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Biomedical subjects

G D Cope

Publications and source records attributed to G D Cope.

10 recordsLinked to original sources
PubMed1992

Use of twenty-four hour infusions of intracoronary tissue plasminogen activator to increase the application of coronary angioplasty.

Coronary arteries occluded by long lengths of thrombus are usually considered unattractive for angioplasty. Nine patients (8 male, mean age 50.1 years) undergoing angiography for unstable angina were found to have single vessel disease considered unsuitable for angioplasty as the vessel was occluded by a long length of thrombus. These patients were treated with 24 hr intracoronary infusions of 100 mg tPA in an attempt to make angioplasty feasible. Marked thrombolysis occurred in 7 patients who received uncomplicated infusions. One case was unsuccessful due to catheter displacement, while another had the infusion ceased due to an intracerebral bleed from a previously silent A-V malformation. This was the only major complication. Angioplasty was attempted in 6 of 7 cases where lysis had been achieved, with success in all lesions attempted. This reports shows that intracoronary tPA infused over prolonged periods produces excellent thrombolysis, making angioplasty feasible in some patients who were previously unsuitable.

Angina, Unstable↗
PubMed1991

Effects of low-dose aspirin on restenosis after coronary angioplasty.

After angioplasty of a previously untreated native coronary artery and after 2 weeks of aspirin therapy, 216 subjects (aged less than 70 years without acute infarction) were randomized to treatment with soluble aspirin, 100 mg/day, or placebo to study the effect on restenosis. Follow-up, defined as angiography at 6 months, earlier angiographic restenosis or coronary bypass surgery was completed by 108 aspirin- and 104 placebo-treated patients. Restenosis (stenosis greater than or equal to 50% plus loss of greater than or equal to 50% of gain, or surgery) occurred in 38 (35%) aspirin- and 45 (43%) placebo-treated subjects (p = not significant). No patient died. Restenosis occurred in 42 of 168 (25%) aspirin- and 51 of 135 (38%) placebo-treated lesions (p less than 0.025). Aspirin-treated lesions (n = 163) had lost 16 +/- 22% (mean +/- standard deviation) of lumen and placebo-treated lesions 22 +/- 25% of lumen (n = 134) at angiography (p less than 0.01). There were more left anterior descending lesions in the placebo group and these had a higher recurrence rate than other lesions. The beneficial effect of aspirin was not dependent on this, although significance was reduced in subgroup analysis. Loss of lumen in left anterior descending lesions was 20 +/- 24% (n = 57) in the aspirin-treated and 27 +/- 25% (n = 70) in the placebo-treated lesions (p less than 0.1). It is concluded that there is a small beneficial effect of low-dose aspirin on restenosis after coronary angioplasty.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Comparison of meglumine sodium diatrizoate, iopamidol, and iohexol for coronary angiography and ventriculography.

Meglumine sodium diatrizoate (Urografin), iopamidol, and iohexol were compared in a double-blind, randomized study of 287 patients undergoing elective cardiac angiography. Ninety-six patients received Urografin, 98 received iopamidol, and 92 received iohexol. The groups were similar in all respects. Variables measured before and after contrast injection were left ventricular end-diastolic pressure (LVEDP), left ventricular systolic pressure (LVSP), systolic arterial pressure (SAP), RR, PR, and QTc intervals, QRS duration, ST segment change greater than 2 mm, arrhythmias, and symptoms. The adequacy of coronary and ventricular opacification was assessed by two experienced observers. Following left ventriculography, small rises in LVEDP occurred with iopamidol and iohexol (mean +/- SD: 18 +/- 7 to 21 +/- 7 mmHg) and a moderate fall in LVSP with Urografin (150 +/- 32 to 133 +/- 32 mmHg). Following coronary angiography there was a progressive fall in SAP (130 +/- 26 to 117 +/- 30 mmHg) and prolongation of RR intervals (900 +/- 138 to 1,266 +/- 692 msec) and QTc (440 +/- 61 to 471 +/- 73 msec) and QRS duration (87 +/- 25 to 100 +/- 27 msec) with Urografin. There was a small fall in SAP with iopamidol (138 +/- 25 to 128 +/- 27 mmHg) and prolongation of QRS duration with iohexol (85 +/- 29 to 90 +/- 24 msec). Other parameters were not significantly affected. Frequent bradyarrhythmias (sinus pause 14.5%, asystole 6%) and ST segment depression occurred following Urografin. Urografin was less well tolerated, with 10% of patients experiencing severe nausea or vomiting and 30% of patients experiencing extreme heat sensation. Differences between iohexol and iopamidol were minor.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiography↗
PubMed1989

