Temazepam as premedication in elderly patients

One hundred and forty-five men were randomly allocated on a double-blind basis to receive either temazepam 20 mg, diazepam 10 mg or placebo as premedication. Temazepam produced more sedation than either diazepam or placebo. Postoperative recovery was assessed by a simple visuo-motor co-ordination test and was best in the placebo group. Two hours into recovery, temazepam patients could almost match their baseline performance whereas the performance of the diazepam patients was still significantly worse than pre-operatively. Temazepam is suggested as a suitable premedicant for elderly patients undergoing minor surgery.     

A chromogenic assay for activated protein C resistance

Summary. Resistance to activated protein C (APC) diagnosed on the basis of prolongation of clotting time in an activated partial thromboplastin time (aPTT) assay is now considered a major cause of inherited thrombophilia. The majority of patients with APC resistance carry a factor V molecule with a point mutation at one APC cleavage site (Arg506Gln) which prevents the optimal inactivation of activated factor V by APC. To overcome the limitations of aPTT-based assays in the diagnosis of APC resistance, we have developed a chromogenic assay which is based on the capacity of APC to limit the generation of factor Xa by inactivating factor Villa in plasma. The ratio of the factor Xa amidolytic activity in a sample without APC to its factor Xa activity with the addition of APC reflects the response of the plasma coagulation system to APC. The normal range in 44 healthy individuals was 1.62-2.06. APC response ratios as measured by the chromogenic assay correlated with ratios measured by the aPTT assay and were below the normal range in 23.24 individuals with Arg506Gln mutant factor V from three different families with familial thrombosis and from 11 unrelated asymptomatic individuals. In reconstitu-tion experiments, purified factor V corrected the decreased APC response in plasma samples from patients with the Arg506Gln mutation as well as with factor V deficiency, and increased the APC response in normal plasma, whereas the addition of activated factor V had no enhancing effect.     

The "Low Intensity Treadmill Exercise" Protocol for Appropriate Rate Adaptive Programming of Minute Ventilation Controlled Pacemakers

The objective of rate adaptive pacemakers that measure minute ventilation by tmnsthoracic impedance is to simulate the physiological relationship of the sensed signal to the sinus node response during exercise, thus achieving an appropriate matching of heart rate with patient effort. The purpose of this study was to determine the physiological relationship between heart rate and minute ventilation (HR/VE) during peak exercise testing in order to develop a database for appropriate rate adaptive slope programming of minute ventilation controlled pacemakers. Due to several clinical limitations of peak exercise testing, it was additionally determined whether the 35-watt “low intensity treadmill exercise” (LITE) protocol can be used as a substitute for peak exercise test using the “ramping incremental treadmill exercise” (RITE) protocol in order to assess the correct HR/VE slope below the anaerobic threshold. The stress tests were performed on a treadmill with the collection of breath-by-breath gas exchange. Linear regression analysis was used to determine the HR/VE slope below and above the anaerobic threshold and during the early, dynamic phase of low intensity exercise with the RITE and LITE protocols, respectively. The results of this testing in 41 healthy subjects demonstrated that the HR/VE relationship throughout treadmill exercise using the RITE protocol was not linear but curvilinear in nature, with a steeper HR/VE slope of 1.54 ± 0.51 below versus 1.15 ± 0.37 above the anaerobic threshold (P < 0.005). The HR/VE slope determined during the early, dynamic phase of the LITE protocol (1.58 ± 0.88) did not differ from the HR/VE slope from rest to anaerobic threshold obtained using the peak exercise RITE test (1.54 ± 0.51; P = 0.79), Rate adaptive pacing should simulate the curvilinear relationship between heart rate and minute ventilation from rest to peak exercise. The HR/VE slope determined during the early, dynamic phase of low intensity exercise represents the HR/VE slope derived from the RITE protocol below the anaerobic threshold. According to the peak exercise database, the slope above anaerobic threshold can easily be calculated as a percentage of the slope below the anaerobic threshold. The LITE protocol can, therefore, be effectively performed as a substitute for peak exercise stress tests to determine the correct pacemaker rate response factor in order to obtain a physiological heart rate to minute ventilation relationship for the appropriate matching of paced heart rate with patient effort.     

