Carotid artery disease: when and how to treat?
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Arteriosclerosis↗
Biomedical subjects
D L Clement
Publications and source records attributed to D L Clement.
Ambulatory blood pressure recordings: a new dimension in arterial hypertension.
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Ambulatory Care↗
[Intracardial shock for the conversion of chronic atrial fibrillation].
Internal cardioversion was attempted in three patients with chronic atrial fibrillation, refractory to conventional external direct current shocks. Endocardiac shocks were delivered between the proximal electrode on a multipolar USCI pacing catheter and a back paddle. This is positioned with the tip proximal of the bundle of His, and the proximal ring electrode floating in the right atrium. Two patients were converted with 200 Joules, one needed 400 Joules. Two of our three patients were chronically maintained in sinus rhythm after the initial conversion, one had recurrence within 24 hours.
Aged↗
Peripheral action of spironolactone: plethysmographic studies.
The relation between vasodilation and the blood pressure-reducing action of spironolactone was studied in a randomized, placebo-controlled, double-blind, crossover study using 9 patients with essential hypertension. Vasodilation was studied by measuring blood flow in finger and calf (representative of skin and muscle circulation) by an electrocardiographic-triggered venous-occlusion plethysmograph. Treatment with spironolactone (100 mg twice daily for 4 weeks) produced significant decreases in systolic and diastolic blood pressure without significantly affecting heart rate. Blood flow through finger and calf increased, sometimes markedly, in 6 of the 9 patients, while vascular resistance decreased. This study confirms that the antihypertensive action of spironolactone is associated with vasodilation in many patients.
Blood Flow Velocity↗
Hemodynamic and renal effects of atrial natriuretic peptide in congestive heart failure.
The hemodynamic and renal effects of anaritide (human atrial natriuretic peptide 102-126), a synthetic analog of atrial natriuretic peptide, were evaluated in 35 patients with chronic New York Heart Association class II to IV heart failure. There were 32 men and 3 women, aged 33 to 75 (mean +/- standard error of the mean 56 +/- 2) years. In the first phase of the study, right-sided heart catheterization was performed, and anaritide was administered as 1-hour infusions. The rate of the infusion varied among patients from 0.03 to 0.3 micrograms/kg/min. In response to anaritide, there were decreases in mean systemic arterial (94 +/- 2 to 87 +/- 2 mm Hg), right atrial (10 +/- 1 to 8 +/- 1 mm Hg), mean pulmonary arterial (33 +/- 2 to 28 +/- 2 mm Hg) and pulmonary artery wedge (22 +/- 2 to 15 +/- 2 mm Hg) pressures (all p less than 0.05). Cardiac index increased (2.39 +/- 0.15 to 2.62 +/- 0.15 liters/min/m2, p less than 0.05) and heart rate was unchanged. Systemic vascular resistance decreased significantly, but pulmonary vascular resistance was unchanged. There were increases in urine volume (1.6 +/- 0.2 to 2.3 +/- 0.4 ml/min), sodium excretion (47 +/- 13 to 74 +/- 20 muEq/min) and fractional excretion of sodium (0.41 +/- 0.11 to 0.59 +/- 0.14%, all p less than 0.05), while potassium excretion and creatinine clearance did not change. In the second phase of the study, patients received 2-hour infusions of anaritide (0.03 to 0.6 micrograms/kg/min) and placebo with noninvasive monitoring.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Catecholamine levels and pacing behavior of QT-driven pacemakers during exercise.
It is thought that increasing catecholamine levels in the heart are partly responsible for shortening of the repolarization time and so indirectly for the pacing behavior of the QT driven pacemaker. Adrenaline and noradrenaline (NA) plasma levels were determined at rest, during symptom-limited exercise, and during recovery more than 1 month after the implantation of a 919 or a Rhythmyx pacemaker (Vitatron, The Netherlands) in eight patients (age 54-85 yrs). Significant increases were detected in NA level (from 0.57 +/- 0.23 ng/mL to 2.15 +/- 0.76 ng/mL), but not in the circulating adrenaline level. The correlation coefficient of the mean pacing rate and the mean NA level during exercise and recovery was 0.963 (P less than 0.0001), the correlation coefficient with the mean oxygen consumption was 0.888 (P less than 0.01). No correlation with the adrenaline level was observed. The correlation coefficient of the changes of pacing rate and the changes of NA level during exercise and recovery was 0.882 (P less than 0.005). The pacing rate of the new generation of QT driven pacemakers is closely correlated with the noradrenaline spillover in the plasma, not with the adrenaline level. A short delay (less than 1 minute) is observed in the adaptation.
