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Biomedical subjects

R G Gold

Publications and source records attributed to R G Gold.

At least 19 recordsLinked to original sources
PubMed1997

A study comparing VVI and DDI pacing in elderly patients with carotid sinus syndrome.

OBJECTIVE: To determine whether single chamber ventricular demand (VVI) pacing is adequate for elderly patients with carotid sinus syndrome. DESIGN: Prospective double blind randomised cross over study. SETTING: Tertiary referral centre. PATIENTS: 30 consecutive patients aged over 60 years with carotid sinus syndrome referred for cardiac pacing. INTERVENTION: Patients underwent dual chamber pacemaker implantation and were then randomised to two three-month periods of VVI and DDI pacing. MAIN OUTCOME MEASURES: Responses to cardiovascular tests (vasodepression during carotid sinus massage, pacemaker effect, postural blood pressure measurements, and response to head up tilt), and symptoms. RESULTS: 11 patients developed profound hypotension during upright carotid sinus massage while pacing VVI compared with only two while pacing DDI. The upright pacemaker effect was greater in VVI (VVI, -31 (SD 19) mm Hg v DDI, -4 (12) mm Hg; P < 0.001). Postural blood pressure measurements and responses to head up tilt did not vary. Eleven patients were unable to tolerate VVI pacing and had to be withdrawn early from this limb of the study (group A). Fourteen of the remainder completed diary cards and did not express a preference (group B). No patient preferred VVI. Group A patients were older (group A, 78 (6) years v group B, 70 (9) years; P < 0.05), were more likely to be female (group A, 73% v group B, 14%; P < 0.01), and were more likely to have orthostatic hypotension while pacing DDI (group A, 46% v group B, 0%; P < 0.01). Group A and B patients could not be differentiated by other prepacing clinical or haemodynamic variables. CONCLUSIONS: Elderly patients with carotid sinus syndrome are likely to develop symptomatic hypotension following VVI pacing. The optimum pacing mode for individual patients cannot be predicted by simple cardiovascular tests before pacing.

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PubMed1996

Long-term thresholds of nonsteroidal permanent pacing leads: a 5-year study.

The present commercial market supports many nonsteroidal endocardial pacing leads of differing construction. In order to compare the performance of these configurations, we studied the long-term pacing properties of three representative lead types by randomized clinical trial in 99 patients undergoing a first elective VVI implant. Thirty-one patients received sintered platinum leads, 36 activated pyrolytic carbon leads, and 32 vitreous carbon leads. All received generators capable of noninvasive threshold testing. Acute sensing parameters were R wave amplitude and ST segment elevation measured from the endocardial electrogram. Noninvasive voltage thresholds were measured at implantation, 2 days, 1, 3, and 6 months, and yearly thereafter for 5 years. There were no significant differences between leads in pacing or sensing capabilities at implantation. All three demonstrated similar increases in thresholds, peaking at 1 month, then falling to a plateau by 6 months and did not vary significantly thereafter. There were no significant differences in thresholds between leads during 5 years of follow-up. The lowest mean threshold at 5 years was 0.93 V at 0.5 ms. This study suggests that: (1) although these lead types all perform well, none offers any particular clinical advantage over another; (2) the degree of early threshold peaking precludes immediate postimplant output reduction, but later thresholds are sufficiently low to enable reductions in pacing output; (3) safe low energy pacing requires greater attention to the lead-generator combinations; (4) data obtained at subsequent annual follow-up provided no additional useful clinical information to that obtained at 1 year; and (5) in the absence of other differences, cost can be the deciding factor in lead selection.

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PubMed1995

A randomized controlled clinical study to quantify the effect of small changes in the design of pacing electrodes on threshold voltages.

