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Biomedical subjects

D Hunt

Publications and source records attributed to D Hunt.

At least 145 records · Page 8Linked to original sources
PubMed1983

Comparison of lead complications with polyurethane tined, silicone rubber tined, and wedge tip leads: clinical experience with 822 ventricular endocardial lads.

Lead-related complications have been prospectively studied for 602 unipolar tined endocardial ventricular pacemaker leads implanted over a five-year period. No differences were noted in overall complication rates between 238 polyurethane insulated leads (4.2%) and 364 silicone rubber insulated leads (3.6%). Comparing the total series of 602 tined leads to a retrospective survey of 220 wedge tip leads, a marked reduction in dislodgements (0.3% vs. 7.7%, P less than 0.001) and reoperations (2.0% vs 15.0%, P less than 0.001) was found using tined leads. We conclude that tined ventricular leads are far superior to wedge tip leads with respect to lead complications.

Arrhythmias, Cardiac↗
PubMed1982

Prediction of sudden death by electrophysiologic studies in high risk patients surviving acute myocardial infarction.

Seventy patients surviving a myocardial infarction complicated by heart failure or arrhythmias, or both, were studied 7 to 20 days after the infarction. Twenty-four hour electrocardiographic ambulatory monitoring and intracardiac electrophysiologic studies were performed in each patient. Electrophysiologic studies included introduction of single right ventricular premature stimuli during sinus rhythm (70 patients), atrial pacing (35 patients) and ventricular pacing (70 patients) at a stimulating voltage of 2 V, with the use of higher stimulating voltages (up to 10 V), and double right ventricular premature stimuli in 33 patients and pacing at a second right ventricular site in 50 patients. A repetitive response was defined as two or more spontaneous ventricular depolarizations in response to the premature stimuli, with His bundle reentry and aberrant conduction of supraventricular impulses excluded by a His bundle recording. Repetitive responses were initiated in 20 patients, and 12 patients had responses that were either sustained ventricular tachycardia or self-terminating ventricular tachycardia of more than five complexes in duration. The finding of a repetitive response was not related to the occurrence of complex ventricular arrhythmias during ambulatory monitoring or in the coronary care unit. Five of the 12 patients with sustained or self-terminating responses of more than five complexes died during the 12 month follow-up period, 4 suddenly, and these responses were significantly associated with late sudden death (p less than 0.05), because only 1 of 25 patients with responses of fewer than five complexes or no response to maximal provocation died suddenly. It is concluded that induced responses of more than five complexes in duration may be an important indicator of a potentially reversible risk of sudden death after myocardial infarction.

Adult↗
PubMed1982

Subendocardial myocardial infarction.

Sixty-one consecutive patients with acute subendocardial myocardial infarction (SEAMI) and 223 consecutive patients with transmural infarction (TMI) seen in a coronary care unit were followed for one year. All patients were less than 70 years of age. The patients with SEAMI had a higher frequency of previous infarction (34% vs 21%, p less than 0.025), less cardiac failure (44% vs 65%, p less than 0.005), and were more often free from arrhythmias (61% vs 31%, p less than 0.001) than patients with TMI. Hospital mortality was less in patients with SEAMI (0% vs 8%, p less than 0.05) but total mortality to one year was similar (15% vs 17%). Amongst patients with SEAMI, two died within two weeks of infarction but all other deaths occurred at least six weeks after infarction. Patients with SEAMI and a history of previous infarction had a higher one year mortality than patients without such a history (29% vs 7%, p less than 0.05). Coronary angiography with a view to coronary artery surgery should be considered in the former group.

Aged↗
PubMed1982

Spontaneous EEG correlates of intellectual functioning in talented and handicapped adolescents.

EEG correlates of intellectual functioning were investigated in 35 academically talented and 20 academically handicapped adolescents. EEG data from Ertl's Brainwave Analyzer were factor-analyzed and factor scores entered into regression equations predicting four primary mental abilities, verbal, numerical, reasoning, spatial, and two sequential tests of educational progress, reading and mathematics. Analysis indicated that (1) frequency ratio, with relatively greater left-hemisphere activity was the most important EEG variable related to mental functioning in the talented group; (2) while EEG period and alpha ratio were the two most important EEG variables related to intellectual functioning in the mentally handicapped group; (3) hemispheric symmetry was of some importance for both groups, with greater symmetry being associated with superior performance. Contrary to Ertl's neural efficiency theory, (1) neural information transfer rate was significantly positively (not negatively as predicted) related to intellectual performance (for the handicapped group only), and (2) alpha was significantly related to intellectual functioning (for the handicapped group only). Further research is needed to extend and confirm the above findings dealing with persons scoring in the normal IQ range and during mentally active as well as resting conditions.

Adolescent↗
PubMed1982

Erythrocytapheresis (red cell exchange).

Automated erythrocytapheresis (red cell exchange) was performed on two patients with sickle cell disease using the IBM 2997 Blood Cell Separator. Preoperative red cell exchange was performed on patient L.N. to prevent possible anterior ischemic syndrome during surgery. A red cell exchange procedure on patient A.Y. diminished her acute sickle crisis symptoms and resolved respiratory complications. For each patient, the instrument settings were varied in order to achieve the desired effect for the hematological needs of the individual patient.

