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Biomedical subjects

X Marchand

Publications and source records attributed to X Marchand.

At least 19 recordsLinked to original sources
PubMed1992

Predictive value of the P wave at implantation for atrial fibrillation after VVI pacemaker implantation.

This study assesses the value of P wave measurements on the surface ECG at implantation, in the prediction of atrial fibrillation in VVI paced patients. From a consecutive series of 320 pacemaker implantations 172 VVI paced patients for symptomatic atrioventricular block (AVB) (n = 126; mean age 69 +/- 14) or sick sinus syndrome (SSS) (n = 56; mean age 68.6 +/- 12) and in sinus rhythm at implantation were used in this study. P wave duration in V1 is correlated with the incidence of atrial fibrillation during 5 years of follow-up. V1 at implantation was significantly longer (114.6 +/- 2.7 msec) in the patients who developed atrial fibrillation than in those who did not (91.9 +/- 2.7 msec) (P < 0.001). Although positive predictive accuracy increases progressively for higher V1 values for AVB and SSS, the negative predictive and diagnostic accuracy of V1 criteria were less in SSS. Application of the Bayes' theorem showed that in SSS the probability to develop atrial fibrillation is 33% for V1 < 110 msec and is for V1 < 90 msec still higher than that reported in DDD paced patients. In the AVB group the probability to develop atrial fibrillation is 8% for V1 < 110 msec and 6% for V1 < 100 msec. It seems, therefore, that atrial stimulation (AAI or DDD) is always indicated in SSS. In AVB with V1 < 100 msec, DDD pacing, if not needed for other indications, apparently does not offer much benefit in the prophylaxis of atrial fibrillation.

Aged↗
PubMed1992

[P wave changes and atrial fibrillation after implantation of VVI type pacemaker].

The P waves of patients with VVI pacemakers were compared with those of DDD pacemakers at implantation and then regularly for 5 years. A certain number of cardiac pathologies are known to cause P wave changes. The incidence of atrial fibrillation (AF) was much higher in VVI than in DDD patients. In the VVI group, the incidence was much greater in patients paced for sinus node disease than in patients paced for AVB. Analysis of sinus P wave characteristics in 320 patients with VVI pacemakers shows progressive abnormalities of atrial function with time. The expression of this atrial dysfunction is a statistically significant prolongation of the P wave in V1 and dII and of the terminal part of the P wave in V1. The factors responsible for this abnormality and which favours the occurrence of AF are quasi-permanent pacing, the presence of retrograde conduction and an abnormality of atrial activation at the time of implantation.

Aged↗
PubMed1990

Kinetics and hemodynamic effects of intravenous nicardipine modified by previous propranolol oral treatment.

Intravenous nicardipine, 5 mg, was administered in two comparable groups of eight patients with chronic coronary artery disease but no clinical signs of heart failure. One group had received no previous treatment and served as a control group, and the other had received long-term treatment with large oral doses of propranolol. Blood concentrations of nicardipine were higher, and the area under the plasma concentration curve was greater in the group previously treated by propranolol. The total clearance of nicardipine was decreased in patients taking propranolol, without a change in the half-life of the drug. Typical hemodynamic responses, namely, a decrease in aortic pressure and in arterial resistances, were greater and more lasting in patients previously treated orally by propranolol. Filling pressure remained stable in both groups. The nicardipine infusion did not induce signs of dromotropic or inotropic negative effects in either group. The greater and more lasting hemodynamic effects of nicardipine in the group previously treated orally by propranolol do not seem to be related to an overall hemodynamic action of propranolol, but are probably due to higher nicardipine plasma levels, and may be caused by a decrease in hepatic blood flow induced by propranolol, with a consequent decrease in nicardipine clearance and by a smaller nicardipine volume of distribution in the propranolol group.

Administration, Oral↗
PubMed1990

Evolution of P wave characteristics after pacemaker implantation.

This study is an investigation of the long-term effects of VVI pacing on the atrium as derived from the evolution of P wave characteristics of 285 patients. The occurrence of left and right atrial disease is demonstrated as well as the evolution of left atrial hypertrophy in some cases. A comparison is made with DDD pacing and special attention is given to the progression to atrial fibrillation.

Aged↗
PubMed1990

[Influence of preload changes on the filling function of the left heart ventricle studied by Doppler echocardiography].

Left ventricular filling may be studied non-invasively by Doppler echocardiographic recording of transmitral blood flow. This study reports the variations in this flow induced by changing cardiac preload by administering trinitrin or by vascular filling in 27 patients undergoing catheterisation. Left ventricular end diastolic pressure (LVEDP) was measured by the pig-tail catheter used for ventriculography. Transmitral flow was recorded by pulsed Doppler using the apical view. The parameters studied were those of the early diastolic E wave and the end diastolic A wave. The hemodynamic and echocardiographic measurements were performed under basal conditions, after trinitrin and after vascular filling. Trinitrin was given to 14 patients and led to a fall in LVEDP from 17.6 +/- 4.5 to 6.7 +/- 1.4 mmHg (p less than 0.001). The amplitude of the mitral E wave decreased and the E/A ratio fell from 0.93 +/- 0.37 to 0.71 +/- 0.32 (p less than 0.001). Thirteen patients underwent vascular filling which increased LVEDP from 10.9 +/- 5 to 27 +/- 4 mmHg (p less than 0.001). The mitral E wave increased and the E/A ratio rose from 0.96 +/- 0.32 to 1.27 +/- 0.23 (p less than 0.01). The patients received trinitrin and then underwent vascular filling. The LVEDP decreased from 16 +/- 3.9 to 8 +/- 2.9 mmHg (p less than 0.001) and then rose to 28.3 +/- 3.5 mmHg (p less than 0.001). The E/A ratio fell after trinitrin from 0.91 +/- 0.40 to 0.58 +/- 0.30 (p less than 0.01) and then rose to 1.42 +/- 0.60 (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Obstructive calcification of the thoracic aorta revealed by dilated cardiomyopathy.

