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Biomedical subjects

D L Clement

Publications and source records attributed to D L Clement.

At least 127 records · Page 7Linked to original sources

Alternating capture of the ventricle and an unusual pacing rate.

The recent improvements in technology of cardiac pacing are often responsible for difficult electrocardiograms at follow-up (Gladstone et al., 1987). Therefore, it seems an advantage that most modern pacemakers include diagnostic software functions to explain the pacing behaviour (event markers, intracardiac electrograms...). In this case report an electrocardiogram, showing pacing dysfunction of a physiologic pacemaker with rate response is presented. It was possible to understand what was happening without electrograms, but confirmation of our interpretation of the pacing behaviour was only possible with telemetric data.

Aged↗

Home versus office monitoring of blood pressure: a European multicentre study of high blood pressure.

A prospective multicentre study has been set up to examine the following primary questions: (1) Is there a better correlation between blood pressure and mortality, morbidity or organ damage when blood pressure is measured by ambulatory recordings rather than by the usual office method? (2) Is there a difference in the rates of mortality, morbidity and organ damage when treatment is guided by ambulatory values instead of by office values? The aim is to study 2000 patients with primary hypertension, aged 35-70 years, for 5 years. Ambulatory recordings will be made every 6 months. Treatment will be based at random on either office or ambulatory blood pressure readings at each centre.

Adult↗

Relapsing digital ulcers.

A 72-years-old male patient is described who presented with relapsing, digital ulcers on both feet, accompanied by digital cyanosis ("purple toes"). All episodes occurred 5 months after starting coumarin treatment for chronic atrial fibrillation and low output failure. Massive mural thrombosis was discovered of the entire abdominal aorta. Because of the clinical picture, together with progressive renal failure and persistent eosinophilia, cholesterol embolization from an ulcerated atherosclerotic plaque within the mural thrombus was highly suspected. Besides the clinical presentation of our patient, the spectrum of cholesterol embolization is much wider. The role of coumarin therapy is still speculative. Numerous reports however, indicate a potential role in precipitating the syndrome. The only therapy available consists of removing the source whenever possible.

Aged↗

Measurement of autoimmune response against collagen types I, III, and IV by enzyme-linked immunosorbent assay, and its application in infective endocarditis.

In these enzyme-linked immunosorbent assays for determination of autoantibodies (IgG, IgM) against collagen type I (ACA I), III (ACA III), and IV (ACA IV), we use commercially available antigen preparations. Inhibition curves showed limited cross-reactivity between these different collagen preparations, the major interference being observed after addition of collagen type III in the ACA I procedures. Imprecision (CVs) for high- and low-titer samples ranged between 1.5% and 7.9% (within-run) and 5.5% and 12.7% (between-run) for ACA I, between 2.2-8.7% and 4.5-10.7% for ACA III, and between 1.3-5.9% and 7.4-11.6% for ACA IV. Significantly increased humoral immune response against collagen types I and III (P less than 0.001) could be demonstrated during the first month of infective endocarditis. In contrast, only borderline increases, however constant, of autoimmune response against basement-membrane collagen (ACA IV) were noticed during 90 days of follow-up.

Adult↗

Incidence and prognostic significance of asymptomatic ischaemia in patients with sustained ventricular arrhythmias.

The role of ischaemia in the natural history of sustained monomorphic ventricular tachycardia not related to acute myocardial infarction is not well documented. We examined 38 patients (mean age 60 years, mean ejection fraction 33%) with programmed electric stimulation and thallium scintigraphy to study the presence of perfusion defects and to assess its prognostic significance. Reversible perfusion defects (RPD), alone or in combination, were seen in 17 patients (44.7%), persistent perfusion defects (PPD) in 31 (81.5%), and RPD and PRD combined existed in 14 patients (37%). Normal scintigrams were obtained in only four patients. Segmental analysis gave a mean 'infarction score' (number of PPDs on a total of 15 segments) of 4.2; the mean 'ischaemia' score (number of RPDs) was 1.2. Recurrence of tachycardia or sudden death was observed in 14 patients during a follow-up of 17 +/- 13 months. The predictive value (PV) of the presence of a RPD for recurrence was 63%, the PV of its absence was 82%; the predictive accuracy was 74% (P = 0.0069). This was as important as the data obtained with the drug studies (+PV 83%; -PV 86%; overall PV 83%, P = 0.002). The mean ischaemia score was 3.3 in the group with recurrence and 2 in the patients without recurrence. As pharmacological studies are only feasible in a subgroup with inducible tachycardia, thallium scintigraphy is of benefit to a larger group for predicting effective drug therapy and the risk of recurrence.

Adult↗

QT-related rate-responsive pacing during acute myocardial infarction.

