Biomedical subjects

P Gosse

Publications and source records attributed to P Gosse.

At least 73 records · Page 4Linked to original sources

PubMed1996

[Assessment of arterial distensibility by ambulatory monitoring of QKD interval. Reproducibility of the method].

We have proposed the use of the ambulatory monitoring of the timing of Korotkoff sounds (QKD interval) to assess arterial distensibility. This interval is inversely linked to pulse wave velocity. The study of its variations according to spontaneous blood pressure changes during 24 h allows to calculate indices of arterial distensibility independent of actual blood pressure. A normalized QKD100-60 is calculated as the value for a 60 batt/min heart rate and a 100 mmHg systolic blood pressure from the individual multivariate linear relationship between these 3 variables. This interval decrease with arterial distensibility. We tested the reproducibility of this method in 28 normal subjects (14 males, 14 females, aged 43 +/- 16 years) who underwent two 24 h recordings during daily routine separated by one week. Standard deviation of differences for QKD100-60 was 12 ms, the coefficient of variation 6% and the coefficient of repeatibility 24 ms. So QKD100-60 shows a good reproducibility in the same range that 24 h blood pressure means.

Adult↗

PubMed1995

Elevated nocturnal blood pressure assessed by ambulatory automatic monitoring during a stay at high altitude.

The aim of this study was to explore, in healthy children, the arterial blood pressure response to a 3-week stay at high altitude (4200 m). An auscultatory automatic ambulatory pressuremeter was used to avoid undue environmental influence on the measurement. The blood pressure was monitored three times in a group of ten boys, aged 10.5 (CI 0.9 years): at sea level (control values), at an altitude of 2100 m after at least 24 h of acclimatization and after at least 24 h at 4200 m altitude. Each period of monitoring extended over 24 h with 10-min intervals between successive measurements. Arterial blood pressure was evaluated separately for the night and day periods. Nocturnal recordings revealed an increase with altitude in systolic as well as in the diastolic blood pressure. Because of the technique used to gather data, this is thought to have represented an independent effect of altitude without interference from the medical environment or diurnal activity.

Acclimatization↗

PubMed1995

Coronary reserve in experimental myocardial hypertrophy.

Three types of dysfunction of the coronary circulation have been described in experimental models of hypertension associated with left ventricular hypertrophy: (1) reduced coronary reserve, (2) a relative decrease in perfusion of subendocardial layers, (3) a shift to the right, i.e. to higher pressures, of the circulation pressure autoregulation range. These abnormalities are also observed in hypertensive patients, although it is significant that they do not appear to be related to the extent of left ventricular hypertrophy. The exact causes of these abnormalities have yet to be elucidated. Left ventricular hypertrophy does not seem to be an essential factor, although in certain experimental models of hypertension, there does appear to be a mismatch between the development of the coronary vasculature and hypertrophy of the myocytes. The stresses in vessels due to the increase in systolic, and especially intraventricular diastolic pressure can be viewed as additional aggravating factors. The essential abnormalities are structural and/or functional alterations in arterial walls. The structural alterations are reflected by a narrowed lumen due to parietal thickening. This may result from growth of muscle fibres (hypertrophy or hyperplasia) or collagen tissue and/or remodelling of tissues with no overall change in mass. Functionally, the reduced ability of the arteries to stretch, resulting from endothelial alterations may also play a role in the abnormalities observed in hypertensive patients. In our studies, we examined the effect of the antihypertensive drug perindopril on the coronary circulation in renovascular hypertensive rat (two kidneys--1 clip). We found that this inhibitor of angiotensin converting enzyme (ACE) led to a regression of left ventricular hypertrophy with a return to normal of the coronary reserve. Other studies using either this model or the spontaneously hypertensive rate has also pointed to a beneficial action of ACE inhibitors and other antihypertensive agents on the coronary circulation with reversal of the structural alterations in arterioles. Coronary disease is the main cause of mortality in hypertensive patients. Ironically, antihypertensive therapy has yet to live up to its promise of reducing significantly either the incidence or severity of coronary disease in such patients. Specific alterations of the coronary circulation may account for the relative failure of antihypertensive drugs, despite their proven efficacy in other systems (e.g., stroke prevention). The coronary circulation is unique in certain important respects. It is tightly regulated, maintaining an almost constant flow rate over a wide range of aortic arterial pressures (40-160 mmHg). Extraction of oxygen by the myocardium is almost maximal under resting conditions, and so the circulatory reserve depends almost entirely on the capacity to increase blood flow. This reserve is quite large since there may be a 4 to 5-fold increase in coronary flow rate in response to effort. Another significant detail is that myocardial contraction may lead to an interruption of coronary flow, especially in the deep subendocardial layers, which thus tend to be perfused solely during diastole. This last factor can be seen as the Achilles heel of the coronary circulation, which may be severely limited by myocardial hypertrophy, especially in patients with hypertension.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1995

