Combination treatment with trimetazidine and diltiazem in stable angina pectoris

Objective—To assess antianginal efficacy and possible adverse haemodynamic effects of combination treatment with trimetazidine and diltiazem in patients with stable angina.
Design—Double blind, randomised, placebo controlled trial of four weeks duration.
Setting—Outpatient department of two Indian hospitals.
Subjects—64 male patients with stable angina, uncontrolled on diltiazem alone.
Interventions—Diltiazem 180 mg and trimetazidine 60 mg, or diltiazem 180 mg and placebo daily.
Main outcome measure—Change in exercise time to 1 mm ST segment depression.
Results—33 patients (55%) had no exercise induced angina at 3 mm ST segment depression at inclusion in the study (silent ischaemia). Intention to treat analysis showed that of 32 patients in each treatment group, the number (%) of patients responding to trimetazidine compared to placebo was: for anginal attacks, 28 (87.5) v 15 (46.9), p < 0.001; for exercise time to 1 mm ST segment depression, 21 (65.6) v 9 (28.1), p < 0.003; for exercise time to angina, 12 (37.5) v 5 (15.6), p < 0.05; and for maximum work at peak exercise, 17 (53.1) v 8 (25), p < 0.02. Compared to placebo, there was net improvement with trimetazidine in mean anginal attacks of 4.8/week (95% confidence interval (CI) 7.5 to 2.1; p < 0.002); in mean exercise times at 1 mm ST segment depression of 94.2 seconds (95% CI 182.8 to 5.6; p < 0.05), and at onset of angina of 113.1 seconds (95% CI 181.6 to 44.6; p < 0.02); and in mean maximum work at peak exercise of 1.4 metabolic equivalents (95% CI 2.4 to 0.3; p < 0.05).
Conclusions—Patients with stable angina uncontrolled with diltiazem had a clinically important improvement after combination treatment with trimetazidine, without adverse haemodynamic events or increased side effects.

Keywords: trimetazidine;  diltiazem;  blood pressure;  stable angina;  treatment     

Autonomic modulation of the atrial cycle length by the head up tilt test: non-invasive evaluation in patients with chronic atrial fibrillation

Objective—To determine the effects of upright posture compared with supine position on the dominant atrial cycle length (DACL) in patients with chronic atrial fibrillation.
Design—The power/frequency spectrum of QRST suppressed lead V1 ECG was studied in 14 patients in the supine position and during the head up tilt table test. The DACL changes were compared with changes in heart rate and blood pressure.
Results—Compared with the supine position, the upright position reduced the DACL from 160 to 150 ms (p < 0.01). The DACL was increased after returning to the supine position from the upright position, from 147 to 154 ms (p < 0.01). Heart rate increased from 91 beats/min in the supine position to 106 in the upright position (p < 0.01). There was a decrease in heart rate from 109 beats/min in the upright position to 93 after returning to the supine position (p < 0.01). No significant changes were seen in systolic or diastolic blood pressure. There were indications of an inverse relation between DACL and heart rate when comparing the supine position before and after tilt with the upright position (p < 0.001).
Conclusions—The sympathetic stimulation and vagal withdrawal induced by rising to upright body position are associated with a decrease in DACL during chronic atrial fibrillation. Thus a reflex increase in sympathetic discharge after induction of atrial fibrillation could favour the persistence of the arrhythmia.

Keywords: atrial fibrillation;  autonomic nervous system;  atrial cycle length;  heart rate     

Fibrinolytic potential is significantly increased by oestrogen treatment in postmenopausal women with mild dyslipidaemia

