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Biomedical subjects

M de Belder

Publications and source records attributed to M de Belder.

10 recordsLinked to original sources

Percutaneous coronary intervention: recommendations for good practice and training.

Cardiologists undertaking percutaneous coronary intervention (PCI) are excited by the combination of patient and physician satisfaction and technological advance occurring on the background of the necessary manual dexterity. Progress and applicability of percutaneous techniques since their inception in 1977 have been remarkable; a sound evidence base coupled with the enthusiasm and ingenuity of the medical device industry has resulted in a sea change in the treatment of coronary heart disease (CHD), which continues to evolve at breakneck speed. This is the third set of guidelines produced by the British Cardiovascular Intervention Society and the British Cardiac Society. Following the last set of guidelines published in 2000, we have seen PCI activity in the UK increase from 33,652 to 62,780 (87% in four years) such that the PCI to coronary artery bypass grafting ratio has increased to 2.5:1. The impact of drug eluting stents has been profound, and the Department of Health is investigating the feasibility of primary PCI for acute myocardial infarction. Nevertheless, the changes in the structure of National Health Service funding are likely to focus our attention on cost effective treatments and will require physician engagement and sensitive handling if we are to continue the rapid and appropriate growth in our chosen field. It is important with this burgeoning development now occurring on a broad front (in both regional centres and district general hospitals) that we maintain our vigilance on audit and outcome measures so that standards are maintained for both operators and institutions alike. This set of guidelines includes new sections on training, informed consent, and a core evidence base, which we hope you will find useful and informative.

Angioplasty, Balloon, Coronary↗

Silent myocardial ischaemia in patients with proved coronary artery disease: a comparison of diabetic and non-diabetic patients.

OBJECTIVE: To determine whether diabetic patients with coronary artery disease are more likely to experience silent myocardial ischaemia than subjects without diabetes. SUBJECTS: Patients undergoing coronary angiography at a regional cardiothoracic unit, identified as having diabetes from the local district diabetic register/database. DESIGN: The coronary angiograms and exercise treadmill tests of 100 diabetic and 100 non-diabetic patients who all had significant coronary artery disease and maximal effort exercise tests were reviewed. Patients were individually matched for age group, gender, severity of coronary artery disease, and indication for treadmill test. OUTCOME MEASURES: Significant coronary artery disease was defined as a stenosis of greater than 50% diameter in at least one of the major coronary artery segments. Exercise tests were graded as positive if the electrocardiographic (ECG) recording showed planar or downsloping ST segment depression of > or = 1 mm in more than two leads at 80 ms post J-point or if there was a blood pressure fall > or = 10 mm Hg after an initial rise. A negative exercise test was defined as one in which the subject experienced no pain, had no ECG changes after maximal effort and had a normal blood pressure response. Subjects who did not experience any form of typical angina-type pain during a positive exercise test were defined as having an episode of silent ischaemia. Patients with symptomatic ischaemia were those who experienced typical angina-type pain with accompanying ST segment changes. Patients with a negative exercise test were defined as having "undetermined ischaemia". This category included all those without ECG evidence of myocardial ischaemia during the exercise test (with or without accompanying chest pain). RESULTS: In the diabetic patients, 34% had ECG evidence of silent ischaemia on treadmill testing compared with only 19% of the non-diabetic controls (p < 0.02). CONCLUSIONS: This study shows that diabetic patients with proved coronary artery disease have a higher risk of developing silent myocardial ischaemia during exercise than non-diabetic patients.

Adult↗

Patient empowerment in secondary prevention of coronary heart disease.

Despite a large evidence base, the practice of secondary prevention in coronary artery disease is suboptimum and needs improvement. We have shown that although patient empowerment led to an increase in cholesterol checks, the action taken by health-care professionals as a result of these checks was poor.

Anticholesteremic Agents↗

Primary ventricular fibrillation is associated with increased paced right ventricular electrogram fractionation.

