Adult coronary artery disease secondary to childhood Kawasaki disease.
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Adult↗
Biomedical subjects
A F Rickards
Publications and source records attributed to A F Rickards.
Quantitative angiographic follow-up of the coronary Wallstent in native vessels and bypass grafts (European experience--March 1986 to March 1990).
The coronary stent has been investigated as an adjunct to percutaneous transluminal coronary angioplasty to obviate the problems of early occlusion and late restenosis. From March 1986 to March 1990, 265 patients (308 lesions) were implanted with the coronary Wallstent in 6 European centers. For this study, the patients were analyzed according to date of implantation (group 1, March 1986 to January 1988; group 2, February 1988 to March 1990) and vessel type (native arteries versus bypass grafts). Quantitative angiographic follow-up was performed in 82% of the study patients. The early in-hospital occlusion rate in the overall group was 15%. Group 1 patients had a 20% rate in contrast to 12% rate in group 2 (p = not significant [NS]). The early occlusion rate in native vessels and bypass grafts was 19 and 8%, respectively (p = 0.019). Restenosis was determined by 2 criteria (criterion 1, greater than or equal to 0.72 mm loss in minimal luminal diameter from poststent to follow-up; criterion 2, greater than or equal to 50% diameter stenosis at follow-up) within the stent and in the segments immediately proximal and distal to the stent. The restenosis rate with criterion 1 was 43% in the overall group of patients, 35% in group 1 versus 49% in group 2 (p = NS), and 34% in native vessels versus 54% in bypass grafts (p = 0.016). The second criterion was met by 27% of patients in the overall group, 21% in group 1 versus 32% in group 2 (p = NS), and 18% in native vessel versus 39% in bypass grafts (p = 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)
Actuarial Analysis↗
Rate-responsive pacing using electrographic parameters as sensors.
The use of evoked QT-interval and ventricular depolarization gradient as sensors for rate-responsive pacing is described in this article. The QT interval has been used as a biosensor in implantable pacemakers since 1981, and recent refinements have improved the rate response characteristics and simplified the programming of this pacemaker. Recently, QT and activity sensing have been combined to produce a dual-sensor rate-responsive pacemaker that may offer advantages over single-sensor devices. The ventricular depolarization gradient has been incorporated into a closed-loop rate-responsive pacing system and is undergoing clinical evaluation.
Electrocardiography↗
Outcome following incomplete revascularisation by coronary balloon angioplasty in patients with multivessel coronary artery disease.
When performing coronary angioplasty in patients with multivessel disease, there is an increasing trend to attempt balloon dilation of only ischaemia producing coronary stenoses (a strategy generally associated with incomplete revascularization) rather than attempting to dilate all anatomically significant stenoses (complete revascularization strategy). However the clinical efficacy of the former strategy has been questioned. To explore further this issue, we reviewed the records of 64 consecutive patients with multivessel coronary artery disease undergoing their first angioplasty at our centre in the 15 month period, October 1st 1987 to December 31st 1988. In 59 of these 64 patients, a strategy of incomplete revascularisation [attempted dilation of at least one stenosis > or = 70% but with one or more residual stenoses > or = 70% that were not attempted] was pursued. Of these 59 patients, 18 (31%) has three vessel coronary artery disease [stenoses > or = 70% in all three major coronary artery territories] and 19 (32%) had undergone previous coronary bypass surgery. In all 59 patients, prior to angioplasty, it was attempted to identify the ischaemia producing (so-called 'culprit') lesion(s). In the 59 patients, 66 culprit lesions in 63 vessels were identified. At angioplasty, in all patients, attempted dilation was confined to the culprit lesion(s). Clinical success (successful dilation of all attempted lesions without the occurrence of in-hospital myocardial infarction, death, or coronary bypass surgery) was achieved in 53 (90%) patients. At one year following successful angioplasty, no patient had died or suffered a myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Angiographic follow-up after placement of a self-expanding coronary-artery stent.