Objective—To study the effects of oestrogen replacement treatment on fibrinolytic potential in postmenopausal women.
Design—Randomised, double blind, placebo controlled trial of oral 17β-oestradiol.
Setting—Subjects were evaluated in the outpatient setting.
Patients—Nineteen postmenopausal women with mild dyslipidaemia, aged 44 to 69 years (mean (SD) 55.7 (6.7)).
Main outcome measures—Fibrinolytic activity (fibrin plate assay) and tissue plasminogen activator (t-PA) antigen were measured at baseline and after three, six, and nine weeks of each treatment.
Results—After nine weeks of 2 mg oestradiol treatment, there was a significant increase in fibrinolytic potential compared with placebo, as indicated by an increase in fibrinolytic activity (mean (SEM), 80 (9) v 54 (5) mm² of lysis in the fibrin plate, 2 mg v placebo, p = 0.002) and a decrease in t-PA antigen (5.8 (0.9) v 8.4 (1.2) ng/ml, 2 mg v placebo, p < 0.001). There was a similar trend with the 1 mg dose but the changes were less noticeable.
Conclusions—Hormone replacement treatment with 17β-oestradiol for nine weeks significantly increased fibrinolytic potential in postmenopausal women with mild dyslipidaemia. This suggests that the cardioprotective effect of oestrogen may be mediated, in part, by an increase in fibrinolytic potential.

Keywords: oestrogen;  fibrinolysis;  randomised controlled trial;  dyslipidaemia     

Cost effective management programme for heart failure reduces hospitalisation

Objective—To study the effects of a management programme on hospitalisation and health care costs one year after admission for heart failure.
Design—Prospective, randomised trial.
Setting—University hospital with a primary catchment area of 250 000 inhabitants.
Patients—190 patients (aged 65-84 years, 52.3% men) hospitalised because of heart failure.
Intervention—Two types of patient management were compared. The intervention group received education on heart failure and self management, with follow up at an easy access, nurse directed outpatient clinic for one year after discharge. The control group was managed according to routine clinical practice.
Main outcome measures—Time to readmission, days in hospital, and health care costs during one year.
Results—The one year survival rate was 71.8% (n = 79) in the control group and 70.0% (n = 56) in the intervention group (NS). The mean time to readmission was longer in the intervention group than in the control group (141 (87) v 106 (101); p < 0.05) and number of days in hospital tended to be fewer (4.2 (7.8) v 8.2 (14.3); p = 0.07). There was a trend towards a mean annual reduction in health care costs per patient of US$1300 (US$1 = SEK 7.76) in the intervention group compared with costs in the controls (US$3594 v 2294; p = 0.07).
Conclusions—A management programme for patients with heart failure discharged after hospitalisation reduces health care costs and the need for readmission.

Keywords: heart failure;  hospitalisation;  management;  health care costs;  nurse led clinics     

Investigation of the thoracic aorta in cholesterol embolism by transoesophageal echocardiography

Objectives—To examine the thoracic aorta of patients with severe cholesterol embolism (CE) by transoesophageal echocardiography (TOE).
Methods—The thoracic aorta of 20 consecutive patients with CE was compared with that in a control population matched for age and risk factors by TOE. Patients were prescribed steroids after CE was diagnosed. Follow up is reported and compared with results in the literature.
Results—Aortic plaques and debris were more common in patients with CE than in the control population (p < 0.001 and p < 0.0001, respectively). The mean (SD) number of aortic plaques in the CE patients was 2.6 (0.7). This aortic atheroma was found predominantly in the descending aorta. One patient died during a mean (SD) follow up of 24 (10) months.
Conclusions—Aortic atheroma, as detected by TOE, should be considered as the main source of CE. In addition, the prognosis in our series, in which steroids were systematically prescribed, is much better than in others reported in the literature.

Keywords: aortic atheroma;  transoesophageal echocardiography;  cholesterol embolism     

Nitrate induced coronary vasodilatation: differential effects of sublingual application by capsule or spray