Obstructive calcification of the thoracic aorta appears as acquired coarctation of the aorta. The case we present is of note because it presented as a dilated cardiomyopathy. The diagnosis, suspected on chest X-ray, was confirmed by catheterization, aortic angiography and thoracic computer tomography. The patient underwent aortic endarterectomy, but died in the post-operative period. Review of the literature shows that the pathogenesis of the condition remains unclear.

Aorta, Thoracic↗
PubMed1988

[Bepridil and bundle of His block. Apropos of a case].

The first case of atrioventricular block located in His bundle observed during oral treatment with bepridil is reported; the block subsided when the drug was discontinued and reappeared when it was reintroduced. Electrophysiological studies performed with bepridil have shown that, as could be foreseen from its beneficial or undesirable effects, this calcium antagonist has some properties of Vaughan Williams' class I antiarrhythmic agents and alters subnodal conduction. Clinical studies indicate that in therapeutic doses this alteration has little or no significance, but it may reach clinical expression when latent of patient pre-existing disorders of conduction within or below His bundle are present.

Bepridil↗
PubMed1987

[Prevalence of late potentials in ventricular tachycardias. Comparison with a control group].

High amplification electrocardiographic recording of ventricular late potentials was introduced a few years ago and seems to be a simple, reliable and reproducible method to identify patients at a high risk of sudden death and ventricular tachycardia, principally during the chronic phase of myocardial infarction. However, few authors have studied quantitatively the prevalence of late potentials in patients with ventricular tachycardia compared with a sufficiently large sample of healthy subjects. In this study 34 patients with sustained ventricular tachycardia (11 women, 23 men, mean age 58 years) and 131 healthy subjects (29 women, 102 men, mean age 29 years) underwent high amplification time-averaged ECG recording, and an algorithmic analysis of the tracings was conducted, using the Simson method. Three numeric parameters were used in the interpretation of the tracings: HFRMSA = mean RMS amplitude of the last 40 milliseconds of QRS; HFD40 = delay in signal decrease from amplitude 40 mu v to baseline, and delta QRS = difference in QRS duration with 0-250 Hz and 25-250 Hz filterings. Normal values, as determined from measurements in healthy subjects, were: HFRMSA above 27 mu v, HFD40 below 35 ms and delta QRS below 13 ms. Late potentials were present when at least one of these criteria was positive. When these norms were applied to patients with sustained ventricular tachycardia the prevalence of late potentials was 76%, rising to 90.4% in the subgroup of 21 patients with coronary disease. With the method thus defined the specificity for each criterion taken separately is 97.5%. According to the norms, only one control subject (0.8%) gave a false-positive result.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

[Rhythm disorders].

Explore the source record for details and available documents.

Anti-Arrhythmia Agents↗
PubMed1987

[The risk of cerebrovascular complications in the combination of pregnancy and mitral valve prolapse].

A case of left intraventricular thrombus, developed from a myxoid mitral valve and revealed by embolic cerebral vascular accidents at the end of a pregnancy, is reported. The links between a mitral valve prolapse and cerebral vascular accidents of embolic origin are studied during pre- and post-partum periods, where coagulation alterations are reviewed. It appears that, in pregnant women with a mitral valve prolapse, there is a maximum risk of developing an intra-cardiac thrombus in the last four weeks of pregnancy or immediately after delivery; this justifies, during that time, a thorough sonocardiographic monitoring.

Adult↗
PubMed1987

[Malignant pheochromocytomas. Apropos of a case with multiple metastatic localizations].

We are reporting a case of malignant pheochromocytoma surgically treated initially for an isolated left pararenal localization, and which recurred several years later accompanied with numerous metastases. Despite of a treatment with Iodine 131 MIBG, the evolution was rapidly fatal with a picture of cardiac failure. This cardiac involvement would be linked to a myocarditis directly secondary to the catecholamines and causing a marked increase of the free fatty acids concentration in the heart tissue. In reference to this case, all the data which may tend to suspect the malignant nature of a pheochromocytoma, present in 10 p. cent of the cases, are successively reviewed. There is no clinical specificity. The presence of a mixed secretion with marked urinary dopamine secretion, would not present, for all authors, the same criteria of specificity. Thoraco-abdominal scan and scintigraphy with iodine 131 MIBG are the two tests permitting to demonstrate, with a great sensitivity and specificity, an extra-adrenal localization, which is the best argument in favor of a malignancy since 30 to 40 p. cent of extra-adrenal pheochromocytomas are malignant, more especially as the metastases are located in areas where there are no embryonic remnants of tissues containing chromaffin cells. This permits to appreciate the difference between a non-malignant multicentric pheochromocytoma and a malignant pheochromocytoma. The ideal treatment of a malignant pheochromocytoma rests on surgery under the condition that there are ony one or two metastases. This procedure is preceded by a sodium nitroprusside preparation and followed with an alpha-blockers treatment. In case of multiple metastases, the therapeutic use of iodine 131 MIBG seems to be a tempting alternative.

Adrenal Gland Neoplasms↗