A double-blind randomized study of three pacing leads, identical in all ways except for the surface of their electrodes, is presented. The leads were implanted in 30 patients. Ten patients (Group A) received a standard Laserdish lead (dish electrode with laser pores), 10 patients (Group B) received a platinum-iridium coated modified Laserdish electrode, and 10 patients (Group C) received a platinum-iridium coated dish electrode identical to that in Group B except for the absence of laser pores. All leads were implanted by the same operator via the subclavian vein and all patients received an Optima MPT pulse generator. Direct measurement at implantation of pacing threshold and endocardial electrograms showed no significant difference between the three groups (mean +/- standard deviation voltage thresholds 0.30 +/- 0.06 V at 0.5 ms and 0.21 +/- 0.05 V at 1.0-ms pulse durations, R wave amplitude 7.6 +/- 3.2 mV). Significant differences (P = 0.001) were found in threshold impedances at implant (Group A 940 omega, Group B 782 omega, Group C 673 omega). Ten further measurements of voltage threshold were made over the next 2 years. Overall, at a pulse duration of 1.0 ms, a significantly reduced (P < 0.025) threshold voltage was found for both the electrode with pores and platinum-iridium coating compared with pores alone (20%), and with pores and platinum-iridium coating compared with the coating alone (18%). There was no significant difference between using platinum-iridium alone or pores alone. We have shown that a controlled randomized study, using electrodes that are identical except for the characteristics being assessed, can enable effects of small differences in electrode design to be quantified.

Double-Blind Method↗
PubMed1994

Impact of internal audit on pacemaker prescription and the immediate costs of pacing in the northern region: towards implementation of the recommendations of the British Pacing and Electrophysiology Group.

BACKGROUND: In September 1990 a working party of the British Pacing and Electrophysiology Group recommended the routine use of physiological pacing systems in patients with bradycardia. An audit of the impact of these recommendations on pacemaker prescription in the Freeman Hospital between March 1990 and August 1991 has previously been reported. This paper considers the effect of that internal audit on subsequent pacemaker prescription from September 1991 to February 1993. PATIENTS AND METHODS: The records of 1228 patients who underwent first pacemaker implantation at the Freeman Hospital between March 1990 and February 1993 were audited retrospectively. The patient's age, indication for pacing, pacing mode, and cost of the generator and leads were recorded. The indications for pacing were sinus node dysfunction (24.9%) (including patients with coexistent sinus node dysfunction and atrioventricular block), atrioventricular block (57.2%), atrioventricular block and atrial fibrillation (12.2%), and carotid sinus syndrome (5.7%). There was an increase in carotid sinus syndrome (2.7% to 8.1%) between the two study periods but no other differences in the distribution of case mix or characteristics of patients. The cost of the working party's recommended optimal pacing mode was calculated from multiplication of the mean cost of the recommended unit over the second half of the study period by the number of patients who would have received that unit. RESULTS: Between March 1990 and August 1991 atrial pacing for sinus node dysfunction (AAI, AAIR, DDD, or DDDR) increased by 138% (from 25.0% to 59.6%), mainly because of increased use of AAI mode. Physiological pacing for atrioventricular block (DDD or VVIR) increased by 41% (from 17.0% to 24.0%), and VVIR pacing for atrioventricular block with atrial fibrillation increased by 111% (from 10.5% to 22.2%). After the internal audit (that is, between September 1991 and February 1993), physiological pacing for atrioventricular block increased by a further 126% (from 24.0% to 54.2%). Sixty three per cent of this increase was in the first six months after the internal audit. Pacemaker prescriptions in sinus node dysfunction and atrioventricular block with atrial fibrillation were unchanged (59.6% physiological pacing for sinus node dysfunction and 22.2% v 27.3% VVIR pacing for atrioventricular block with atrial fibrillation). These changes in practice were accompanied by an increase in the age of patients receiving physiological units. Costs of pacemaker hardware for the final six months of the audit (excluding carotid sinus syndrome) increased by 38% over the costs that would have accrued had pacing policy remained the same as for the initial six month period before the circulation of the recommendations of the working party. Adoption of the guidelines of the working party in full would lead to a further 66% increase in the costs of hardware. CONCLUSIONS: The principal effect of the recommendations of the working party alone was increased use of AAI pacing for sinus node dysfunction, with little change in the costs of hardware. The internal audit was followed by an increase in physiological pacing for atrioventricular block, and this has had important financial consequences. Internal audit was followed by closer adherence to the recommendations of the working party.

Aged↗
PubMed1994

Antibiotic prophylaxis in permanent pacemaker implantation: a prospective randomised trial.

