effective at inducing a urinary lead diuresis and a decrease in blood lead levels in lead poisoned children and adults. However, there are concerns that succimer may increase the absorption of lead from the gastrointestinal (GI) tract during treatment, particularly in cases of continuing lead exposure, which would compromise its effectiveness in reducing whole body lead stores. This preliminary study investigated the effects of succimer on the absorption of lead in adults using a stable lead isotopic tracer (204Pb). Twelve male subjects were divided into control (no succimer), 10, and 30 mg succimer/kg body wt treatment groups of 4 individuals each. All subjects ingested a single tracer dose (200 micrograms) of 204Pb, followed by a single oral dose of placebo (control) or succimer. Whole blood was collected at intervals of 0, 2, 4, and approximately 26 hr following ingestion of the 204Pb tracer, and composite urine and feces samples were collected over the duration of the study (approximately 26 hr). Mean intestinal excretion of 204Pb was reduced in the succimer-treated groups compared to the control (placebo), whereas urinary diuresis of 204Pb was higher in the succimer groups. The amount of lead 204Pb tracer accounted for at the end of the study was lower in the succimer-treated groups. These results suggest that GI lead absorption was enhanced by succimer and that succimer mediated the redistribution of lead from the circulation to other tissues. However, none of the differences between treatment groups were statistically significant (P < 0.05, t test) because of the relatively large within-group variability. This study demonstrates the utility of microgram doses of a stable lead isotopic tracer to assess the efficacy of clinical chelating agents in humans. Future studies are necessary to further clarify the effects of succimer on the absorption and retention of lead in adults and children. Although, based upon these preliminary data, it appears advisable that patients be maintained in a lead-safe environment while being treated with succimer.

Hemostatic studies in patients with infective endocarditis: a report on nine consecutive cases with evidence of coagulopathy.

Local and generalized changes in coagulation may be important in the genesis of vegetations and embolism in infective endocarditis. To characterize such alterations, serial hematological investigations were performed on nine consecutive patients who satisfied the inclusion criteria. Platelet survival was measured by Indium111 labeling. Acute and convalescent samples were analyzed for fibrinogen, factor VIIIc, antithrombin III (AT III), fibrin/fibrinogen degradation products (FDPs), and platelet aggregation. The results suggest that in the active stage of the disease: (1) hypercoagulability may be caused by a rise in acute phase reactants, (2) an acceleration of coagulation and fibrinolysis may supervene, and (3) in some cases there is a reduction in platelet aggregation, possibly as a result of continued circulation of previously activated "exhausted" platelets.

Irreducible palmar dislocation of the proximal interphalangeal joint with bilateral avulsion fractures.

An unusual case of an irreducible anterior fracture dislocation of the proximal interphalangeal joint in a child with open epiphyses is described. Bilateral intraarticular avulsion fractures at the proximal attachment of the collateral ligaments were present, and the phalangeal head was locked through a tear in the central slip.

Osteochondrosis of the fourth metacarpal head after closed trauma.

A rare case of osteochondrosis of the fourth metacarpal head after blunt trauma to the hand is presented. Follow-up at 2 years showed mild residual deformity both clinically and radiographically, but the child was asymptomatic. The cause of this condition is unknown, but it appears to be one of the few osteochondroses related to a single episode of direct trauma.

Use of monoclonal antibody against human neutrophil elastase in normal and leukaemic myeloid cells.

A monoclonal antibody, NP57, was produced and used against the neutrophil granule protein elastase, which selectively stain neutrophils in cryostat and paraffin wax sections. The antibody stains neutrophils and a subpopulation of monocytes in blood smears and neutrophil precursors in bone marrow smears, and gives positive reactions with the cell lines HL60 and U-937. It labelled the blast cells in 68% of cases of acute myeloid leukaemia (M1-M5) but was unreactive with all cases of lymphoid leukaemias. Most of the elastase negative myeloid leukaemias were labelled by monoclonal anti-myeloperoxidase (antibody MPO-7) as were cells from the promyelocytic line HL60. No cases of myeloid leukaemia showed the opposite pattern--that is elastase positive, myeloperoxidase negative, suggesting that the production of myeloperoxidase precedes the onset of elastase synthesis during myeloid maturation. The anti-elastase antibody NP57 is a useful addition to the range of monoclonal antibodies available for the differential diagnosis of acute leukaemia by alkaline phosphatase-antialkaline phosphatase (APAAP) labelling of cell smears; it may also be of value for the histopathological diagnosis of tumour deposits in myeloid leukaemia and for the detection of neutrophils in paraffin sections.