Background—Sublingual nitroglycerin (glyceryltrinitrate, GTN) capsules or isosorbide dinitrate (ISDN) spray are routinely used to treat anginal attacks and to vasodilate maximally the epicardial coronary arteries during coronary angiography.
Objective—To compare the coronary vasodilatory effects of GTN capsules and ISDN spray with those induced by intracoronary GTN using quantitative coronary angiography.
Design—96 patients (79 men and 17 women; median age 59 years) were randomised to four groups to receive either a sublingual capsule containing 0.8 mg GTN or two puffs of spray delivering 0.8 mg ISDN, followed or preceded by an intracoronary bolus of 0.2 mg GTN used as reference for maximal vasodilatation.
Results—There was a significant increase in the mean diameter of coronary arteries in angiographically normal segments in patients who received either intracoronary GTN (groups 1 and 2) or ISDN spray (group 4) as a first application (group 1, 0.46 mm, +17%, (baseline vessel diameter 100%), p < 0.001; group 2, 0.45 mm, +13%, p < 0.001; group 4, 0.47 mm, +13%, p < 0.05). Patients who received a sublingual GTN capsule as the first application mode (group 3) had no significant change in epicardial vessel diameter (0.10 mm, +5%, p = 0.3).
Conclusions—Sublingual ISDN spray may be more efficacious than sublingual GTN capsules in certain patients with anginal attacks. ISDN spray should be preferred over capsules in coronary angiographic procedures.

Keywords: angiography;  isosorbide dinitrate;  nitroglycerin;  vasodilatation;  angina     

Heartstart Scotland: the use of paramedic skills in out of hospital resuscitation

Objective—To assess the frequency with which paramedic skills were used in out of hospital cardiac arrest and the effect of tracheal intubation on outcome.
Design—Retrospective analysis of ambulance service reports and hospital records.
Setting—Scottish Ambulance Service and hospitals admitting acute patients throughout Scotland.
Results—A total of 8651 out of hospital resuscitation attempts were recorded and tracheal intubation was attempted in 3427 (39.6%) arrests. One hundred and thirty six patients (3.7%) were intubated and 476 (9.1%) of the patients who were not intubated survived to hospital discharge (p < 0.001). Among the patients who were defibrillated the proportion intubated was highest in the patients who received the greatest number of shocks (p < 0.01). Among subjects receiving similar numbers of shocks survival rates were lower for intubated patients (p < 0.01). Patients with unwitnessed arrests were most frequently intubated and survival rates were lowest in this group.
Conclusions—Patients who are intubated seem to have lower survival rates. This may however reflect the difficulty of the resuscitation attempt rather than the effects of intubation. The use of basic life support skills rapidly after cardiac arrest is associated with the best survival rates.

Keywords: paramedics;  resuscitation;  myocardial infarction;  tracheal intubation;  prehospital care     

Does restrictive right ventricular physiology in the early postoperative period predict subsequent right ventricular restriction after repair of tetralogy of Fallot?

Objective—To assess the relation between immediate postoperative right ventricular (RV) diastolic physiology and subsequent diastolic function in patients after repair of tetralogy of Fallot.
Design—Serial prospective echocardiographic study early after surgical repair of tetralogy of Fallot and at mid-term follow up.
Setting—Tertiary referral centre.
Patients—34 patients who had repair of tetralogy of Fallot between 1992 and 1995 were studied.
Main outcome measures—Restrictive RV physiology defined as antegrade flow in the pulmonary artery in late diastole throughout the respiratory cycle.
Results—Sixteen of the 34 patients had early restrictive RV physiology. The need for transannular patch repair was an independent variable predictive of early restriction (odds ratio 4.3 (1.1-47), p < 0.05). Nine of 16 patients with early restriction also had restriction at follow up, while 15 of 16 patients without restrictive RV physiology continued without restriction. Early restriction was the only independent variable predictive of late restriction (odds ratio 6.0 (1.9-273), p = 0.01).
Conclusions—Early and mid-term restrictive RV physiology after repair of tetralogy of Fallot is related to the repair type. Although evidence for this physiology tends to resolve in the first few days after operation, it is highly predictive of subsequent abnormalities of RV diastolic function. Similarly, normal RV diastolic physiology without restriction in the immediate postoperative period persists in the mid-term and may be associated with the long term problems of progressive RV dilatation.