The Minimally Invasive Surgical Approach: A Critical Reappraisal

The use of minimally invasive techniques for cardiac surgery procedures has increased in the last 5 years. The term minimally invasive is used to describe cardiac procedures performed through a small incision or heart surgery performed without cardiopulmonary bypass. A review of the minimally invasive heart surgery literature is presented. According to the literature coronary bypass grafting without cardiopulmonary bypass can be carried out with similar early and mid-term results when compared to coronary bypass grafting with cardiopulmonary bypass. The same is true for LIMA to LAD bypass grafting performed through a lateral mini-thoracotomy. Controversial results are reported regarding morbidity after aortic and mitral valve surgery operated through a mini-incision. Some report less postoperative pain, earlier mobilization, shorter hospital stays, and lower costs. Others did not find any difference between full sternotomy and mini-incisions except a better cosmetic outcome. According to the literature there is no proven advantage of performing open heart surgery minimally invasively except in special situations, such as reoperation or polymorbid patients.     

Clinical Significance of Sleep-Related Breathing Disorders in Patients with Implantable Cardioverter Defibrillators

The prevalence and clinical significance of sleep-related breathing disorders (SRBDs) in patients with cardiac disease and a history of life-threatening ventricular tachyarrhythmias is unclear. Forty consecutive recipients of implantable cardioverter defibrillators (ICDs) with cardiac disease and a documented history of spontaneous, life-threatening, ventricular tachyarrhythmias underwent full night polysomnography. SRBDs were diagnosed if the apnea/hypopnea index was > 10. SRBD were diagnosed in 16 of 40 patients (40%): central sleep apnea (CSA) was present in 9 of these 16 patients (56%), 8 of whom had associated Cheyne-Stoke respiration. Seven of the 16 patients with SRBD (44%) had obstructive sleep apnea (OSA). Patients with and without SRBDs were comparable with respect to left ventricular ejection fraction, NYHA classification, underlying heart disease, ICD indications, and concomitant antiarrhythmic drug and beta-blocker therapy. Patients were followed prospectively for 2 years. ICD-treated ventricular tachyarrhythmias occurred in 10 of 24 patients (42%) without SRBD, in 4 of 9 patients (44%) with CSA, and in 3 of 7 patients (44%) with OSA (NS). The numbers and circadian distributions of episodes recorded during follow-up in patients without SRBD versus with CSA or OSA were not significantly different (14 ± 25, median = 4 vs 4 ± 5, median = 2.5 vs 15 ± 15, median = 7, respectively). The 2-year mortality, which was entirely attributable to nonsudden cardiac events, was highest in patients with CSA (4/9 [44%], vs 0/7 [0%] with OSA, vs 3/24 patients (12.5%) without SRBD; P < 0.05).     

A Novel Mutation in the Gene Encoding Noggin is Not Causative in Human Neural Tube Defects

Neural tube defects (NTD) are a common birth defect, with both genetic and environmental contributions to their etiology. In mouse, null mutations in Noggin result in fully-penetrant NTDs. We investigated Noggin for mutations that may predispose to human NTDs in 202 NTD cases. One variant allele was identified in a male patient with myelomeningocele. The patient's father and a sibling also carried the variant allele, but neither was affected with an open NTD. DNA sequencing confirmed a C1064A missense mutation predicted to result in the conversion of residue 84 from proline to histidine. The variant found in the NTD patient is a newly identified variant, the role of which is uncertain.     

Atrial Fibrillation Therapy in Patients with a CRT Defibrillator with Wireless Telemetry

Background: Atrial fibrillation (AF) is a major cause of morbidity and mortality, especially in patients with congestive heart failure.
Objectives: The purposes of this international, prospective multicenter study were to evaluate the efficacy of atrial shock therapy in patients with a cardiac resynchronization therapy defibrillator (CRT-D) and to evaluate the safety of the new CRT-D. The effectiveness of a new wireless telemetry system was also evaluated.
Methods: A total of 282 patients, without permanent AF, who had indications for a CRT-D were included. Atrial shock therapy was tested on both spontaneous and induced AF episodes. The effectiveness of the Medtronic wireless telemetry system (Conexus; Medtronic Inc., Minneapolis, MN, USA) was also tested. Secondary endpoints included the heart failure Clinical Composite Response, system performance evaluation, and adverse event summary.
Results: Atrial shock therapy was successful in 168 of 171 episodes (98.2%). Of these, 138 episodes were induced and 33 were spontaneous. Successful cardioversion occurred in 137 of the 138 induced-AF episodes (86.1% with 12 joule (J), 13.1% with 24 J, and 0.7% with 35 J). During the first 3 months of implant, there were 43 system-related complications in 37 subjects out of 278 subjects. There were 1,999 Conexus telemetry uses recorded during this study. This includes 282 uses during the implant procedure. There were no cases of complete loss of telemetry or any adverse events reported using this system.
Conclusion: We achieved an atrial shock efficacy of 98.2% in patients who met standard CRT-D indications. The wireless telemetry performed well with no reported unanticipated adverse device effects.