Long term efficacy of transvenous catheter ablation of the atrioventricular junction for refractory supraventricular tachycardia.

Twenty-four patients who underwent transvenous catheter ablation of the atrioventricular (A-V) junction between November 1982 and February 1987 were followed from 18-72 months (mean 47.9) to assess the long term efficacy and safety of the procedure. All had severely symptomatic supraventricular tachyarrhythmias refractory to standard treatment. Atrioventricular conduction was abolished in 23 patients, 22 having permanent pacemakers implanted. Conduction has recovered, though it is modified, in one patient who is asymptomatic on digoxin. Four patients have died; one suddenly 20 months following the procedure, one of progressive heart and liver failure due to hemochromatosis, and two of a stroke. Four patients have had complications related to permanent pacing; one patient has required generator replacement and one patient ventricular lead replacement, one patient had asystole and one patient had a pacemaker-related tachycardia. Two patients remain symptomatic but improved by the procedure. Seventeen patients are free of their original symptoms, 11 having no intervening morbid events. These results demonstrate that patients with severely symptomatic supraventricular tachyarrhythmias may gain long term symptomatic relief from the procedure, but permanent pacing is a cause of significant morbidity and there is a small incidence of late sudden cardiac death.

Adult↗
PubMed1985

Initial experience with physiological pacing.

Fifty patients, aged 23 to 88 years, with permanent rate-responsive dual chamber pacemakers were studied prospectively for 14.1 +/- 11.4 (S.D.) months after implantation to assess the benefits and complications associated with this technique. In 12 patients the device replaced a ventricular demand pacemaker. Minor complications associated with implantation occurred in one case. Atrial leads required repositioning because of increase in threshold and/or problems of sensing in five cases and ventricular leads in five. There were two patients with symptomatic pacemaker-related arrhythmias necessitating reprogramming; one patient with pacemaker-mediated tachycardia and one with pacemaker autoinhibition. Seven patients have died; one suddenly and possibly related to a pacemaker-triggered arrhythmia. Of 43 living patients, five are now programmed to the ventricular demand mode; two with atrial fibrillation, one with failed atrial lead repositioning, one with persistent sinus tachycardia, and one because of angina pectoris. Thirty-six of the 43 living patients are asymptomatic and a further six are symptomatically improved. All 12 patients changed from ventricular demand pacing have less symptoms. Rate-responsive dual chamber pacing is safe and appears to improve symptoms in most cases. Complications are infrequent and usually easily overcome. This mode of pacing should be considered in all patients with normal sinoatrial function in whom a permanent pacemaker is indicated.

Adult↗
PubMed1976

Retrograde atrial preexcitation following premature ventricular beats during reciprocating tachycardia in the Wolff-Parkinson-White syndrome.