Keywords: restrictive right ventricular physiology;  evolution;  tetralogy of Fallot;  congenital heart disease     

Physiological cardiac reserve: development of a non-invasive method and first estimates in man

Objective—To investigate whether physiological cardiac reserve can be measured in man without invasive procedures and whether it is a major determinant of exercise capacity.
Design—Development of method of measurement and an observational study.
Setting—A regional cardiothoracic centre.
Subjects—70 subjects with a wide range of cardiac function, from heart failure patients to athletes.
Methods—Subjects underwent treadmill, symptom limited cardiopulmonary exercise tests to measure aerobic exercise capacity (represented by O₂max) and cardiac reserve. Cardiac output was measured non-invasively using the CO₂ rebreathing technique.
Results—Cardiac power output (CPO_max) at peak exercise was found to be significantly related to aerobic capacity: CPO_max (W) = 0.35 + 1.5O₂max (l/min), r = 0.87, p < 0.001. It also correlated well with exercise duration (r = 0.62, p < 0.001), suggesting that cardiac reserve is a major determinant of exercise capacity. In the study, cardiac reserve ranged from 0.27 to 5.65 W, indicating a 20-fold difference between the most impaired cardiac function and that of the fittest subject.
Conclusions—A non-invasive method of estimating physiological cardiac reserve was developed. The reserve was found to be a major determinant of exercise capacity in a population of normal subjects and patients with heart disease. This method may thus be used to provide a clearer definition of the extent of cardiac impairment in patients with heart failure.

Keywords: cardiac reserve;  cardiac power output;  oxygen consumption;  congestive heart failure     

Electrocardiographic changes after alcohol septal ablation in hypertrophic obstructive cardiomyopathy

Objective—To report acute and mid-term electrocardiographic changes in patients with hypertrophic obstructive cardiomyopathy (HOCM) after alcohol ablation of the first large septal branch of the left anterior descending coronary artery; and to relate electrocardiographic data with the left ventricular outflow tract pressure gradients.
Patients—Nine consecutive symptomatic patients with HOCM (mean (SD) age 45 (12) years).
Methods—Analysis of baseline and postprocedure ECGs and 24 hour ambulatory monitoring (up to six months). ECG data were related to left ventricular outflow tract pressure gradients.
Results—One patient developed complete atrioventricular block requiring permanent pacing. The PR interval was significantly prolonged up to third month after ablation. Immediately after the procedure all patients developed right bundle branch block. At the sixth month of follow up, right bundle branch block was present in four patients. New anterior ST elevation developed immediately after ablation in five of the nine patients, and new Q waves in four. The QRS duration was significantly prolonged immediately after ablation and during follow up. There was significant but transient prolongation of QT-mean and QTc-mean intervals. QT dispersion, QTc dispersion, and JTc-mean interval were not affected. JT and JTc dispersions were transiently prolonged. No serious ventricular arrhythmias were recorded during Holter monitoring, either before or after the procedure. There were no significant correlations between the left ventricular outflow tract pressure gradient and QTc, QT-d, QTc-d, JTc, JT-d, JTc-d, or QRS duration before and after ablation.
Conclusions—Alcohol septal ablation for HOCM induces significant changes in the resting ECG in most patients, despite the occlusion of a relatively small artery. The changes include new Q waves, new bundle branch block, transient anterior ST segment elevation, atrioventricular block, and transient prolongation of QT interval.

Keywords: hypertrophic obstructive cardiomyopathy;  alcohol septal ablation;  electrocardiography;  QT interval     

Residual and recurrent shunts after implantation of Cook detachable duct occlusion coils

