A Prospective, Randomized Evaluation of a Nonthoracotomy Implantable Cardioverter Defibrillator Lead System

Nonthoracotomy lead systems for ICDs have been developed that obviate the need for a thoracotomy and reduce the morbidity and mortality associated with implantation. However, an adequate DFT cannot be achieved in some patients using transvenous electrodes alone. Thus, a new subcutaneous "array" electrode was designed and tested in a prospective, randomized trial that compared the DFT obtained using monophasic shock waveforms with a single transvenous lead alone that has two defibrillating electrodes, the transvenous lead linked to a subcutaneous/submuscular patch electrode, and the transvenous lead linked to the investigational array electrode. There were 267 patients randomized to one of the three nonthoracotomy ICD lead systems. All had DFTs that met the implantation criterion of ≤ 25 J. The resultant study population was 82% male and 18% female, mean age of 63 ± 11 years. The indication for ICD implantation was monomorphic VT in 70%, VF in 19%, monomorphic VT/VF in 6%, and polymorphic VT in 4% of the patients, respectively. The mean LVEF was 0.33 ± 0.13. The mean DFT obtained with the transvenous lead alone was 17.5 ± 4.9 J as compared to 16.9 ± 5.5 J with the lead linked to a patch electrode (P = NS), and 14.9 ± 5.6 with the lead linked to the array electrode (array versus lead alone, P = 0.0001; array versus lead/patch, P = 0.007). The results of this investigation suggest that the subcutaneous array may be superior to the standard patch as a subcutaneous electrode to lower the DFT and increase the margin of safety for successful nonthoracotomy defibrillation.     

SUPRANORMAL FSH RESPONSE TO GONADOTROPHIN-RELEASING HORMONE IN OLIGOSPERMIC MEN WITH A NORMAL BASAL SERUM FSH CONCENTRATION

Twenty-six men with severe oligospermia (sperm density less than 10 X 10(6)/ml, but greater than O), but normal serum concentration of FSH, as well as normal serum concentrations of LH and testosterone, were given a 250 microgram i.v. bolus dose of synthetic gonadotrophin releasing hormone (LHRH). The serum FSH and LH responses were compared to those of a group of normal men and a group of men with oligospermia or azoospermia and elevated basal serum FSH concentration. The mean FSH response to LHRH of the men with oligospermia but normal basal serum FSH concentration was 911 miu min/ml, nearly three times that of the normal men, 322 miu min/ml (P less than 0.001), though not so great as that of the men with oligo/azoospermia and elevated basal FSH concentration (2890 miu min/ml). Ten of the twenty-six men with oligospermia and normal basal serum FSH had a supranormal FSH response to LHRH. The mean LH response to LHRH of the men with oligospermia and normal basal serum FSH levels was not significantly different from that of the normal men. We conclude that LHRH stimulation can often elicit a deficiency of feedback inhibition of FSH secretion not readily recognizable by measurement of the basal serum FSH concentration.     

Congenital Erythropoietic Protoporphyria: II. An Experimental Study

Investigations into the pathophysiology of erythropoietic protoporphyriasuggest that the basic defect is an inborn error of metabolism resulting inthe overproduction of protoporphyrin IX by the bone marrow not in responseto a failure of heme synthesis. A method is described for evaluating the invitro synthesis of protoporphyrin and heme by human bone marrow.

Submitted on January 10, 1963 Accepted on July 3, 1963     

Advanced training in general practice in the UK for overseas postgraduates

The strengths of general practice in the UK as a training environment for overseas doctors intending to implement the World Health Organization strategy 'Health for All by the Year 2000' in primary care are identified. A course of advanced training for teachers and administrators of primary care is described and evaluated in terms of participants' academic achievements and wider issues, including influence upon the development of primary care in their countries of origin.