BACKGROUND: The placement of stents in coronary arteries after coronary angioplasty has been investigated as a way of treating abrupt coronary-artery occlusion related to the angioplasty and of reducing the late intimal hyperplasia responsible for gradual restenosis of the dilated lesion. METHODS: From March 1986 to January 1988, we implanted 117 self-expanding, stainless-steel endovascular stents (Wallstent) in the native coronary arteries (94 stents) or saphenous-vein bypass grafts (23 stents) of 105 patients. Angiograms were obtained immediately before and after placement of the stent and at follow-up at least one month later (unless symptoms required angiography sooner). The mortality after one year was 7.6 percent (8 patients). Follow-up angiograms (after a mean [+/- SD] of 5.7 +/- 4.4 months) were obtained in 95 patients with 105 stents and were analyzed quantitatively by a computer-assisted system of cardiovascular angiographic analysis. The 10 patients without follow-up angiograms included 4 who died. RESULTS: Complete occlusion occurred in 27 stents in 25 patients (24 percent); 21 occlusions were documented within the first 14 days after implantation. Overall, immediately after placement of the stent there was a significant increase in the minimal luminal diameter and a significant decrease in the percentage of the diameter with stenosis (changing from a mean [+/- SD] of 1.88 +/- 0.43 to 2.48 +/- 0.51 mm and from 37 +/- 12 to 21 +/- 10 percent, respectively; P less than 0.0001). Later, however, there was a significant decrease in the minimal luminal diameter and a significant increase in the stenosis of the segment with the stent (1.68 +/- 1.78 mm and 48 +/- 34 percent at follow-up). Significant restenosis, as indicated by a reduction of 0.72 mm in the minimal luminal diameter or by an increase in the percentage of stenosis to greater than or equal to 50 percent, occurred in 32 percent and 14 percent of patent stents, respectively. CONCLUSIONS: Early occlusion remains an important limitation of this coronary-artery stent. Even when the early effects are beneficial, there are frequently late occlusions or restenosis. The place of this form of treatment for coronary artery disease remains to be determined.
Angiography↗
Successful intracardiac electrical conversion of atrial flutter in patients with complex congenital heart disease.
Sixteen patients presenting on 21 occasions with atrial flutter in association with complex congenital heart disease were treated by intracardiac stimulation techniques combined with activation mapping. Nineteen episodes of atrial flutter were successfully converted to sinus rhythm. In the remaining two episodes atrial fibrillation was induced with spontaneous conversion to sinus rhythm within 12 hours in one episode and immediate DC cardioversion to sinus rhythm in the other. Intracardiac stimulation techniques were highly successful in this group and allowed reliable conversion to sinus rhythm without general anaesthesia and high energy cardioversion. In patients with atrial flutter associated with congenital heart disease intracardiac stimulation techniques should be tried first.
Adolescent↗
Outcome of extensive coronary artery dissection during coronary angioplasty.
A total of 32 (3.6%) patients of 880 undergoing coronary angioplasty during a nine year period at one hospital had extensive dissection (defined as a dissection extending beyond the limits of the dilated angioplasty balloon) in the coronary artery in which the angioplasty procedure was performed. Two (6.25%) of the 32 patients (both of whom were undergoing angioplasty because of unstable angina that was refractory to medical treatment) died as a consequence of the coronary artery dissection. Twelve (38%) needed immediate coronary artery bypass surgery and 11 (34%) had a myocardial infarction, which in four was minor in extent. During follow up, 20 of the 32 patients were successfully managed by medical treatment; only two needed further angioplasty procedures. There were no late deaths. Extensive coronary artery dissection is a serious complication of coronary angioplasty, with a high early mortality and a high incidence of infarction and requirement for bypass surgery. None the less, patients with extensive dissection who are free from the manifestations of acute ischaemia at the end of the procedure can be managed conservatively and have a good immediate and medium term outlook. Attempts should be made to stabilise extensive dissection during coronary angioplasty so that surgical intervention can be delayed or avoided altogether if possible.
Adult↗
Relative risk analysis of angiographic predictors of restenosis within the coronary Wallstent.