Objective—To assess the presence and outcome of Doppler detectable shunts following implantation of the Cook detachable PDA coil.
Design—Prospective study.
Setting—Tertiary paediatric cardiac centre.
Patients—76 consecutive patients undergoing coil implantation (80 procedures).
Main outcome measures—Detection and colour Doppler echocardiographic appearance of residual or recurrent shunts, the timing of the appearance of recurrent shunts, and the time taken for spontaneous resolution of these shunts.
Results—Immediate occlusion was achieved in 52 patients. At one month 63 patients had complete occlusion and after three months the duct was completely occluded in 67 patients. In 27 cases small residual shunts were detected on echocardiography 10 minutes after the completion of the implantation procedure; 15 of these had resolved by 24 hours and 20 had resolved by three months. Recurrent shunts were detected after apparent initial complete occlusion in 11 cases 24 hours after coil implantation and in two cases one month after the procedure. Six recurrent shunts resolved on later follow up. Residual shunts appeared as single jets after implantation of a single coil, but up to three separate jets were detected after implantation of multiple coils.
Conclusions—Spontaneous resolution of small residual shunts occurs in most patients. The recurrence of small shunts after apparent complete occlusion suggests that recanalisation of the duct may occur in a small percentage of patients up to one month after occlusion. Residual shunts may take the form of multiple residual jets that may require implantation of further coils to achieve complete duct occlusion.

Keywords: coil occlusion;  arterial duct;  congenital heart disease     

Plasma concentrations of adrenomedullin correlate with the extent of pulmonary hypertension in patients with mitral stenosis

Objective—To examine the pathophysiological significance of adrenomedullin in the pulmonary circulation by investigating the relation between plasma concentrations of adrenomedullin and central haemodynamics in patients with mitral stenosis.
Methods—Plasma concentrations of adrenomedullin in blood samples obtained from the femoral vein, pulmonary artery, left atrium, and aorta were measured by a newly developed specific radioimmunoassay in 23 consecutive patients with mitral stenosis (16 females and seven males, aged 53 (10) years (mean (SD)) who were undergoing percutaneous mitral commissurotomy.
Results—Patients with mitral stenosis had higher concentrations of adrenomedullin than age matched normal controls (3.9 (0.3) v 2.5 (0.3) pmol/l, p < 0.001). There was a reduction in adrenomedullin concentrations between the pulmonary artery and the left atrium (3.8 (0.2) v 3.2 (0.4) pmol/l, p < 0.001). The venous concentrations of adrenomedullin correlated with mean pulmonary artery pressure (r = 0.65, p < 0.001), total pulmonary vascular resistance (r = 0.83, p < 0.0001), and pulmonary vascular resistance (r = 0.65, p < 0.001). Plasma concentrations of adrenomedullin did not change immediately after percutaneous mitral commissurotomy; however, they decreased significantly one week later.
Conclusions—Plasma concentrations of adrenomedullin are increased in patients with mitral stenosis. This may help to attenuate the increased pulmonary arterial resistance in secondary pulmonary hypertension due to mitral stenosis.

Keywords: adrenomedullin;  pulmonary hypertension;  mitral stenosis;  pulmonary circulation     

Non-cardiac, non-oesophageal chest pain: the relevance of psychological factors

Background—No cause has been determined for chest pain that is neither cardiac nor oesophageal in origin.
Aims—To compare the prevalence of lifetime psychiatric disorders and current psychological distress in three consecutive series of patients with chronic chest or abdominal pain.
Patients—Thirty nine patients with non-cardiac chest pain and no abnormality on oesophagogastroduodenoscopy, oesophageal manometry, and 24 hour pH monitoring; 22 patients with non-cardiac chest pain having endoscopic abnormality, oesophageal dysmotility, and/or pathological reflux; and 36 patients with biliary colic.
Methods—The Diagnostic Interview Schedule and the 28 item General Health Questionnaire were administered to all patients.
Results—Patients with non-cardiac chest pain and no upper gastrointestinal disease had a higher proportion of panic disorder (15%), obsessive-compulsive disorder (21%), and major depressive episodes (28%) than patients with gallstone disease (0%, p<0.02; 3%, p<0.02; and 8%, p<0.05, respectively). In contrast, there were no differences between patients with non-cardiac chest pain and upper gastrointestinal disease and patients with gallstone disease in any of the DSM-111 defined lifetime psychiatric diagnoses. Using the General Health Questionnaire, 49% of patients with non-cardiac chest pain without upper gastrointestinal disease scored above the cut off point (that is, more than 4), which was considered indicative of non-psychotic psychiatric disturbance, whereas only 14% of patients with gallstones did so (p<0.005). The proportions of such cases were however similar between patients with non-cardiac chest pain and upper gastrointestinal disease (27%) and patients with gallstones.
Conclusions—Psychological factors may play a role in the pathogenesis of chest pain that is neither cardiac nor oesophagogastric in origin.