In 34 successive patients with Wolff-Parkinson-White syndrome premature beats were induced from the right ventricular apex during reciprocating tachycardia (RT) at progressively shorter coupling intervals. The presence of an accessory pathway was confirmed by a reduction in the atrial cycle length (A-A interval) during which the premature ventricular beat was introduced. This retrograde preexcitation occurred at a time when the His-AV node pathway was refractory; i.e. there was premature activation of the atria over a pathway other than the His-AV node. 3 patients were excluded because of unsatisfactory or unstable H-H intervals. In the remaining 31 patients with constant preceding H-H intervals, the A-A interval shortened; (a) 35-65 msec in 4 patients with right-sided pathways and normal conduction during RT and by 110 msec in a 5th patient with a right-sided pathway, in whom bundle branch block aberration persisted during RT, (b) 45 msec in the single patient with both a right-sided and a septal accessory pathway, (c) 35-65 msec in 5 patients with septal pathways, and (d) 15-35 msec in only 4/20 patients with left-sided pathways and normal conduction during RT. Left-sided ventricular premature beats were introduced in 5 patients with left-sided pathways and normal conduction in RT. In 4/5, left-sided premature beats shortened the A-A interval 40-75 msec whereas right-sided premature beats at the same coupling interval failed to do so. In the fifth case, the left-sided premature resulted in a 65 msec abbreviation of the A-A interval compared to 30 msec from the right ventricular outflow tract and 15 msec from the right ventricular apex. In 5 patients with left-sided pathways, right ventricular premature beats were introduced during RT with left bundle branch block aberration, and shortened the A-A interval 30-50 msec in all of these, whereas right-sided premature beats in 4 of the 5 during normal conduction failed to do so. This technique is useful to confirm the participation of accessory pathways in reciprocating tachycardias associated with the preexcitation syndromes, and emphasizes the importance of the site of stimulation used relative to the location of the accessory pathway. Because of the possibility of multiple accessory pathways, stimulation of the left ventricle should be performed in patients undergoing surgery for preexcitation unless the left ventricle is already inplicated by right-sided studies.

Adolescent↗
PubMed1975

Diastolic vibration of the interventricular septum in aortic insufficiency.

The echocardiograms of 46 patients with aortic insufficiency which manifested typical high frequency vibrations of the anterior mitral valve leaflet were reviewed. All patients had overt clinical evidence of aortic insufficiency which was confirmed by angiography in 17 cases. In 17 cases (eight of whom underwent catheterization and angiography), high frequency diastolic vibrations of the interventricular septum of similar frequency to those on the anterior mitral leaflet were observed. This finding was not seen in 100 control echocardiograms from patients without clinical evidence of aortic insufficiency, and represents a previously undescribed echocardiographic manifestation of this lesion.

Adolescent↗
PubMed1975

A reassessment of the echocardiogram in mitral stenosis.

Echocardiographic and cardiac catheterization findings were compared in 61 patients with mitral stenosis without other significant lesions in an attempt to determine the clinical usefulness of echocardiography in the assessment of such patients. There was a poor correlation between the E-F slope on the echocardiogram and the calculated mitral valve area (r = 0.51). A review of reported data relating the E-F slope to mitral valve area indicated that echocardiographic assessment of mitral valve area had low sensitivity and specificity. The amplitude of excursion of the anterior leaflet did not differ significantly in patients undergoing valvotomy and those undergoind valve replacement. The data obtained suggest that while the echocardiogram is a reliable method of diagnosing mitral stenosis, the E-F slope is an unreliable index of the severity of the lesion.

Adult↗
PubMed1975

Initial forces of ventricular depolarization in the Wolff-Parkinson-White Syndrome. Analysis based upon localization of the accessory pathway by epicardial mapping.

The epicardial activation sequence of 34 patients with the Wolff-Parkinson-White syndrome was determined. Epicardial pre-excitation occurred at a spectrum of sites over either the free wall of the left or right ventricle or in a paraseptal region, always adjacent to the atrioventricular rings. The site of pre-excitation was related to the spatial position of the 10 msec vector of the vectorcardiogram (VCG) in 15 patients and the 20 msec vector of the electrocardiogram (ECG) in 29 patients with a single accessory pathway. All patients whose 20 msec vector (ECG) was directed to the right had accessory pathways which caused epicardial breakthrough over the free wall of the left ventricle. When the 20 msec vector (ECG) was to the left and inferior, epicardial pre-excitation was over either the right ventricular free wall or in the region of the pulmonary outflow tract. Superior location of the initial forces, especially the 10 msec vector (VCG), strongly suggested the presence of a septal bypass tract. The polarity of the delta wave and maximum QRS forces in precordial lead V1 were discordant in a significant number of patients, pointing to probable shortcomings of a classification based upon the latter.

Adolescent↗