Survival of Patients with the Automatic Implantable Cardioverter Defibrillator

Between May 1982 and May 1988, 37 patients (28 males and 9 females, mean age 57.6, range 16–76 years) of approximately 600 evaluated for sustained ventricular tachycardia and/or fibrillation (VT/VF) were treated with an automatic implantable cardioverter defibrillator (AICD). Twenty-eight of the patients had coronary artery disease, 7 had nonischemic cardiomyopathy, 1 had amyloid hear disease, and 1 had rheumatic heart disease. The mean ejection fraction was 32.2 ± 12.9% (range, 9–64%). Eleven patients have died at a mean of 16.7 months after implantation. The cumulative survival rate was 81% at 1 year, 77% at 2 years. 68% at 3 years, and 53% at 4, 5, and 6 years. Considering only sudden deaths, the survival was 97% at 1 and 2 years, 90% at 3 years, and 80% at 4, 5, and 6 years. Twenty-one of the 37 patients received spontaneous shocks. If the first shock marks the time to death in the absence of an AICD, the cumulative survival rate would have been 56% at 1 year, 42% at 2 years, 29% at 3 years, and 14% at 4, 5, and 6 years. The maximum amount of time to a first appropriate shock was 39.7 months. Thirty-nine devices have been explanted; 28 for battery depletion; 5 for infections; 3 for improper sensing; 2 for electronic failure; and 1 at the time of cardiac transplantation. The average time to failure of the 28 units removed for battery depletion was 19.8 ±6.9 months. We conclude that in this group of patients, short-term survival is increased by AICD implantation, hut long-term survival remains poor. Incidence of sudden death is reduced to 3% at 1 and 2 years, 10% at 3 years, and 20% after 4 years. Other patient selection criteria may be useful in selecting those patients whose survival will be improved by the AICD.     

EFFECT OF NALOXONE ON GASTRIC EMPTYING DURING LABOUR

The rate of gastric emptying was studied in 30 women duringlabour. All the women had received pethidine 100 mg i.m. foranalgesia and, subsequently, extradural analgesia had been establishedfor obstetric indications. The women were allocated randomlyto two groups: 15 received naloxone 1.2 mg i.v. and 15 weregiven saline 3 ml (placebo). All 30 patients were then givenparacetamol 1.5 g orally with water 100 ml. The amount of paracetamolabsorbed, and hence gastric emptying, was significantly greaterin the naloxone group in the first 30 min following the administrationof the paracetamol. ^*Present Addresses: Department of Anaesthesia, Southern GeneralHospital, 1345, Govan Road, Glasgow G51 4TF. Present addresses: Department of Anaesthesia, Ninewells Hospital,Dundee.     

The Atrial Electrogram During Clinical Electrophysiologic Studies: Onset versus the Local/Intrinsic Deflection

The Local Atrial Deflection. Introduction : As a wave front passes unfiltered bipolar recording electrodes, the point of local depolarization is marked by a maximal change in voltage, i.e., the intrinsic deflection. However, during electrophysiologic studies, the depolarization (A) on the lead recording the His-bundle potential traditionally has been measured at the first rapid reproducible deflection on a filtered electrogram. This methodology permits considerable latitude for subjective interpretation. The purpose of this study was to assess the timing of the atrial electrogram using the intrinsic deflection of relatively unfiltered electrograms (0.1-4.0 to 1,250 Hz) or the equivalent on filtered recordings. Methods and Results : To do this we studied 70 patients without evidence of atrial or atrioventricular (AV) nodal disease, documenting the difference in timing between the A wave as traditionally measured and as measured at its peak local deflection (A_L) determined from simultaneously recorded filtered and relatively unfiltered electrograms. New ranges based on the A_L were established for timing of intra-atrial and AV nodal conduction intervals. The P-A (41 ± 11 msec) was significantly shorter than the P-A_L (55 ± 12) and the A-H (80 ± 20) was longer than the A_L-H (66 ± 21 msec), both P <0.001. Interobserver differences in measurements were smaller when using the local (A_L) rather than traditional criteria. Conclusions : Conventional measurement of the A deflection provides only a rough estimate of local depolarization of the atrium near the AV node. The criteria proposed in the present article may (1) provide a better estimate of the timing of local depolarization; (2) have application in computerized timing of intervals; and (3) decrease technical problems and subjective error.     

Thrombocytic acroangiothrombosis (platelet thrombosis of the capillaries,arterioles, and venules)

It is believed that there is a definite disease syndrome characterized clinically byfever, marked anemia, purpura, thrombocytopenia, central nervous system involvement, and a progressive fatal course of a few weeks’ duration. Histologically thepresence of platelet thrombi in the capillaries, arterioles, and venules is pathognomonic. Only by histologic demonstration of the platelet thrombi can the diseasebe definitely differentiated from idiopathic thrombocytopenic purpura.

The data of 9 previously reported cases of this rare disease are summarized and2 additional cases reported.

