Self-selection of enrollers at the creation of a managed care organization

Factors affecting choice between a managed care organization(MCO) and a fee-for-service insurance plan were examined whenthe University of Geneva health insurance plan was transformedinto an MCO, in October 1992. A case-control study using a mailedquestionnaire (response rate 84%) was conducted to compare formermembers who joined the MCO (joiners, n=421) to former memberswho opted out in order to keep fee-for-service coverage (non-joiners,n=222). Non-joiners were more likely to be women (odds ratio(OR) from multivariate model was 1.15, p=0.50), to be born inSwitzerland (OR=2.04, p<0.01), to have an annual income >75,000Swiss francs (OR=2.00, p<0.01), to have a personal physician(OR=1.96, p<0.01) and to have consulted a specialist (OR=1.69,p=0.02) or used unconventional medicine (OR=4.59, p<0.01)in the past year. During the previous year, non-joiners hadmore health care visits than joiners (14.6 versus 9.1, p=0.01).Non-joiners reported better mental health and fewer complainedof persistent fatigue (OR=2.18, p=0.03). The choice of healthplan was strongly influenced by socio-demographic characteristics,past patterns of health services utilization and health status.The self-selection process was paradoxical: MCO joiners hadused fewer health care visits than non-joiners, but their self-reportedhealth status was worse. The differences we have observed betweenself-selected populations have important implications for thefinancial performance of competing health care delivery systems.     

Long-term Prevention of Vagal Atrial Arrhythmias by Atrial Pacing at 90/Minute: Experience with 6 Cases

Six patients (5 men, 1 woman) with a history ranging from 3–16 years of resistant vagal atrial arrhythmias were treated by atrial pacing at a rate of 90Jmin. These patients have been followed up for an average of 5.5 years (range 2–11 years) with favorable resutls. The arrhythmias were charactemed by daily or weekly attacks of rypical alrial flutter and atrial fibrillalion occurring mainly or exclusively at night, at rest, or in the digestive periods in otherwise normal hearts of middle-aged palients (first attack between 25 and 54, mean 40). The arrhythmias werc resistant to quinidinc, and were usually aggravated by digitalis, beta-blockers and verapamil. Amiodaroneisusually the only effective drug in this syndrome, but was not used before pacing in the 2 first cases, and was in effective in the other 4 cases. Electrophysiologic studies confirmed the absence of sick sinus syndrome, and the close relationship betwecn a relative bradycardia and the onset of the arrhythmia. Atrial pacing alone totally controiled the arrhythmia in 1 palient; amiodarone was used in conjunction with pacing in 3 palients. In 1 patient the improvement was clear but incomplete, and in 1 patient permanent alrial fibrillation occurred shortly afler pacemaker implantalion.     

POSTOPERATIVE ANALGESIA WITH EXTRADURAL CLONIDINE

The analgesic effect of extradural clonidine was evaluated ina double-blind study. In the recovery room, following orthopaedicor perineal surgery 20 ASA I and II patients were allocatedrandomly to two groups. The extradural clonidine (EC) groupreceived clonidine 2 µg kg^–1 in isotonic salinesolution 15 µg ml^–1. The extradural saline (ES)group received the equivalent volume of plain isotonic salinesolution. Pain was evaluated by a visual analogue scale (VAS)at 15-min intervals for the first 2 h and subsequently at 30-minintervals for the following 4 h. Morphine 5 mg was given s.c.when patients complained of pain after extradural saline orclonidine. In the EC group, the mean (SD) maximum pain reliefwas 68.2 (24.1)% of the initial VAS score, but it was only 14.7(25.2)% in the ES group. The mean duration of analgesia, beforeinjection of morphine, was significantly longer in the EC group(210 (87) min) compared with the ES group (45 (27) min) (P <0.001). Drowsiness and moderate hypotension were observed inthe EC group.     

Meta-Analysis of Positive Blood Cultures During Transesophageal Echocardiography

We have reviewed ten prospective studies of bacteremia with transesophageal echocardiography (TEE) in 720 patients. The incidence of TEE related positive culture is low, and general recommendation for antibiotic prophylaxis during TEE is not warranted.     

Small-Diameter Implants: Indications and Contraindications

The choice of implant diameter depends on the type of edentulousness, the volume of the residual bone, the amount of space available for the prosthetic reconstruction, the emergence profile, and the type of occlusion. Small-diameter implants are indicated in specific clinical situations, for example, where there is reduced interradicular bone or a thin alveolar crest, and for the replacement of teeth with small cervical diameter. Before using a small-diameter implant, the biomechanical risk factors must be carefully analyzed. Preliminary reports of this type of implant show good short- and medium-term results.
CLINICAL SIGNIFICANCE
Specific clinical situations indicate the use of small-diameter implants: a reduced amount of bone (thin alveolar crest) and where the replacement tooth requires a small cervical diameter. In some cases, the use of small-diameter implants avoids bone reconstruction.     

