Verapamil or Adenosine for the Immediate Treatment of Supraventricular Tachycardia

A comparison of verapamil with adenosine for the immediate treatmentof supraventricular tachycardia was made from a retrospectivereview of 164 spontaneous episodes of paroxysmal tachycardiain 43 patients. Verapamil administered to 33 patients restoredsinus rhythm in 91 of 112 episodes (81 per cent). Hypotensionoccurred in 9 per cent of episodes. Adenosine terminated 94per cent of episodes of supraventricular tachycardia in 25 patients.The arrhythmia recurred shortly after adenosine restored sinusrhythm in 20 episodes. Transient side effects were common. Fifteenpatients were treated with both agents. Adenosine was successfulin all, but verapamil failed to restore sinus rhythm at leastonce in seven of the 15 patients. Early recurrence of tachycardiaoccurred in five of these after adenosine, but in only one afterverapamil. Verapamil and adenosine are both effective in the treatmentof supraventricular tachycardia; adenosine has the higher successrate and is safer, but transient symptoms are common and arrhythmiasmay recur.     

Clinical Experience with an Activity Sensing Pacemaker

During clinical evaluation of the Medtronic * Activitrax pacemaker in a worldwide multicenter study, implant and follow-up data were provided by 61 investigators on 222 patients. Pacing indications included two- and three-degree AV block in 149 and atrial arrhythmias in 174 patients; 16 patients received atrial pacing. Average and longest documented follow-up periods were 7.5 and 16 months respectively. Paired treadmill tests, one in Activity mode and one in VVI/AAI mode, were performed by 120 patients. At peak exercise, average heart rate was 95 bpm in VVI/AAI mode and 118 bpm in Activity mode (p < 0.0001). Average exercise time was 9.4 minutes in VVI/AAI mode and 10.8 minutes in Activity mode (p < 0.0001). In 54 patients who exclusively had paced rhythm during both treadmill tests, average heart rates and exercise times were 70 ppm and 8.1 minutes in VVI/AAI mode and 111 ppm and 10.3 minutes in Activity mode respectively (p < 0.0001). 24-hour Holter recordings typically demonstrated pacing at or near basic rate during periods of rest and appropriate increase in pacing rate during daily activities. Patients had significantly fewer problems with physical effort in daily life during a week of Activity mode pacing than during a week of VVI/AAI mode pacing (p < 0.05) as assessed from the symptom scores recorded by 62 patients in special diaries.     

Definition of novel GP6 polymorphisms and major difference in haplotype frequencies between populations by a combination of in-depth exon resequencing and genotyping with tag single nucleotide polymorphisms

BACKGROUND: Common genetic variants of cell surface receptors contribute to differences in functional responses and disease susceptibility. We have previously shown that single nucleotide polymorphisms (SNPs) in platelet glycoprotein VI (GP6) determine the extent of response to agonist. In addition, SNPs in the GP6 gene have been proposed as risk factors for coronary artery disease. METHODS: To completely characterize genetic variation in the GP6 gene we generated a high-resolution SNP map by sequencing the promoter, exons and consensus splice sequences in 94 non-related Caucasoids. In addition, we sequenced DNA encoding the ligand-binding domains of GP6 from non-human primates to determine the level of evolutionary conservation. RESULTS: Eighteen SNPs were identified, six of which encoded amino acid substitutions in the mature form of the protein. The single non-synonymous SNP identified in the exons encoding the ligand-binding domains, encoding for a 103Leu > Val substitution, resulted in reduced ligand binding. Two common protein isoforms were confirmed in Caucasoid with frequencies of 0.82 and 0.15. Variation at the GP6 locus was characterized further by determining SNP frequency in over 2000 individuals from different ethnic backgrounds. CONCLUSIONS: The SNPs were polymorphic in all populations studied although significant differences in allele frequencies were observed. Twelve additional GP6 protein isoforms were identified from the genotyping results and, despite extensive variation in GP6, the sequence of the ligand-binding domains is conserved. Sequences from non-human primates confirmed this observation. These data provide valuable information for the optimal selection of genetic variants for use in future association studies.     

EPIDEMIOLOGY OF ALCOHOLIC CIRRHOSIS

Seventy-seven alcoholic patients, 54 men and 23 women, had cirrhosis of the liver when they first attended the Alcoholism Clinic at St Vincent's Hospital, Melbourne, between July, 1964, and June, 1968. During this period 800 chronic alcoholics, 663 men and 137 women, attended the clinic. Cirrhosis was thus diagnosed twice as often in women as in men. The case histories of the 77 cirrhotic patients were reviewed, and information was collected about socio-economic status and drinking habits. This information was compared with that obtained from a sample of 220 patients--all those who attended the Alcoholism Clinic between July, 1966, and June, 1967. Most of the cirrhotic patients were beer drinkers, as are the majority of Australian alcoholics. Relatively more cirrhotics were habitual excessive drinkers. The cirrhotic patients did not drink more heavily, but they had drunk excessively for longer when their cirrhosis was diagnosed. Cirrhotic women, however, had drunk excessively for a significantly shorter time than cirrhotic men. No difference was found in the incidence of either social isolation or clinical peripheral neuropathy between cirrhotic and alcoholic patients, or between male and female cirrhotics. Cirrhosis was not commoner among the lower socio-economic groups. These findings were interpreted as suggesting that nutrition did not play an important part in the causation of the liver disease. Women appear to be more susceptible than men to cirrhosis of the alcoholic, and unremitting habitual excess more damaging than intermittent alcohol abuse. Some undetermined predisposition must also exist, since the disease is still sporadic even when these factors operate.