Diagnosis of the disease probably can be made by bone marrow biopsy or, possibly, by skin biopsy. If a case be diagnosed and the patient is not responding toconservative treatment it is suggested that splenectomy be considered.

Spleens removed for thrombopenic diseases should be examined for plateletthrombi in the possibility that unrecognized cases of the disease have been treatedby this procedure. Proper evaluation of splenectomy in this disease might be aidedby follow-up study of any cases showing platelet thrombi.

The name "thrombocytic acroangiothrombosis" is suggested for this disease.

     

Initial Experience with Transvenous Implantable Cardioverter Defibrillator Lead Systems: Operative Morbidity and Mortality

Introduction of non-thoracotomy lead systems™ (Medtronic, Inc.) for the implantable cardioverter defibrillator (ICD) has expanded the indications for use of this mode of therapy. Patients previously considered "too ill" to undergo a thoracotomy as well as patients who are at a high risk for developing sudden death but without previous cardiac arrest, are now considered candidates. The initial experience with the non-thoracotomy lead system at our institution was analyzed for morbidity and mortality. Thirty-four patients underwent attempted intravascular lead implantation, with 30 having initial successful implantation (88.2%). There were 23 males; average ejection fraction (EF) was 38.6%. Three patients developed pulmonary edema and low output immediately after the procedure. Three patients developed electromechanical dissociation during defibrillation threshold testing. A prolonged testing time for the non-thoracotomy lead system was noted when compared to the thoracotomy system (57.39 vs 32.30 min; P < 0.0000). There were more intraoperative morbidities with the non-thoracotomy leads than with the thoracotomy system. There were no perioperative deaths. The potential consequences of prolonged anesthesia time and extensive defibrillation threshold testing should be considered when choosing the route of ICD implant, the type of anesthesia, and the intraoperative testing protocol for each patient.     

EXTRADURAL ANAESTHESIA FOR CAESAREAN SECTION IN ACHONDROPLASIA

We describe the successful management of a 26-yr-old achondroplasticdwarf undergoing elective Caesarean section under extraduralanaesthesia. The patient had marked thoraco-lumbar kyphoscoliosisand clinical features which suggested that tracheal intubationwould prove difficult. Block sufficient for surgery requiredonly 5 ml of 0.5% bupivacaine and, apart from an initial unilateralblock and mild intraoperative hypotension, her perioperativecourse was uneventful. ^* Present address: Department of Anaesthesia, Green Lane Hospital,Green Lane, Auckland, New Zealand.     

Inhalation Toxicity of an Isomeric Mixture of Hydrochlorofluorocarbon (HCFC) 225 in Male Rats

A blend of the hydrochiorofluorocarbon isomers HCFC-225ca andHCFC-225cb has been proposed as a potential substitute for CFC-113,an important solvent and cleaning agent. The toxicity followingrepeated inhalation of an HCFC-225 isomer mixture was assessedin male Crl:CDBR rats. Three groups of 10 male rats were exposedto the test compound in air at design concentrations of 500,5000,and 13,000 ppm. Rats were exposed 6 hr/day, 5 days/week for2 weeks. A control group of 10 male rats was exposed to aironly. Decreased serum cholesterol, triglycerides, and glucose;dose-related increased mean absolute and relative liver weights;and microscopic hepatocellular hy pertrophy were present atall exposure concentrations. Hepatocellular hypertrophy correlatedultrastructurally to proliferation of peroxisomes. Clinicalchemical parameters and organ weight and morphologic changesin the liver were reversible following 14 days of recovery.     

Maternal height and shoe size as predictors of pelvic disproportion: an assessment

Summary. A total of 351 women who gave birth in the Paddington and North Kensington Health District were studied in order to establish a factual basis for recording height and shoe size as indicators of pelvic adequacy. Because only 19 women had radiological pelvimetry assessment, type of delivery and length of labour were used as proxy measures of disproportion. Of the 57 women with a shoe size <4½, 21% were delivered by caesarean section compared with 10% of the group with shoe size between 4½ and 6 and only 1% of the group with shoe size 6½. Similar relations with height were not generally found. The data were further examined using logistic regression models of the expected percentages of mothers having an adverse delivery. The models confirmed and extended the more simple analysis.     

PROFESSOR ROBERT WALMSLEY (1906–1998)

Robert Walmsley, Emeritus Professor of Anatomy at the University of St Andrews, died on 24 August 1998 aged 92. He was appointed Bute Professor of Anatomy in St Andrews University in 1946, after a distinguished career in the University of Edinburgh, where he was appointed demonstrator in Anatomy with J. C. Brash as professor and E. B. Jamieson as senior lecturer. He carried out studies on the vertebral column and the knee joint with John Bruce (later Sir John Bruce), Professor of Surgery in Edinburgh, with whom he was associated in the production of 3 editions of a textbook of surgical anatomy. His work on the vascular system of the whale, conducted at the Carnegie Institute of Embryology in Baltimore, USA, was the subject of his thesis for the MD (Edinburgh University) which was awarded with honours and gold medal in 1937.