Aged↗
Combination of flecainide and mexiletine for the treatment of ventricular tachyarrhythmias.
A combination of oral flecainide and mexiletine was given to 11 patients in whom monotherapy with one of these drugs was ineffective for the suppression of inducible ventricular tachycardia or fibrillation. In eight of 11 studies, combination therapy prevented inducibility of a sustained ventricular tachycardia or resulted in induction of only nonsustained tachycardia (P = 0.0003, when compared to monotherapy). In one patient, a slow ventricular tachycardia was induced. During exercise testing ventricular tachycardia occurred in two of these nine patients, and ventricular fibrillation in another patient. Seven patients received combination on the long term, for a mean of 18 months. One patient had recurrences of ventricular tachycardia which was well tolerated. Another patient had a recurrent episode of ventricular fibrillation, but was successfully resuscitated. Severe congestive heart failure occurred in two patients. ACE inhibitors were given to them and to another four patients. No other important unwanted effects occurred. The combination of mexiletine and flecainide is very effective in suppressing inducible sustained ventricular tachycardia. The efficacy of this combination to prevent recurrences of ventricular tachyarrhythmias is acceptable. Exercise testing is of importance to unmask proarrhythmic effects before discharge from hospital.
Aged↗
Differential effects of vasodilators on forearm and calf vessels.
Because the literature comparing the effects of vasodilators on forearm and calf vessels is very scarce, the authors compared different vasodilators used in cardiovascular medicine in a group of volunteers. The peripheral effects were measured in the sitting position by plethysmography at the calf and at the forearm. At the forearm, comparable dilator effects were seen in arteries and veins. At the calf there was a trend for arterial flow to decrease as venous capacitance increased. Vascular response seen in one limb was not representative of the whole circulation. The changes observed were dependent not only on the vascular area investigated but also on the dose used.
Adult↗
Office versus ambulatory recordings of blood pressure (OvA): a European multicenter study. The Steering Committee.
The long-term prognostic value of ambulatory blood pressure recordings in essential hypertension is poorly documented. A European Multicenter study has been set up to evaluate office versus ambulatory (OvA) recordings during a follow-up period of 5 years in a minimum of 2000 patients. The end-point of the study is the question of whether ambulatory blood pressure measurements are better correlated with patient morbidity and mortality than office recordings. In a specific substudy, short-term evolution (6 months) of left ventricular hypertrophy will be followed in untreated hypertensives with randomly allocated treatment. A number of readaptations of the primary protocol are discussed.
Blood Pressure Determination↗
A comparison of sotalol and procainamide in symptomatic ventricular tachycardia.
UNLABELLED: The effects of oral sotalol were compared with 1000 and 1500 mg of procainamide in 23 patients with sustained ventricular tachycardia. The predictive value of an induction study after procainamide was assessed. The mean age of the study group was 62 +/- 12 years, and the mean ejection fraction was 32 +/- 16%. The cycle length (CL) of the induced tachycardia, the coupling interval (CI) of the first extrastimulus (in ms), and the number of noninducible (NI) patients are given in the table below. (table; see text) One patient developed torsades during the loading period of sotalol and is included in the number requiring cardioversion (DC). Important proarrhythmic effects (spontaneous occurrence of tachycardia) were seen twice after procainamide. Induction suppression by procainamide predicted success with sotalol (p = 0.0013). CONCLUSION: Ventricular tachycardia seems to be less often inducible after oral sotalol than after procainamide. The success of procainamide during programmed electrical stimulation predicts the same for sotalol. If ventricular tachycardia remains inducible after oral sotalol, it is faster than after procainamide but slower than the baseline tachycardia. Both drugs slightly prolong refractoriness.
Aged↗
International study of ketanserin in Raynaud's phenomenon.