Keywords: chest pain;  oesophageal manometry;  gastro-oesophageal reflux disease;  oesophageal pH monitoring;  psychiatric illness

     

Restenosis after elective coronary balloon angioplasty in patients with end stage renal disease: a case-control study using quantitative coronary angiography

Objective—To assess the rate of angiographic restenosis in patients with end stage renal disease after elective coronary angioplasty.
Design—A retrospective case-control study of 20 patients with end stage renal disease and 20 sex and age matched controls without renal disease, who had undergone primarily successful coronary angioplasty. Control coronary angiography was performed regardless of worsening or renewed incidence of anginal symptoms.
Main outcome measures—Group comparison of coronary morphology, as evaluated by quantitative coronary angiography, and of cardiovascular risk factors.
Results—The rate of angiographic restenosis was 60% in patients with renal disease and 35% in controls. In patients with end stage renal disease the following differences (mean (SD) were found versus controls: raised plasma fibrinogen (483 (101) v 326 (62) mg/dl, p < 0.001); raised plasma triglyceride (269 (163) v 207 (176) mg/dl, p < 0.01); smaller diameter of the coronary reference segment (2.59 (0.87) v 2.90 (0.55) mm, p < 0.10); smaller minimum luminal diameter of the dilated stenosis (0.77 (0.46) v 0.97 (0.27) mm, p < 0.05). Discriminant analysis showed that minimum luminal diameter before angioplasty (r = −0.79) and fibrinogen (r = +0.34) had the highest statistical association with restenosis.
Conclusions—The high rate of angiographic restenosis in patients with end stage renal disease seems to be related to the size of the vessel dilated and to an increased prothrombotic risk, as indicated by higher fibrinogen concentrations.

Keywords: renal disease;  coronary artery disease;  coronary angioplasty;  restenosis     

Long term results of reoperations for recurrent angina with internal mammary artery versus saphenous vein grafts

Objective—To evaluate the long term results of coronary reoperations for recurrent angina with internal mammary (thoracic) arteries versus vein grafts.
Design—Inception cohort of 103 patients with a mean follow up of 7.1 years (range 1.0-11.6).
Setting—Regional cardiothoracic centre.
Patients—Among 103 consecutive patients, mean (SD) age 61.8 (9.7) years, who were reoperated for recurrent angina between January 1982 and December 1991, 53 patients had unilateral or bilateral internal mammary artery (IMA) grafting supplemented or not with saphenous vein (SV) grafts (group A), and 50 patients underwent reoperative coronary surgery using SV grafts only (group B). The two groups were comparable in terms of demographic and clinicopathological data.
Measurements and results—Operative mortality was 5.6% (95% confidence interval 4.6 to 6.6) for group A, and 10% (8.2 to 11.8) for group B (p > 0.05). Probability of freedom from new recurrence of angina was 86% at 5 and 10 years in group A, compared with 56% and 25% respectively in group B (p = 0.005). Freedom from cardiac events was estimated to be 81% at 5 and 10 years in group A, v 52% and 20% for group B, respectively. Actuarial survival was 95% v 93% at 3 years, 95% v 85% at 5 years, and 88% v 71% at 10 years after reoperation (p > 0.05).
Conclusions—The long term results of IMA are superior to SV grafts in terms of freedom from new recurrence of angina and other cardiac events. The IMA is thus the conduit of choice in coronary revascularisation.