UNLABELLED: We studied the findings in a patient who had a TX 915 pacemaker and who was suffering from an acute inferior myocardial infarction. On admission, we observed pacing at the upper rate limit due to excessive adrenergic tone. Shortly thereafter a strong vagal reaction occurred, and the pacing rate fell back to the lower rate limit. This condition was improved with atropine. CONCLUSIONS: (1) In the described condition the TX pacemaker behaved in a very "physiological" fashion; (2) Sudden strong cholinergic activity lengthened the QT interval; (3) Programming of a steep slope must be avoided in coronary artery disease; (4) Stimulus-T-wave intervals at maximal adrenergic and cholinergic stimulation should be taken into account when programming the slope and the T-wave sensing window.

Aged↗

Late coronary spasm complicating successful angioplasty of the left main coronary artery.

A patient with successful percutaneous transluminal coronary angioplasty of the left main coronary artery is described. Two days later coronary angiography was performed because of recurrence of angina pectoris. Spontaneous spasm at the angioplasty site was documented. This potentially lethal complication issues a severe warning against angioplasty of the left main trunk.

Angiography↗

2:1 atrial capture as the cause of pacemaker alternans.

Two patients with sinus node disease and a physiologic pacemaker presented with 2:1 atrial capture. Both atrial leads were screw-in leads (6957 J, Medtronic), with normal position on X-rays. When atrial capture was absent, paced QRS complexes resulted in retrograde conduction to the atria. The next atrial spike was followed by a P wave and normal AV conduction. With atrial screw-in leads, alternating atrial capture may be caused by an altered ventricular and atrial contraction pattern, when retrograde conduction exists. Its presence may precede permanent exit block by several weeks.

Aged↗

Physiologic pacing in the elderly. Effects on exercise capacity and exercise-induced arrhythmias.

It is not clear whether hemodynamic and other benefits from dual-chamber pacing also exist in elderly patients. We studied a group of 18 elderly patients (mean age 74 +/- 4 yrs) with exercise testing in DDD and VVI modes in a randomized way to compare the effects of these pacing modes on exercise capacity, atrial rate and exercise-induced arrhythmias. Patients were selected when complete heart block was present without clinical evidence of sinus node dysfunction. Significant differences were observed: atrial rate was lower during exercise in DDD-mode (p less than 0.01); exercise time and cumulative load increased (p less than 0.05); maximal oxygen uptake was improved (p less than 0.05). Some of these differences were less clear in a subgroup with replacement of a VVI-device by DDD-stimulation. No differences could be observed in severity of exercise-induced arrhythmias. No evidence of sinus node dysfunction was found during exercise. Reprogramming of atrial sensitivity was required in 3 patients, with reprogramming to DVI because of paroxysmal atrial fibrillation once. Two patients died within a mean follow-up period of 13 months. Sinus rhythm was present at the most recent evaluation in all patients, including the patient stimulated in the DVI mode. Physiologic stimulation is of value for elderly patients with an active life style and complete heart block. Reprogramming to another pacing mode is only seldom necessary.

Aged↗

Primary cardiac tumors: retrospective evaluation of 15 consecutive patients.

During a decade (1975-1985) 15 patients have been treated for a primary cardiac tumor at the University Hospital of Ghent. Histological examination revealed both benign (n = 12) (myxoma, pseudomyxoma, myxoid degeneration) and malignant (n = 3) (angiosarcoma) tumors. Tumor diagnosis generally was made by echocardiographic and/or angiocardiographic examination of patients presenting with various constitutional and/or cardiac symptoms. In two patients however diagnosis became obvious by histological examination of the material removed during acute embolectomy. All tumors were surgically resected with the aid of extracorporeal circulation. Benign tumors have generally good prognoses, although rhythm or conduction disturbances, complete obstruction or embolization can entertain malignant consequences. Three of our patients died of such a complication. Therefore all cardiac tumors should be resected as soon as possible after diagnosis. One patient showed evidence of recurrence of the tumor. Malignant heart tumors have bad prognoses: all three of our patients died within two years.

Adult↗

A six years review on 53 cases of infective endocarditis: clinical, microbiological and therapeutical features.

Microbiological features, diagnostic investigations, treatment, and complication rate in 53 cases of infective endocarditis were reviewed in this study. Infection occurred both on prosthetic (47%) and native valves (38%), while in 15% of the cases no prior valvular disease was known. Streptococcal (38%) and staphylococcal (30%) infections were predominant. In 17% of the cases apparent negative blood cultures were obtained. The most frequent portal of entry was dental infection or manipulation (45%), however in 28% of the patients etiology remained obscure. Major clinical signs and symptoms included heart murmurs (96%), fever (91%), dyspnoea (32%), and splenomegaly (30%). Echocardiography revealed vegetations in 78%, aortic and mitral valve being nearly equally affected. All patients were medically treated and 53% received antibiotics prior to blood cultures. Associations of ampicillin or penicillin with an aminoglycoside (43%) and penicillinase-resistant antibiotics (30%) were most frequently administered. In 28% of the patients, it was necessary to insert a prosthetic (aortic or mitral) valve. During follow-up, heart failure (28%), embolization (11%), and infections (11%) were the major complications.