Acute Disease↗
PubMed1981

The value of postcardiac infarction exercise stress testing: identification of a group at high risk.

We prospectively selected 154 patients who had survived acute myocardial infarction with electrical and/or mechanical complications to undergo an exercise stress test, four to six weeks after discharge from the Coronary Care Unit, Royal Melbourne Hospital. The patients exercised on a bicycle ergometer until they were unable to continue or had reached 70% of their predicted maximum heart rate for their age. Eighteen (11.7%) patients exhibited flat ST-depression of 1 mm or more on exercise. Six of these 18 patients later died (33.3%). Only seven (5.1%) of the 136 patients who exhibited no electrocardiographic change died during follow-up. We conclude that patients recording positive exercise stress test results after acute myocardial infarction, have a poorer prognosis and therefore should be considered for more intensive medical or surgical treatment.

Arrhythmias, Cardiac↗
PubMed1981

The St Jude medical valve - the Australian experience.

Since October, 1978, 181 St Jude medical cardiac valves have been implanted in 166 patients throughout Australia. There were 152 single implants, 13 combined mitral and aortic valve implants, and one triple valve implant. Hospital mortality rates were similar to those for all types of prosthetic cardiac valves. Thromboembolic complications occurred less frequently in the patients with St Jude valves than in reports of similar patients with other prostheses, provided that anticoagulation was maintained.

Adolescent↗
PubMed1981

Results of coronary artery surgery.

Four hundred and two patients undergoing coronary artery surgery from 1972 to 1978 inclusive have been followed up; 343 patients had coronary artery surgery without associated surgical procedures. In the over-all experience, the operative mortality rate was 5% falling to 1.5% in recent years. The seven-year survival rate was 90% compared with a 92% for an age-sex matched population. Late survival figures have improved with further surgical experience and the 30-month survival is now 98%. Seven per cent of patients sustained a perioperative infarction, but the over-all mortality rate was similar in patients with or without infarction. There has been a recurrence rate of angina of approximately 5% per annum; however, in our more recent experience, 82% of our patients were alive and free of angina two years after surgery.

Adult↗
PubMed1981

Use of lignocaine and atropine autoinjectors for patients at high risk of sudden death and reinfarction after myocardial infarction.

Twenty-five patients entered a prospective study to assess the usefulness of atropine and lignocaine autoinjectors for coronary events after discharge from hospital after a definite, complicated myocardial infarction. They were selected on the basis of being at high risk of sudden death and reinfarction, being less than 70 years of age and being able to maintain a close liaison with the hospital. One or both autoinjectors were used for five reported events (four of collapse, one of chest pain) in four patients, with possible benefit in two instances. Six patients collapsed and died, despite the use of autoinjectors in three of their fatal collapses. In our experience, the use of autoinjectors has been of little observable benefit, perhaps due to the lack of specific warning symptoms preceding the onset of lethal arrhythmias, so that the injectors were often used for unobserved collapses when the chances of survival were remote.

Aged↗
PubMed1981

Patient initiated implantable pacemakers for paroxysmal supraventricular tachycardia.

Seven patients with recurrent paroxysmal supraventricular tachycardia (PSVT) resistant to standard drug therapy were treated with patient initiated implantable pacemakers. All patients had required frequent hospital admissions and cardioversions prior to pacemaker implantation. Two patients had Wolff-Parkinson-White (WPW) syndrome on their surface ECGs and five patients had no ECG evidence of preexcitation. All patients had detailed electrophysiological studies. Three patients had junctional tachycardia, one patients had reciprocating atrial tachycardia and in three, including one with normal surface ECG, retrogradely conducting accessory atrio-ventricular connections (AAVC) formed a part of the tachycardia circuit. Initiation and termination of tachycardia were re-checked at subsequent studies. On the basis of these studies, two patients with WPW syndrome had right ventricular endocardial leads and custom-built, magnet actuated pacemakers capable of delivering right ventricular coupled stimuli at fixed, present intervals of 200 and 400 ms. Both these pacemakers provided inconsistent reversions and proved unsatisfactory. In the remaining five patients, a unipolar tined J-shaped right atrial (RA) lead (Medtronic 6991) and a radiofrequency (RF) receiver (Medtronic 5998T) were implanted and enabled patients to overdrive ranged from 14 to 20 months. Several episodes of PSVT have been consistently reverted and none have required hospitalisation or cardio-version. Two patients had transient atrial fibrillation following the application of RF pacemaker. Three have required no antiarrhythmic drugs and in two the drug therapy has been greatly reduced and simplified. The Medtronic 6991 lead provided satisfactory RA stimulation without dislodgement. In carefully selected patients with PSVT, RF pacemakers provide a useful mode of treatment.

Adult↗
PubMed1980

An experimental study of the relationship between synergistic wound sepsis and suture materials.

In wounds on the back of guinea-pigs an inoculum of 6 x 10(5) of Escherichia coli and of Bacteroides fragilis produced a frank infection rate of 27 per cent. Addition of a catgut or a braided nylon tie statistically significantly increased the rate to 56 and 48 per cent respectively. Prolene and silk produced much smaller, non-significant rises. The rate with polyglycolic acid was 18 per cent which, though not statistically significant, suggests the possibility that this material produces conditions unfavourable to multiplication of bacteria that produce this type of infection.

Animals↗