Keywords: coronary artery bypass;  coronary reoperation;  recurrent angina;  internal thoracic (mammary) artery     

A case-control investigation of the relation between hyperlipidaemia and calcific aortic valve stenosis

Objective—To investigate the relation of hyperlipidaemia to calcific aortic valve stenosis.
Design—A case-control study designed to detect a clinically relevant difference in the fasting plasma concentrations of total cholesterol between the groups at the 5% level with a power of 90%. Predefined subgroup analyses were based on presence of significant coronary disease and valve morphology (that is, bicuspid or tricuspid).
Setting—A district general hospital.
Subjects—20 patients with severe calcific aortic stenosis and 20 controls.
Results—Mean (SD) fasting plasma total cholesterol in patients with aortic stenosis was 0.79 (1.50) mmol/l greater than in the controls (p = 0.029). The magnitude of differences between patients with aortic stenosis and controls was similar whether the patients had coronary artery disease (0.78 (1.73) mmol/l) or not (0.80 (1.37) mmol/l). The presence of a stenosed tricuspid aortic valve was associated with a significant increase in plasma cholesterol (1.70 (0.87) mmol/l, p = 0.012). For bicuspid valves the degree of elevation of plasma cholesterol was less and not statistically significant.
Conclusions—Calcific aortic stenosis is associated with hypercholesterolaemia, especially when the valve is tricuspid. Further studies are necessary to confirm that the relation is causal. This finding may have implications for measures to prevent the most common cause of cardiac valve replacement in the developed world.

Keywords: calcific aortic stenosis;  hypercholesterolaemia;  hyperlipidaemia     

Self expandable stents for relief of venous baffle obstruction after the Mustard operation

Objective—Obstruction of the venous pathways after Mustard repair for transposition of the great arteries is associated with an increased risk of arrhythmia and sudden death. The purpose of this study was to assess the effectiveness of the largest (tracheal 22 × 40 mm) Wallstents in treating baffle obstructions.
Design—Retrospective analysis of patients with stented venous pathways.
Subjects—Eleven patients with baffle obstruction after Mustard repair for transposition of the great arteries.
Interventions—Stenoses were dilated with an 18 or 20 mm balloon. However, recoil was noticed in 11 patients: immediately (n = 7) or on repeat angiography (n = 4). Eighteen stents were implanted (mean (SD)) 18 (3.3) years postoperatively. After dilatation a tracheal Wallstent (11.5 F) was deployed.
Main outcome measures—Relief of obstruction, haemodynamic improvement.
Results—In the inferior vena cava, 10 stents were deployed in seven baffle obstructions with an increase in diameter from 9.8 (2.4) mm to 16.5 (1.4) mm (p < 0.01) and a mean (SD) pressure gradient decrease from 5.1 (3.6) mm Hg to 1.4 (2.0) mm Hg; in the superior vena cava, eight stents were implanted increasing the diameter from 9.1 (3.7) mm to 15.6 (3.8) mm (p < 0.001) with a decrease in mean pressure gradient from 5.1 (2.7) mm Hg to 1.9 (1.5) mm Hg. No complications were experienced during implantation. No anticoagulation was prescribed. During follow up (1.7 (0.6) years; range, 0.9-2.6) no problems were noted; five patients were re-catheterised without change in measurements. There was no evidence of peal formation in any of the stents.
Conclusion—It is concluded that Wallstents are safe, easy to use, and effective in relieving baffle obstruction. Anticoagulation does not seem neccessary.

Keywords: Mustard procedure;  venous baffle obstruction;  stent     

S-Nitrosoglutathione inhibits platelet activation and deposition in coronary artery saphenous vein grafts in vitro and in vivo

Objective—To investigate platelet activation and deposition in human saphenous vein and internal mammary artery grafts following coronary artery bypass in vitro and in vivo, as well as inhibition of activation by the platelet selective nitric oxide donor S-nitrosoglutathione (GSNO).
Design—Controlled in vitro and in vivo studies.
Setting—Tertiary cardiac centre.
Patients—24 patients undergoing coronary artery bypass surgery requiring vein and artery grafts.
Interventions—In vitro: human platelet rich plasma was perfused through segments of vein and artery, with or without GSNO 10^-6 M, and the platelet count was measured in the effluent. In vivo: indium-111 labelled antibody against the platelet α granule protein GMP-140 was injected at the end of coronary bypass grafting and γ counts were compared between vein and artery grafts with or without systemic infusion of GSNO (40 nmol/min).
Results—In vitro: platelet count in perfused vein (< 70% of baseline) decreased more than in artery segments (89-94% of baseline) (p < 0.001). The platelet count was unchanged with GSNO in vein and artery segments. In vivo: γ counts were greater at all time points over vein than artery grafts (p < 0.05), and were reduced by infusion of GSNO (p < 0.05).
Conclusions—Platelet activation is greater in vein than in artery grafts in vitro and in vivo. Activation, which contributes to early vein graft failure, was inhibited by GSNO.