PURPOSE: The effects of ketanserin on primary or secondary Raynaud's phenomenon due to connective tissue disease were studied in a large, international group of patients. PATIENTS AND METHODS: The study population consisted of 222 patients from 10 countries. After a run-in period of one month of placebo therapy, patients were randomly assigned in a double-blind manner to receive ketanserin 40 mg three times daily (n = 113) or placebo (n = 109) for three months. Total finger blood flow was measured in 41 patients in a warm and cool room before and during treatment. Vasospastic episodes were assessed by diaries and global evaluations. RESULTS: A significant reduction of 34% in frequency of episodes occurred with ketanserin, compared to 18% with placebo (p = 0.011). There was a 1% reduction in duration of episodes with ketanserin therapy, compared to a 2% increase with placebo therapy, but this finding was not statistically significant (p = 0.29). No difference was observed in severity of attacks. Global evaluations by investigators (p = 0.03) and patients (p less than 0.01) showed an overall benefit with ketanserin compared to that seen with placebo. Patients with primary or secondary Raynaud's phenomenon responded similarly to treatment. No changes in total finger blood flow were found. CONCLUSION: Ketanserin significantly improves the subjective symptoms of patients with primary or secondary Raynaud's phenomenon and is an appropriate agent to use in this disease when conservative measures fail.
Blood Pressure↗
Incidence of arrhythmias after atrial or dual-chamber pacemaker implantation.
The incidence of sustained atrial, pacemaker-mediated and ventricular rhythm disturbances was studied retrospectively in a consecutive series of 112 patients without a history of preexisting atrial tachyarrhythmias, receiving an atrial or dual-chamber pacemaker. Early atrial fibrillation (during the first week) was recorded twice. Late atrial fibrillation was seen in seven patients, flutter in one, yielding a total incidence of 8.9% for 22 months. There were no significant differences with respect to age, aetiology, electrocardiographic diagnosis, pacing history, or the measured intracardiac P wave between the group with and the group without atrial fibrillation. Treatment with digoxin reverted three patients to sinus rhythm, association of digoxin and amiodarone, six patients. One patient with congestive heart failure remained in atrial fibrillation. Pacemaker-mediated tachycardia was not a major problem. One patient of a subgroup with known ventricular arrhythmia had a non-sustained ventricular tachycardia during programming at follow-up; sustained ventricular tachycardia was not recorded. Reprogramming to VDD, DVI or VVI was done in 6/100 patients. The incidence of atrial fibrillation or flutter in highly selected patients with dual-chamber or atrial pacing is moderately low. It is not possible to identify patients with a high risk for development of atrial fibrillation; when it occurs, it is easily controlled with drugs. DDD pacing seems to be safe in patients with a history of serious ventricular arrhythmias, treated with appropriate drugs.
Aged↗
Low-dose oral sotalol for monomorphic ventricular tachycardia: effects during programmed electrical stimulation and follow-up.
The effects of oral sotalol were compared with the findings obtained in the baseline study of a group of 26 consecutive patients with sustained monomorphic ventricular tachycardia or ventricular fibrillation and inducible ventricular tachycardia. The mean age was 62 years and the mean ejection fraction 33%. The number of non-inducible patients after sotalol administration (mean dose of 251 +/- 81 mg day-1) was 13 out of 21 (62%). The cycle length of the induced tachycardia changed from 293 +/- 32 to 303 +/- 41 ms (non-significant (NS]. The coupling interval of the first extrastimulus did not lengthen for the subgroup with persistent inducibility. The number of patients requiring defibrillation during the induction study did not decrease on (2/8) or off drugs (6/22). After the first administration of oral sotalol, two patients developed polymorphic ventricular tachycardia or torsade de pointes and one suffered from left ventricular failure. Long-term treatment with sotalol was given to 15 non-inducible patients, and two inducible patients, combined with an AICD or a pacemaker. Over a mean follow-up period of 13 months, three recurrences were observed in these 17 patients, including the patient with the AICD. This represents an efficacy of 82% for patients chronically treated with a low dose of oral sotalol.
Administration, Oral↗
Circulatory changes in muscle and skin arteries in orthostatic hypotension and constitutional hypotension.
It is not known whether there are vascular changes in the peripheral circulation of patients with orthostatic hypotension and patients with constitutional hypotension. Therefore, blood flow was studied simultaneously at the calf (mainly muscle circulation) and at the finger (mainly finger circulation) with ECG-triggered venous occlusion plethysmography. Calf and finger blood flow were measured for 20 min at rest and during reactive hyperaemia due to an arterial occlusion for 3 min. Vascular resistance was calculated from the blood flow and arterial blood pressure. In orthostatic hypotension there is a decreased vasodilator capacity of the calf resistance vessels and not of the finger resistance vessels. In constitutional hypotension there is a decreased vasodilator capacity of the calf and finger resistance vessels. These results suggest that there are structural or functional changes, or both, in the muscle and skin circulation of patients with constitutional hypotension, whereas there are only structural or functional changes, or both, in the muscle circulation of patients with orthostatic hypotension.