BACKGROUND: Pacemaker pocket infection is a potentially serious problem after permanent pacemaker implantation. Antibiotic prophylaxis is commonly prescribed to reduce the incidence of this complication, but current trial evidence of its efficacy is conflicting. A large prospective randomised trial was therefore performed of antibiotic prophylaxis in permanent pacemaker implantation. The intention was firstly to determine whether antibiotic prophylaxis is efficacious in these patients and secondly to identify which patients are at the highest risk of infection. METHODS: A prospective randomised open trial of flucloxacillin (clindamycin if the patient was allergic to penicillin) v no antibiotic was performed in a cohort of patients undergoing first implantation of a permanent pacing system over a 17 month period. Intravenous antibiotics were started at the time of implantation and continued for 48 hours. The trial endpoint was a repeat operation for an infective complication. RESULTS: 473 patients were entered into a randomised trial. 224 received antibiotic prophylaxis and 249 received no antibiotics. A further 183 patients were not randomised but were treated according to the operator's preference (64 antibiotics, 119 no antibiotics); these patients are included only in the analysis of predictors of infection. Patients were followed up for a mean (SD) of 19(5) months. Among the patients in the randomised group there were nine infections requiring a repeat operation, all in the group not receiving antibiotic (P = 0.003). In the total patient cohort there were 13 infections, all but one in the non-antibiotic group (P = 0.006). Nine of the infections presented as erosion of the pulse generator or electrode, three as septicaemia secondary to Staphylococcus aureus, and one as a pocket abscess secondary to Staphylococcus epidermidis. Infections were significantly more common when the operator was inexperienced (< or = 100 previous patients), the operation was prolonged, or after a repeat operation for non-infective complications (principally lead displacement). Infection was not significantly more common in patients identified preoperatively as being at high risk (for example patients with diabetes mellitus, patients receiving long term steroid treatment), although there was a trend in this direction. CONCLUSIONS: Antibiotic prophylaxis significantly reduced the incidence of infective complications requiring a repeat operation after permanent pacemaker implantation. It is suggested that antibiotics should be used routinely.

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PubMed1993

Endocardial pacemakers in children: lead length and allowance for growth.

Permanent endocardial pacing in small children is feasible but is limited by two problems: sufficient extra lead has to be left within the heart to allow for growth and the excess has to be coiled behind the pacemaker, limiting the benefit from smaller generators. The required intravascular lead length in 120 children and adults was measured on posteroanterior chest X ray and was correlated with standing height. Measurements were made from the mid-point of the left clavicle to the apex of the right ventricle in a curve simulating the usual endocardial lead position. In 60 children, aged 2.0-15.9 years, intravascular lead length (range 15.5-29.0 cm) correlated well with height (0.83-1.70 m), r = 0.91. In 60 adults, mean age 54.9 years, intravascular lead length (25.5-35.6 cm) also correlated well with height (1.45-1.85 m), r = 0.71. In 20 adults the excess extravascular lead length, measured during pacemaker implantation via the subclavian route, was 15.1-33.7 cm and was inversely correlated with height. A child's eventual adult height can be predicted and, using our data, the extra length of lead necessary to allow for growth can be computed. Available endocardial pacing leads are usually 58- to 64-cm long. The excess extravascular lead is a major practical difficulty in children. Shorter leads would avoid the problem of excess lead and facilitate long-term pacing in small children.

Adolescent↗
PubMed1992

Impact of the recommendations of the British Pacing and Electrophysiology Group on pacemaker prescription and on the immediate costs of pacing in the Northern Region.