[Detection of left ventricular hypertrophy in arterial hypertension].

Left ventricular hypertrophy is an important risk factor in hypertension and the results of the HYCAR study confirm that it is possible to treat this risk factor independently of an action on the blood pressure. Should systematic echocardiography be performed in every hypertensive patient to diagnose left ventricular hypertrophy and follow up its outcome with treatment? This attitude seems to be premature for two reasons. Firstly, echocardiography, though much more sensitive than electrocardiography for diagnosing left ventricular hypertrophy, has a number of limitations. Good recordings cannot be obtained in all patients; even under the best conditions of reproducibility, the measurement of left ventricular mass is not excellent and does not allow reliable individual follow-up of treatment; even the criteria of left ventricular hypertrophy used at present are open to criticism. Secondly, it remains to be shown whether the reversibility of left ventricular hypertrophy, independently of lowering the blood pressure, improves the prognosis of the hypertensive patient. The intensive research into this problem, further stimulated by the encouraging results of the HYCAR study, should help define the role and value of echocardiography in the future management of hypertension.

Echocardiography↗

PubMed1995

[Evaluation of trandolapril alone or in combination with a calcium channel blocker in hypertensive patients over 60 years of age].

The efficacy and safety of trandolapril alone and in combination with a calcium channel blocker were evaluated in 13,147 hypertensive patients over 60 years old. Two patient groups were constituted. After a 2-week wash-out period, the patients in group I received monotherapy with trandolapril 2 mg/day for 4 weeks. Trandolapril was continued for another 4 weeks in responding patient, otherwise the dosage of trandolapril was doubled or another antihypertensive was added. Group 2, composed of patients previously treated with a calcium channel blocker with insufficient efficacy, was treated according to the same treatment regimen, but the calcium channel blocker was maintained throughout the study. 13,147 patients (group 1: 11,329 patients, group 2: 1,818 patients) with a mean age of 68 +/- 7 years were followed. After 4 weeks of treatment, the blood pressure measured by mercury sphygmomanometer decreased from 176 + 11/99 +/- 8 mmHg to 164 +/- 12/87 +/- 7 mmHg (p < 0.0001). This blood pressure fall was similar in group 1 (-22 +/- 12/-12 +/- 8 mmHg) and in group 2 (-21 +/- 11/-12 +/- 8 mmHg). In the pure systolic HT subgroup treated by trandolapril monotherapy, the antihypertensive effect predominantly affected the SBP (-23 +/- 12/- 4 +/- 6 mmHg). The antihypertensive effect was correlated with the initial blood pressure. In group 1, in the case of insufficient response to trandolapril monotherapy, the addition of a calcium channel blocker was the strategy which achieved the most marked antihypertensive effect (ANOVA, p < 0.0001). This bitherapy was more effective than the trandolapril+diuretic combination (-18 +/- 11/- 11 +/- 8 mmHg and -15 +/- 10/- 9 +/- 7 mmHg, respectively (p < 0.001). A total of 1,270 adverse events were reported by 996 patients (7.6%), leading to discontinuation of treatment in 372 patients (2.8%). The most frequent adverse effects were cough (2.8%), headache (0.8%), vertigo (0.8%) and nausea (0.5%). Only one minor equivalent of angioneurotic oedema was reported. In conclusion, trandolapril is effective and well tolerated in elderly hypertensive patients. In the case of pure systolic HTA, its action is essentially exerted on SBP. The combination of trandolapril+calcium channel blocker appears to be the most effective strategy in the case of incomplete blood pressure control by trandolapril alone.