BACKGROUND: Late angiographic narrowing has been observed following coronary implantation of the Wallstent. To identify the angiographic variables that predict restenosis within the stented segment, a retrospective study of data from the European Wallstent core laboratory was performed. METHODS AND RESULTS: Follow-up angiograms (excluding patients with in-hospital occlusions) were analyzed for 214 lesions in 176 patients (78% restudy rate). The incidence of restenosis within the stented segment was 35% by lesion and 35% by patient for criterion 1 (greater than or equal to 0.72 mm loss in minimal luminal diameter) and 24% by lesion and 24% by patient for criterion 2 (diameter stenosis greater than or equal to 50% at follow-up). The association between 16 variables and restenosis was determined by a relative risk ratio assessment. Variables with significant risk ratios for restenosis with criterion 1 were use of multiple stents/lesion (relative risk, 1.56; 95% confidence interval [CI], 1.08-2.25) and oversized (unconstrained stent diameter exceeding reference diameter greater than 0.7 mm) stents (relative risk, 1.64; 95% CI, 1.10-2.45), and for criterion 2, oversizing by more than 0.70 mm (relative risk, 1.93; 95% CI, 1.13-3.31), bypass grafts (relative risk, 1.62; 95% CI, 0.98-2.66), use of multiple stents/lesion (relative risk, 1.61; 95% CI, 0.97-2.67) and residual diameter stenosis more than 20% post stenting (relative risk, 1.51; 95% CI, 0.91-2.50). CONCLUSIONS: It is concluded that several angiographic variables are significantly associated with late angiographic narrowing after stenting in the coronary arteries. We suggest that stent operators avoid excessive oversizing in the selection of stent diameter and the use of multiple stents per lesion to lessen the risk of late restenosis.
Blood Vessel Prosthesis↗
Familial restrictive cardiomyopathy with atrioventricular block and skeletal myopathy.
Five generations of an Italian family with an autosomal dominant restrictive cardiomyopathy are described. Members of four generations were examined. Symptoms usually developed in the third or fourth decade but the disease did occur in childhood. Initially the condition was characterised by normal ventricular size and systolic function with increased diastolic filling pressures in both ventricles and consequent bi-atrial enlargement. Cardiac catheterisation showed a left ventricular filling pattern of "dip and plateau". The electrocardiogram typically showed non-specific changes in the ST segment and T wave and changes indicating considerable atrial enlargement, which were confirmed by echocardiography. Light microscopy of two endocardial biopsy specimens showed no specific features but excluded the endomyocardial fibrosis of eosinophilic heart disease, amyloid, and specific heart muscle diseases. At necropsy in one case examined under light microscopy extensive patchy fibrosis was found throughout the endocardium, myocardium, and subepicardium, but there were no features typical of eosinophilic heart disease. Histopathological and biochemical examination of skeletal muscle identified no abnormality. The disease often had an insidious course over five to ten years after presentation. Bundle branch blocks, leading to complete atrioventricular block, however, often occurred and may be the first manifestation. Some individuals who survived into the fifth decade developed a progressive, non-wasting skeletal myopathy.
Adolescent↗
Aberrant origin of the right coronary artery as a potential cause of sudden death: successful anatomical correction.
A man with an aberrant right coronary artery and haemodynamically important prolapse of the mitral valve was successfully resuscitated. The aberrant right coronary artery was thought to be a possible cause of the cardiopulmonary arrest in this patient. Both lesions were corrected at a single operation.
Aged↗
Clinical outcome following coronary balloon angioplasty in 100 consecutive patients with multivessel coronary artery disease.
Prompted by current uncertainties regarding the precise role of percutaneous transluminal coronary balloon angioplasty (PTCA) in patients with multivessel disease, we reviewed the records of 100 such patients undergoing their first PTCA at our centre between 1 March 1987 and 23 March 1989. Thirty had three-vessel coronary disease (stenoses greater than or equal to 70% in all three major coronary artery territories), 51 had a previous myocardial infarction and 25 had undergone previous coronary bypass surgery. The mean number of lesions of greater than or equal to 70% per patient was 2.7 (0.8) [mean (SD)]. Successful angioplasty was achieved in 88 of these 100 patients. One year following successful angioplasty, the overall event-free rate [freedom from death, myocardial infarction, need for further revascularisation by either aortocoronary bypass graft surgery or repeat angioplasty, and recurrence of severe (class III/IV) angina] was 73%. These data suggest that, in patients with multivessel disease, angioplasty may be an effective technique for short-term symptomatic management. Definitive guidelines regarding the role of PTCA in such patients must await the results of ongoing large-scale clinical trials.
Adult↗
Impedance changes during catheter ablation and their relationship to electrical arcing and clinical efficacy.
This study has used high energy ablative shocks in saline and in man to characterize the complex, energy dependent behavior of the impedance at the electrode-tissue interface. In vitro shocks showed a fall in impedance when an arc was formed, due to formation around the electrode of a vapor globe rendered conductive by the arc. Following arc extinction, this same vapor globe insulates the electrode, and subsequently collapses, forming a shock wave, and allowing current flow to resume. Shocks delivered to tissue specimens exhibited progressively higher impedance and less insulation as contact pressure was increased. In vivo, lesser degrees of insulation during arcing shocks were associated with greater clinical efficacy.