Adult↗

Cardiac output-changes during hemodialysis with ultrafiltration.

Cardiovascular hemodynamics were studied noninvasively before, during and after hemodialysis with ultrafiltration in 18 patients on chronic hemodialysis. The cardiac output (CO) was determined by a continuous wave Doppler method. Overall, no major CO changes were seen (7.8 +/- 0.6 l/min post- versus 7.4 +/- 0.5 l/min pre-dialysis). Mean blood pressure rose slightly but significantly from 103 +/- 4 mmHg before to 113 +/- 3 mmHg after hemodialysis (p less than 0.01). Important interindividual differences in the intradialytic evolution of CO were observed. In patients with previous myocardial infarction or dilated cardiomyopathy (n = 12), CO rose significantly from 7.3 +/- 0.7 l/min before to 8.4 +/- 0.6 l/min after hemodialysis (p less than 0.05), while in patients without manifest myocardial disease (n = 6) CO decreased from 7.5 +/- 0.7 l/min to 6.6 +/- 0.9 l/min (NS). Comparison of the evolution of CO in both groups by variance analysis revealed a significant difference (p less than 0.01). It is concluded that, in response to hemodialysis with ultrafiltration, CO probably will increase in patients with myocardial infarction or congestive cardiomyopathy, but probably will decrease in patients without.

Adult↗

Lack of effect of cicletanine on plasma digoxin levels.

Six patients stabilized on long-term once daily oral digoxin were entered into a study to monitor the effect of adding a single dose of oral cicletanine (50 or 100 mg) on plasma digoxin levels. The study was performed over 2 days, a control day and a second involving the addition of the test drug to the patient's medication. No significant change in plasma digoxin concentration was found and the combined treatment was well tolerated in terms of clinical and laboratory parameters.

Adult↗

Definition of arterial hypertension according to age and sex.

Although the historical debate between Pickering and Platt has never been settled, most scientists have felt that hypertension should not be defined as a disease state, qualitatively different from normotension with a sharp dividing line in between them. Still, in clinical practice, there is a need for well defined limits which one should initiate therapeutic actions that should not be taken below such a limit. In fact, in trying to escape to setting up a sharp limit, clinicians have tried to find a level above which benefits of decreasing blood pressure could outweigh the potential harm caused by the therapeutic interventions. However even in that way, finding such a limit is a most difficult enterprise; it has necessitated many large trials which certainly have not resolved yet all our questions. First, one should realize that blood pressure by itself is not a constant value; following blood pressure over a certain period shows its large variations from "normotensive" ranges to clearly "hypertensive" levels in the same individual. As soon as one is spoiled by this type of information, it becomes hardly conceivable to define someone's blood pressure without ambulatory recordings of some kind. This is also valid for finding the above mentioned limit of therapeutic benefit; an European International multicenter studied is being set up in this respect (HOME BP). Moreover, whatever the definition of blood pressure, its relationship to mortality, morbidity and organ damage, also, is not a constant one.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗

Peripheral vascular responses during carotid baroreceptor stimulation in normotensive and hypertensive subjects.

1. The carotid baroreceptors were stimulated for 2 min by neck suction at -30 and -60 mmHg in 19 normotensive subjects and 12 patients with moderate essential hypertension. 2. Blood pressure was measured with a mercury sphygmomanometer and heart rate was derived from beat-to-beat analysis of the electrocardiogram. Blood flow was measured simultaneously at calf and finger with venous occlusion plethysmography and the vascular resistance was calculated. 3. During neck suction at -30 and -60 mmHg there was a significant decrease in arterial blood pressure and heart rate. There was a transient vasodilatation of the calf blood vessels, while there was a sustained vasoconstriction of the finger blood vessels. These results were qualitatively similar in both groups; however, there were quantitative differences. 4. These experiments show that there is a selective autonomic control of the different peripheral vascular beds by the carotid baroreceptors in both normotension and mild essential hypertension.

Adult↗

Unpredictable cause of early recurrence of angina pectoris after successful double coronary angioplasty.

Early recurrence of symptoms after successful coronary angioplasty is usually due to restenosis of the angioplasty site. Multilesion progression of atherosclerosis in the presence of patent prior dilated segments has not, to our knowledge, been reported as a cause of early recurrent angina after successful double coronary angioplasty. As both new lesions were also successfully dilated, this case demonstrates that multivessel coronary angioplasty is a repeatedly effective and patient-friendly procedure to treat symptomatic coronary atherosclerosis with rapid and unpredictable rate of progression.

Angina Pectoris↗