Radiofrequency Ablation Guided by Mechanical Termination of Idiopathic Ventricular Arrhythmias Originating in the Right Ventricular Outflow Tract

Mapping of Idiopathic Ventricular Arrhythmias. Background: Termination of ventricular tachycardia (VT) by mechanical pressure has been described for fascicular and postinfarction VT. Mechanical interruption of idiopathic ventricular arrhythmias (VT/premature ventricular complexes [PVCs]) arising in the right ventricular outflow tract (RVOT) has not been described in systematic fashion. Methods: Eighteen consecutive patients (13 females, age 49 ± 13 years, ejection fraction 0.55 ± 0.12) underwent mapping and ablation of RVOT VT or PVCs. In 7 patients, 9 distinct VTs (mean cycle length 440 ± 127 ms), and in 11 patients, 11 distinct PVCs originating in the RVOT were targeted. Mechanical termination was considered present if a reproducibly inducible VT was no longer inducible or if frequent PVCs suddenly ceased with the mapping catheter at a particular location. Endocardial activation time, electrogram characteristics, and pace‐mapping morphology were assessed at this location. Radiofrequency energy was delivered if mechanical termination was observed. Results: All targeted arrhythmias were successfully ablated. In 7 of 18 patients (39%), catheter manipulation terminated the arrhythmia with the mapping catheter located at a particular site. Local endocardial activation time was earlier at sites of mechanical termination (?31 ± 7 ms) compared with effective sites without termination (?25 ± 3 ms, P = 0.04). The 10‐ms isochronal area was smaller in patients with mechanical interruption (0.35 ± 0.2 cm²) than in patients without mechanical termination (1.33 ± 0.9 cm², P = 0.01). At all sites susceptible to mechanical trauma, the pace map displayed a match with the targeted VT/PVC. All sites where mechanical termination of VT or PVCs occurred were effective ablation sites. Conclusions: Mechanical suppression at the site of origin of idiopathic RVOT arrhythmias frequently occurs during the mapping procedure and is a reliable indicator of effective ablation sites. Mechanical termination of RVOT arrhythmias may be indicative of a more localized arrhythmogenic substrate. (J Cardiovasc Electrophysiol, Vol. 21, pp. 42–46, January 2010)     

Catheter Ablation of Left Parietal Accessory Pathways

Fifty-one patients with a left parietal pathway and drug refractory tachycardia underwent transcatheler ablation of their accessory pathway. Three had single concealed pathways, two had multiple pathways, and the remaining 46 had the Wolff-Parkinson-While syndrome. Two patients were resuscitated from a cardiac arrest related to a ventricular fibrillation. A multipolar (quadri-, hexa-, or octopolar) electrode catheter was positioned within the coronary sinus in order to localize the pathway accurately. An ablation catheter was then introduced either through a patent foramen ovale (11 patients), by transseptal catheterization (14 patients) or a retrograde arterial catheterization (26 patients). The mitral annulus was mapped with this catheter during orthodromic tachycardia in order to record ventriculoatrial (VA) time as short as (or even shorter than) that recorded in the coronary sinus. The VA time in our series was 82 ± 13 msec. Two 160-joule cathodal shocks were delivered at this site and eventually repeated according to the results (73 sessions/51 patients). The mean cumulative energy was 650 ± 205 joules. No significant side effects occurred except one case of a right coronary artery spasm leading to inferior wall infarction. During follow-up of 2–49 months, all but two patients were free of tachycardia. Twelve patients were reassessed 4 to 8 months after the procedure: conduction over the pathway was absent, and no vascular damage was noticed. Catheter ablation of left parietal accessory pathways is both effective and safe. Ablation by retrograde arterial catheterization was as efficient as the tranxseptal approach. This method is an attractive alternative to surgery.     

EFFECTS OF VARIOUS CYTOCHROME P-450 INDUCERS ON TESTOSTERONE METABOLISM AND SEVERAL MONOOXYGENASE ACTIVITIES IN SPRAGUEDAWLEY (SpD), HIGH ALCOHOL SENSITIVITY (HAS) AND LOW ALCOHOL SENSITIVITY (LAS) RATS

Hydroxylation of testosterone (TST) has been shown to be regio-and stereo-specific for a number of cytochrome P-450 isoenzymes.Three rat lines [Sprague-Dawley (SpD), high alcohol sensitivity(HAS) and low alcohol sensitivity (LAS)] were tested for thisenzymatic specificity after treatment with phenobarbital, clofibrate,3-methylcholanthrene and pregnenolone-16-carbonitrile. Thesecompounds are known to induce cytochrome P-450 2B, 4A, 1A and3A1. respectively, in the rat. Induction efficiency was establishedby using the usual enzyme activities specific for these P-450s(pentoxyresorufin, lauric acid, ethoxyresorufin and nifedipineoxidase). Five mono hydroxylated TST metabolites were separatedusing a sensitive HPLC procedure. The hydroxylation of TST wasfound to be significantly different between the lines even inthe uninduced state. The formation of the metabolites of TST,hydroxylated on 2 or 7 or 16 positions and oxidated on carbon17 (4), was found to be significantly increased in SpD ratswhen compared with the HAS-LAS lines (P < 0.0001 in eachcase). When the HAS-LAS lines were compared, the quantity of2 and 16 hydroxylated metabolites was found to be significantlylower in LAS rats (P < 0.05). These differences persisted,although in the opposite direction, after 3-methylcholanthrene(P < 0.01 for both 2 and 16) and phenobarbital induction(P < 0.01 for 2). In conclusion, large differences in TSThydroxylation were found between the SpD and HAS-LAS rats whilemore subtle differences were found between the more closelyrelated HAS-LAS lines especially after phenobarbital and 3-methylcholanthreneadministration as confirmed by our enzyme activity results.The above differences in steroid metabolism between HAS andLAS rats may help to explain their contrasting sensitivitiesto alcohol.