Pediatric hand injuries. Types and general treatment considerations.

Growth arrests may occur after fractures, burns, and frostbite injuries, but children generally have a better prognosis from most hand and forearm injuries than adults. Stiffness is less frequent, open wounds heal faster, remodeling of angular deformities may occur, and nerve recovery following repair is significantly better than adults. Parents should be aware of potential problems and the need for follow-up care for evaluating growth and scar development. Perhaps the greatest challenge for nurses as both parents and as members of society is the prevention of traumatic hand injuries. Children should be placed in seat belts when riding in motor vehicles, and toys and play areas should be geared toward the child's developmental age and abilities. Despite careful attention to a child's surroundings, some children will require emergency care for traumatic hand injuries. Health care workers must provide emotional support for parents who may feel guilty about their child's injury. They also must be prepared to give skilled clinical care guided by the child's development and the needs of the family members.

Fascicular nerve repairs. A comparative study of epineurial and fascicular (perineurial) techniques.

At present, fascicular nerve repairs produce almost identical results to epineurial repairs. There are still theoretical advantages to the improved alignment potentially offered by fascicular nerve repair, and fascicular technique already offers an advantage in partial nerve injuries. As fascicular capabilities improve, fascicular nerve repair may still offer the best solution for nerve recovery.

Open reduction and internal fixation of volar lip fractures of the distal radius.

Fractures of the volar lip of the distal radius are relatively uncommon injuries. However, controversy exists concerning the treatment of these fractures. We reviewed our experience with open reduction and internal fixation through a volar approach using buttress plates. Sixteen patients with 17 fractures were treated by this method. Their ages ranged from 16 to 65 years (average 38 years). Eight fractures occurred secondary to motor vehicle accidents, while the remaining patients sustained falls. Mean follow-up time was 19.5 months. All fractures healed with no infections. Sixteen of the fractures were treated primarily with open reduction and internal fixation, while one patient was treated 6 weeks after injury for a malunion. Ranges of motion averaged 71 degrees dorsiflexion, 60 degrees palmar flexion, 79 degrees pronation, 78 degrees supination, 22 degrees radial deviation, and 32 degrees ulnar deviation. Analysis of results demonstrated 12 excellent, 2 good, and 3 fair results. Two patients with fair results had nonanatomic restoration of the joint surface at surgery, while the other patient with a fair result was treated late. We recommend early open reduction and internal fixation of displaced or unstable volar lip fractures of the distal radius. Accurate anatomic alignment and stable fixation are achieved with the volar buttress plate. Motion can begin 2-3 days after surgery to aid in obtaining excellent functional results.

The effects of early coronary patency on the evolution of myocardial infarction: a prospective arteriographic study.

The effects of early spontaneous coronary patency on the evolution of myocardial infarction were evaluated in 41 patients. They had coronary arteriography (mean (SEM)) 3.1 (0.2) hours after the onset of chest pain with repeat studies 90 minutes and three days later. In 12 (29%) patients the infarct related coronary artery was patent at the first arteriogram (group 1). A further 10 patients, nine of whom received thrombolytic treatment, showed early recanalisation of the infarct related coronary artery within 90 minutes of treatment (group 2). In the remainder the infarct related coronary artery was persistently occluded (group 3). Baseline values for infarct location, the sum of ST elevation in all leads, QRS scores, and serum creatine kinase activity did not permit discrimination between the groups. Nevertheless, patterns of ST segment change and enzyme release in group 1 were closely similar to those that occurred in response to thrombolysis in group 2. Thus compared with group 3, groups 1 and 2 showed earlier 50% reduction in the sum of peak ST elevation in all leads and earlier peaking of serum creatine kinase activity. Importantly, creatine kinase release was significantly attenuated in group 1, rising to a peak serum activity (mean (SEM)) of only 1242 (415) IU/1. Analysis of angiographic left ventricular ejection fractions at three days indicated limitation of infarct size in groups 1 and 2 compared with group 3. Mean (SEM) ejection fraction, however, was best preserved in group 1 (62(6)%) and in this group the frequency of non-Q wave infarction was higher than in groups 2 and 3. Thus in patients who present with a patent infarct related coronary artery early during infarction: (a) there is a reduction in the pattern of infarct size as reflected by attenuation of release of creatine kinase, preservation of left ventricular ejection fraction, and a relatively high frequency of non-Q wave infarction; (b) patterns of ST segment change and creatine kinase release resemble those that occur after successful thrombolytic treatment, suggesting that early coronary patency is the result of spontaneous recanalisation of a previously occluded artery.