Adult↗
Calcium antagonists in the treatment of essential hypertension: review of international studies.
The purpose of the present article is to review a number of studies dealing with the efficacy of calcium antagonists, in particular verapamil, in the treatment of essential hypertension. Several well-controlled studies have shown that verapamil causes a significant decrease in both systolic and diastolic pressure. Blood pressure decrease, which is of the same magnitude as with propranolol, is related to pretreatment values and, according to some authors, to age, but the latter statement is being refuted by others. Using a slow-release preparation, it can be shown that the 24-h blood pressure profile with once-daily administration is quite similar to the profile seen with three-times-daily administration of the regular formulation of verapamil. It has also been documented that the blood pressure decrease persists during 1-year continued administration. Optimal effect is seen at 240-320 mg/day. The most frequent side effects are constipation, flushing, and conduction disturbances. It is often proposed that the addition of a diuretic to verapamil does not increase the antihypertensive effect, but recent studies provide evidence to the contrary. Finally, ambulatory pressure recordings have shown that nifedipine does not decrease blood pressure variability. In general, calcium antagonists seem to be effective antihypertensive drugs but their place in the daily antihypertensive treatment has still to be defined.
Calcium Channel Blockers↗
Behavior of a respiratory driven pacemaker and direct respiratory measurements.
In 10 patients with a mean age of 76 +/- 8 years, a rate responsive pacemaker (Meta-MV, Telectronics) was implanted in the left pectoral site. An exercise test was performed in SSI ("adaptive") mode, allowing the device to measure the changes in thoracic impedance. The "slope number" at maximal exercise was chosen to program the pacemaker for a second exercise test in rate responsive mode. Direct measurements of respiratory rate and minute volume were correlated with the pacing rate. After 1 minute of exercise, pacing rate increased by 6% and it decreased smoothly after maximal exercise. The programmed maximal rate was reached at the maximum exercise level in six patients. During 24-hour Holter recording, the mean maximal pacing rate was 103 +/- 18 beats/min. For individual patients, a good correlation of pacing rate with respiratory rate (r = 0.757), oxygen consumption (r = 0.731), and minute volume (r = 0.800) was observed. The data from the entire group showed a highly significant correlation of changes in pacing rate and in respiratory parameters for different levels of exercise and recovery. In a subgroup of five patients, the slope numbers at maximal exercise were reproducible after 10 months. It was concluded that minute volume and its changes were recognized in a reliable way by the Meta-MV pacemaker.
Aged↗
Anti-myosin humoral immune response following cardiac injury.
A sensitive and highly specific ELISA assay was developed to determine the anti-myosin humoral immune response (AMA) in various heart diseases: acute viral myocarditis, infective endocarditis, acute myocardial infarction, and valve and coronary bypass surgery. The mean study entry AMA titer of each patient group was already significantly increased compared with age matched controls. During further follow-up (90 d) all the groups except for endocarditis showed a significant increase of AMA titer compared with their entry titer. Anti-myosin antibody titer were higher after cardiac surgery than after myocardial infarction or inflammatory heart disease. These results suggest that anti-myosin immune response is not limited to infectious processes in which the pathogen induces antibodies which cross-react with heart constituents but is merely caused by direct cardiac injury. Myosin as a major compound of heart cellular proteins turned out to be a good candidate to trigger immune response after cardiac injury.
Adolescent↗
[Studies on the mechanism of blood pressure variability].
Blood pressure variability has been known in the cardiovascular clinic for a long time. The mechanisms of the variations are largely unknown; it was the aim of the present work to approach this question. In a first group of studies, the role of the adrenergic receptors was examined. The results have shown that the adrenergic system does not play an important role in this phenomenon as administration of beta and of alpha blocking agents is unable to diminish the amplitude of the blood pressure variations; this was confirmed by other studies showing no correlation between blood pressure variability and the response to sympathetic function tests. However, there was a positive correlation with the level of blood pressure. In a second part, the role of the cholinergic system was investigated; atropine was found to diminish, both in dogs as in men, the amplitude of blood pressure variability. No decrease of blood pressure variability was seen with calcium antagonists. Thus, blood pressure variability is depending on the level of blood pressure and cholinergic activity; since these mechanisms only explain part of blood pressure variability, further research will be needed to unravel this challenging question.
Adrenergic alpha-Antagonists↗