BACKGROUND: The report from the Working Party of the British Pacing and Electrophysiology Group recommends the use of more sophisticated pacemakers in most patients. These proposals were initially circulated in September 1990 and are likely to have major cost implications. Their impact on pacing practice and the immediate costs of pacemaker hardware in the Northern Region were retrospectively audited. METHODS: The pacing records of 550 patients undergoing a first pacemaker insertion at the Freeman Hospital between March 1990 and August 1991 were reviewed. The patient's age, indication for pacing, pacing mode, and the cost of generator and lead(s) were recorded. The cost was compared with the costs of pacing with the optimal and alternative modes recommended by the Working Party. The costs were calculated from the actual mean cost of the recommended unit over the 18 month period of study multiplied by the number of patients who would have received that unit. RESULTS: 96% of patients were paced for sinus node dysfunction, atrioventricular block, or atrioventricular block and atrial fibrillation. The mean (SD) ages of patients in each diagnostic group were: sinus node dysfunction 69.4 (14), sinus node disease and atrioventricular block 67.2 (17.6), atrioventricular block 73.9 (12.5), atrial fibrillation and atrioventricular block 74.0 (13.9), and carotid sinus hypersensitivity 74.6 (11.6) years. Over the 18 month audit period there was an increase in physiological pacing. AAI pacing in patients with sinus node dysfunction increased by 100% and DDD pacing in atrioventricular block increased by atrioventricular block increased by 56%. Over the whole 18 month period the adoption of the British Pacing and Electrophysiology Groups optimal recommendations would have increased expenditure on pacemaker hardware in the Northern Region by 94% and the use of the alternative mode would have increased it by 61%. For the last six months alone the excess would be 78% and 48%. CONCLUSIONS: The adoption of the recommendations of the British Pacing and Electrophysiology group in the Northern Region would greatly increase the cost of pacing hardware. The greater part of this increase would be attributable to the routine use of dual chamber pacing in patients with atrioventricular block and the increased use of rate responsive units. The benefits of sophisticated pacing in a predominantly elderly population need to outweigh the disadvantages of the increased cost and complexity of follow up.

Aged↗
PubMed1991

Complications associated with retained pacemaker leads.

Retention of functionless pacemaker leads may occur following mechanical or infective problems (potentially or definitely infected) or after electrical failure of the lead. One hundred nineteen patients with a pacemaker lead (or leads) retained between 1970 and 1990 were reviewed retrospectively. Lead retention after an intervention dictated by potential or definite infection of the pacing system resulted in complications in 27 of 53 patients (51%), which in 22 patients (42%) were major (septicemia, superior vena cava syndrome, and further surgery under general anesthesia for recurrent "infective" problems) including three deaths. Complications were less likely if lead retention occurred after electrical failure with three minor and two major (surgery under general anesthesia, superior vena cava syndrome) complications in 66 patients (P less than 0.001). Bacteriology of swabs taken at the time of retention in the patients with potential or definite infection was unhelpful in predicting future complications: 8/18 patients (44%) whose swabs were negative had complications of which 5/18 (28%) were major. In our experience retention of functionless pacemaker leads after an intervention dictated by potential or definite infection of the pacing system, is associated with significant morbidity and mortality and should be avoided.

Adolescent↗
PubMed1990

Coxsackie B4 viral myocarditis causing ventricular aneurysm.

This report describes a patient with viral myocarditis who developed acute dilated cardiomyopathy. The patient recovered well but a left ventricular aneurysm was detected angiographically. There was no history of myocardial infarction and the coronary arteries were normal. This is the first reported case of left ventricular aneurysm due to viral myocarditis.

Adult↗
PubMed1989

Do electrode and lead design differences for permanent cardiac pacing translate into clinically demonstrable differences? (Comparison of sintered platinum and activated vitreous and porous carbon electrodes).

A randomized prospective study was undertaken to compare the electrical performances of three permanent, endocardial, tined pacing leads with different electrode designs--sintered platinum, vitreous carbon, and porous carbon. Ninety-nine patients received one of the leads (S80 31; 423S 32; S100 36). Acute R wave amplitude and ST elevation of the native endocardial electrogram, voltage threshold, impedance, and current flow at four pulse durations (0.25-1.0 msec) were measured. Voltage thresholds were measured noninvasively at each of four pulse durations at 2 days and 1, 3, and 6 months after implantation. No significant differences were found in sensing properties, or current flow at threshold at 0.5 msec pulse duration. The 423S lead had a significantly higher impedance at threshold and both a higher impedance and lower current flow at 5 V. No significant differences in threshold voltages were found between the three leads at any pulse duration, at any of the assessed times after implantation. Six-month thresholds for the S80, 423S, and S100 leads were 1.18 +/- 0.35, 1.17 +/- 0.29, and 1.06 +/- 0.38 V respectively at 0.5 msec pulse duration. Differences between 'high performance' pacing leads need to be of a greater order of magnitude before they can be exploited to give any real clinical advantage to patients.

Aged↗
PubMed1988

Convergent validity of the Child Abuse Potential Inventory.