BACKGROUND: The mechanisms of spontaneous ventricular fibrillation (primary VF) in patients without structural heart disease are obscure. A new technique has shown that in patients with hypertrophic cardiomyopathy conduction of fractionated ventricular paced beats, recorded at several right ventricular sites, is prolonged in individuals who have suffered a VF arrest, and this may reveal one component of a reentrant substrate. Patients with primary VF were studied with the same methods to determine whether similar abnormalities are present in this group. METHODS AND RESULTS: Nine patients with primary VF were studied by pacing one right ventricular (RV) site by use of a constant drive train with an extrastimulus inserted every third beat and reducing the extrastimulus coupling interval (S1S2 interval) by 1 ms on each occasion while recording at three other sites. The delay of each fractionated potential in the high-pass-filtered electrograms in response to the extrastimulus was determined and used to form conduction curves of delay versus the S1S2 interval. These curves were repeated by pacing each RV site in turn and recording from the other three sites. The curves were characterized by determining the S1S2 interval at which electrogram components increased in delay by 0.75 ms/20 ms reduction in S1S2 interval and the increase in electrogram duration between a coupling interval of 350 ms and 1 ms above refractoriness. Seven control patients were studied using the same method. The mean increase in electrogram duration in VF patients was 13 ms (range, 3 to 23 ms) compared with 4 ms (range, -2 to 14 ms) in unaffected control patients. The extrastimulus coupling interval at which delay increased was 318 ms (range, 293 to 334 ms) in VF patients and 274 ms (range, 265 to 284 ms) in control patients (P < .01). There was no difference between the number of fractionated potentials in VF patients and control patients. CONCLUSIONS: In primary VF patients, the individual potentials within fractionated electrograms have increased delays when compared with control patients. This may identify one component of a reentrant arrhythmic substrate.

Adolescent↗

Rupture of a sinus of Valsalva aneurysm through the tricuspid septal leaflet.

We report a case of rupture of an aneurysm of the noncoronary sinus of Valsalva with the tract of the fistula emerging through the tricuspid septal leaflet. This rare pathology created a diagnostic dilemma, as the direction of the jet of blood was alternating between the right atrium and the right ventricle.

Adult↗

Identification of a high risk subgroup of patients with silent ischaemia after myocardial infarction: a group for early therapeutic revascularisation?

Asymptomatic ("silent") ischaemia has been shown to be of prognostic significance in patients with stable and unstable angina and more recently in patients recovering after myocardial infarction. No therapeutic regimen has yet been shown to improve the prognosis of patients with silent ischaemia after infarction, which can be found in as many as a third of these patients. Attempts to achieve therapeutic revascularisation in all these patients may be undesirable, but early revascularisation could be especially beneficial in some selected high risk patients. Two hundred and fifty consecutive clinically stable survivors of myocardial infarction who had predischarge submaximal exercise tests were followed up for a year. Silent ischaemia was found in 27% of these patients; 15% had symptomatic ischaemia. Patients with a positive exercise test were prescribed a beta blocker before discharge. Mortality in patients with silent (9.4%) and symptomatic (5.4%) ischaemia in the first year after infarction was not significantly different. Patients with symptomatic ischaemia were more likely to have undergone coronary artery bypass grafting in the first year. Patients with silent ischaemia were, however, significantly more likely to die than patients with a negative exercise test (relative odds 12:1). Patients with silent ischaemia and an abnormal blood pressure response or who could not complete a submaximal exercise protocol were at particularly high risk, being 32 times more likely to die than those with a negative test (95% confidence interval from 3.3 to 307 times more likely). First year mortality in this group was 22%. The benefits of therapeutic revascularisation in this high risk group need to be studied.

Coronary Angiography↗

Patterns of coronary artery disease in post-infarction ventricular septal rupture.

Cardiac angiography was reviewed in 91 patients with post-infarction ventricular septal rupture. The results were compared with those of 123 stable survivors who had a positive submaximal exercise test early after infarction. Anterior infarction and occlusion of the infarct vessel were more common in those with ventricular septal rupture than in the comparison group. In the group with ventricular septal rupture there was more left ventricular damage, with aneurysm formation in two thirds, and coronary angiography showed more single than triple vessel disease. In the comparison group there was more triple vessel disease than single vessel disease. Angiographically demonstrable collaterals to the infarct territory were not seen or only very faintly seen in 82% of those with septal rupture. Well developed collaterals were seen in two thirds of the comparison group. These patterns of coronary disease suggest that ventricular septal rupture is more likely in patients with coronary occlusion and little or no collateral support to the infarct territory.

Collateral Circulation↗