Animals↗
Catheter ablation without fulguration: design and performance of a new system.
A new system is described for catheter ablation which comprises a short time capacitive power source and a specially designed catheter. The aim of the new system is to deliver high voltages with minimal or no arcing and thus avoid the risks associated with barotrauma. The performance of the new system was compared in a saline tank with that of the conventional system. The new system allowed significant increases in delivered voltage, current and energy without arcing. This new system should allow safer catheter ablation.
Electric Countershock↗
The automatic implantable cardioverter/defibrillator for a life threatening arrhythmia in a case of post-partum cardiomyopathy.
We report the development of severe life threatening polymorphic ventricular tachycardia in a young woman shortly following her first pregnancy, who ultimately required the insertion of an automatic implantable cardioverter/defibrillator because of the failure of conventional antiarrhythmic therapy. Although only about 7 patients have received units in the UK to date, the experience in the USA, where up to 300 per month may be implanted, suggests that they will become a more common method of treatment in cases of life threatening arrhythmias.
Adult↗
Additional improvement of stenosis geometry in human coronary arteries by stenting after balloon dilatation.
The purpose of this study was to assess the early changes in stenosis geometry after insertion of intravascular stents in human coronary arteries. Morphologic changes were evaluated by quantitative coronary angiography (using automated edge detection) and by calculation of the theoretical pressure decrease across the dilated and stented stenosis from the Poiseuille and turbulent resistances assuming a coronary blood flow of either 1 or 3 ml/s. Twenty-six patients were studied before and after angioplasty, as well as immediately after stent implantation. The stented coronary artery was the left anterior descending artery in 19 cases, the circumflex artery in 2 cases, the right coronary artery in 2 cases and a coronary artery bypass vein graft in 3 cases. After stent implantation, an additional increase in minimal luminal cross-sectional area of the dilated vessel was observed, suggesting that the self-expanding stainless steel endoprosthesis used in this study has a dilating function in addition to its stenting role.
Angiography↗
Early and late assessment of stenosis geometry after coronary arterial stenting.
Early and late modifications of stenosis geometry after stenting of coronary arteries were assessed. Morphologic changes were evaluated by quantitative coronary angiography (automated edge-detection) and theoretical pressure drop across the dilated and stented stenosis was calculated from the Poiseuille formula, with turbulent resistances assuming a coronary blood flow of 1 or 3 ml/s. Eleven patients (ages 41 to 69 years, mean 55) were studied before and after angioplasty, and immediately after stent implantation. The stented coronary artery was the left anterior descending artery in 9 patients and the left circumflex in 2. Following stent implantation, an additional increase in minimal luminal cross-sectional area of the dilated vessel was observed, suggesting that the self-expanding stainless-steel endoprosthesis used had a dilating function in addition to its stenting role. Repeat angiography in 6 patients 3 months after stent implantation showed a decrease in the minimal luminal cross-sectional area without a significant change in theoretic pressure decrease. This slight reduction in vessel caliber had no hemodynamically significant repercussions. Thus, stenting of coronary arteries following dilatation is a potentially valuable technique for preventing both abrupt closure and late reduction in lumen diameter.
Adult↗
Effects of intracoronary isosorbide dinitrate during acute myocardial ischaemia: a study during angioplasty.
The effects of isosorbide dinitrate on acute myocardial ischaemia were studied in 19 patients during coronary angioplasty. The duration of balloon inflation to the onset of ST segment depression was increased by the administration of intracoronary isosorbide dinitrate from (mean +/- SEM) 13 +/- 2 to 20 +/- 2 s (48%) (P less than 0.01) and the duration to 1 mm ST segment depression increased form 23 +/- 2 to 29 +/- 3 s (28%) (P less than 0.01). Systolic blood pressure fell from 118 +/- 3 to 111 +/- 4 mmHg but there was no change in intracoronary distal occlusion pressure. Thus during coronary occlusion isosorbide dinitrate prolongs the time to the onset of myocardial ischaemia.
Acute Disease↗
Laser assisted coronary angioplasty.
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Angioplasty, Balloon↗