The convergent validity of the Child Abuse Potential Inventory (CAP) was investigated (N = 254). Because the CAP was designed to measure elements of individual pathology and interactional problems related to physical child abuse, it was predicted that CAP scores would be related to a measure of psychological status, the Mental Health Index (MHI). Specifically, it was predicted that the CAP would be correlated positively with MHI measures of psychological distress and, to a lesser degree, correlated inversely with MHI measures of psychological well-being. Because the CAP measures variables predictive of abusive behavior, a substantial relationship was expected between the CAP and the MHI Loss of Behavioral/Emotional Control scale. All hypotheses were supported.

Adult↗
PubMed1988

Minimum energy for cardiac pacing.

Conditions for minimum energy pacing of the heart have been investigated. A total of 99 patients undergoing permanent cardiac pacing with one of three different leads were studied. Measurements of threshold voltage and current flow were made at 0.25, 0.5, 0.75, and 1.0 ms pulse durations. All measurements were made directly from the lead at implantation. There were no significant differences in threshold energy between the three leads used, and therefore all 99 leads were pooled for further analysis. There were significant differences (P less than 0.05) between the pacing energies required at the four pulse durations; the mean threshold energy at 0.25 ms was 156 nJ, at 0.5 ms 115 nJ, at 0.75 ms 110 nJ, and at 1.0 ms 102 nJ. Significant energy savings may be achieved when programming pacemakers to the optimum output for each patient by reducing pacemaker voltage - current output in preference to reducing pacing pulse duration.

Aged↗
PubMed1987

"Are the differences between 'high performance' pacing leads clinically significant? A comparison of sintered platinum and activated carbon".

A retrospective assessment was performed of the acute implantation characteristics of two pacing leads, one with a sintered platinum (S 80-T) electrode and the other with an activated vitreous carbon (412-S) electrode in 124 patients. The S80-T lead had a significantly lower implantation threshold. The differences between the two leads in sensing properties, in current flow at threshold voltage and at the output of the generator were not significant at implantation. The 412-S lead had a higher impedance measurement than the S-80-T at implantation but this was mainly due to the resistance differences of the conductors rather than to electrode-patient interactions. A subgroup of 20 patients had chronic threshold measurements. The S 80-T lead had a significantly lower chronic voltage threshold. However because the acute and chronic differences are small we conclude that, although these differences are statistically significant, they are not clinically significant. Both can justifiably be termed 'high-performance' leads.

Adult↗
PubMed1986

Screening spouse abusers for child abuse potential.

This study investigated the ability of the Child Abuse Potential (CAP) Inventory to screen for child abuse in a group of spouse abusers. Eighty-seven untreated male spouse abusers and 95 nonabusers were administered the CAP Inventory. All of the subjects were active duty, United States military personnel. The completed, valid protocols revealed that 36.5% of the spouse abusers had elevated child abuse scores, while only 9.1% of the nonabusers had elevated abuse scores. An analysis of variance indicated that the spouse abusers had significantly higher mean abuse scores. Four concurrent reports of child abuse were made in the spouse abuse group. Two of these spouse/child abusers had valid protocols, and both scored significantly higher than those spouse abusers with no reported child abuse. The finding that over 36% of the spouse abusers had elevated child abuse scores supports Walker's (1979) finding that one-third of spouse abusers are child abusers. A limitation in this study is that no longitudinal data were obtained to determine whether those with elevated child abuse scores who were not reported for child abuse subsequently would abuse their children.

Adult↗
PubMed1985

Child abuse potential and authoritarianism.

This study examined the relationship between child abuse, as measured by the Child Abuse Potential (CAP) Inventory, and authoritarianism, as measured by the Public Opinion Scale (POS). The study also attempted to provide convergent and discriminant validity for the CAP abuse factors rigidity and loneliness by correlating these factors with the Edwards Personal Preference Schedule (EPPS) variables order and affiliation, respectively. Group One consisted of 150 undergraduate students. Group Two consisted of 34 adult students from a second site. For the subjects in both groups, a nonsignificant relationship (p greater than .05) between abuse scores and authoritarianism was found. In contrast, in both groups significant relationships (p less than .05) were found between the CAP abuse factor rigidity and authoritarianism. Additional analysis indicated a significant inverse relationship (p less than .05) between the EPPS variable affiliation for Group One, but not for Group Two (p greater than .05).

Adult↗