Keywords: coronary artery bypass surgery;  platelet activation;  S-nitrosoglutathione;  ischaemic heart disease     

Endoluminal vessel reconstruction by stent placement in patients with obstructive coronary artery disease who are poor surgical candidates

Objective—To investigate the safety and efficacy of endoluminal vessel reconstruction by intracoronary stenting in patients with single or multivessel disease who have been turned down for surgical revascularisation.
Design—An observational, single centre trial of consecutive patients being followed up clinically.
Setting—Tertiary referral centre.
Patients—43 patients treated between 1995 and 1996 with a clinical follow up period of at least six months.
Main outcome measures—Acute procedural success following intervention (defined as a residual stenosis of < 30% with normal antegrade flow and without acute clinical complications); major adverse clinical events (death, myocardial infarction, repeat intervention, clinical restenosis); and functional status during follow up.
Results—Acute procedural success was achieved in 39 patients. Failures resulted from a refractory no reflow phenomenon with Q wave myocardial infarction (two patients), and from subacute stent thrombosis (one patient) and saphenous vein graft rupture at stent site (one patient), both manifesting by non-Q wave myocardial infarction. During a follow up period of 17 (8) months (mean (SD)), three of these patients died. Clinical restenosis was treated by repeat percutaneous intervention in 11 patients, while 28 patients remained asymptomatic. On a Kaplan-Meier estimate, the proportion of patients without adverse clinical events at two years was 65%.
Conclusions—Percutaneous reconstruction of diseased coronary arteries in patients with single or multivessel disease turned down for surgical revascularisation may be considered as a valuable treatment option. On follow up, more events seem to be encountered than after elective de novo stenting of discrete coronary lesions. This is probably related to higher clinical restenosis rates.

Keywords: coronary artery disease;  stents;  restenosis     

Distribution of fast heart rate episodes during paroxysmal atrial fibrillation

Objective—To investigate the defibrillator waiting time (time between the recognition of atrial fibrillation and the actual shock) by studying paroxysmal atrial fibrillation episodes with RR intervals shorter than a certain limit (that is, episodes during which defibrillation should not be attempted).
Methods—Long term 24 hour Holter recordings from a digoxin v placebo crossover study in patients with paroxysmal atrial fibrillation were analysed. In all, 23 recordings with atrial fibrillation episodes of at least 1000 ventricular cycles and with < 20% Holter artefacts or noise were used (11 recorded on placebo and 12 on digoxin). For each recording, the mean ("mean waiting time") and maximum ("maximum waiting time") duration of continuous sections of atrial fibrillation episodes with all RR intervals shorter than a certain threshold were evaluated, ranging the threshold from 400 to 1000 ms in 10 ms steps. For each threshold, the mean and maximum waiting times were compared between recordings on placebo and on digoxin.
Results—Both the mean and maximum waiting times increased exponentially with increasing threshold. Practically acceptable mean waiting times less than one minute were observed with thresholds below 600 ms. There were no significant differences in mean waiting times and maximum waiting times between recordings on placebo and digoxin, and only a trend towards shorter waiting times on digoxin.
Conclusions—Introduction of a minimum RR interval threshold required to deliver atrial defibrillation leads to practically acceptable delays between atrial fibrillation recognition and the actual shock. These delays are not prolonged by digoxin treatment.

Keywords: atrial defibrillator;  shock delivery;  ventricular proarrhythmia;  digoxin