Age Factors↗

PubMed1994

[Antihypertensive efficacy and tolerability of diltiazem and enalapril, alone or in combination. DESG. Diltiazem Enalapril Study Group].

OBJECTIVES: Since conversion enzyme inhibitors and calcium inhibitors may have synergic actions, we evaluated the antihypertensive effect and tolerance of prolonged-release diltiazem (300 mg/d) and enalapril (20 mg/d). METHODS: A double blind study included 176 patients with mild to moderate hypertension. Diltiazem was given to 89 (44 males, 45 females, mean age 49.91 +/- 10.50 years, mean resting diastolic arterial pressure 103 +/- 5 mmHg) and 87 (49 males, 38 females, mean age 51.37 +/- 12.13 years, mean resting diastolic arterial pressure 103 +/- 5 mmHg) received enalapril. Single drug therapy was given for 6 weeks and then continued for another 8 weeks in responders. At the end of the first 6-week period non-responders were given a combination regimen (diltiazem 300 mg and enalapril 20 mg). RESULTS: After 6 weeks of single drug therapy, 48 patients in the diltiazem group (61.5%) and 53 in the enalapril group (65.4%) had normal blood pressures which remained normal at the end of the trial 8 weeks later in 36 (76%) and 42 (82%) respectively. After 8 weeks of combined regimen 15 of the 24 non-responders (68%) to single drug diltiazem therapy had normal blood pressures as did 18 of the 23 non-responders (78%) to enalapril alone. Tolerance evaluated clinically, biologically and electrocardiographically was comparable to reports in the literature. CONCLUSION: Delayed prolonged-release diltiazem 300 mg and enalapril 20 mg thus had equivalent antihypertensive effects and were equally well tolerated. Combination therapy increased effectiveness without inducing any additional side effects.

Adult↗

PubMed1994

Assessment of arterial distensibility by monitoring the timing of Korotkoff sounds.

The timing of Korotkoff sounds, blood pressure, and heart rate can now be monitored in the ambulatory patient: the QKD interval is the time between the onset of the depolarization on the electrocardiogram (Q) and detection of the last Korotkoff sound (K) at the level of brachial artery during cuff deflation, corresponding to diastolic blood pressure (D). Because this interval is inversely related to pulse wave velocity, this recently developed device enables evaluation of the influence of blood pressure on arterial rigidity, providing valuable information on the properties of the arteries. In this study, we examined the influence of hypertension and age on the above parameters and their correlations to left ventricular mass. QKD interval, blood pressure, and heart rate were monitored over a period of 24 h (four measurements/hour) in 33 normotensive and 70 untreated essential hypertensive patients. The slopes of the plots of QKD interval versus systolic and pulse pressure during the 24 h were calculated for each patient. The influence of age and hypertension on these slopes was tested by comparison of matched groups and multivariate analysis. Moreover the relationships between these parameters and echocardiographically assessed left ventricular mass were studied in 37 patients. We found a reduction in mean QKD interval with age and hypertension, reflecting the recognized higher pulse wave velocity in these patients. The slopes of the plots of QKD interval versus blood pressure were also lower in these patients, indicating the smaller influence of a change in blood pressure on pulse wave velocity in patients with stiffer arteries.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

Correlation of signal-averaged P wave with electrophysiological testing for atrial vulnerability in strokes of unexplained etiology.

UNLABELLED: Atrial fibrillation is considered the main cause of cardioembolic strokes. After detailed investigations, about 30% of ischemic strokes remain unexplained. A percentage of these ischemic attacks may result from asymptomatic episodes of paroxysmal atrial fibrillation (PAF). Previous studies have demonstrated that electrophysiological testing and signal-averaged P wave (SAPW) ECG are useful to detect patients with PAF. METHODS AND RESULTS: Twenty patients with unexplained ischemic strokes had electrophysiological studies (EPS) to determine atrial vulnerability and SAPW recordings. At EPS, patients were classified in group I (10 patients) if they had a latent atrial vulnerability index < 2 and/or more than 1 minute of sustained atrial arrhythmia. Otherwise they were classified in group II (10 patients). In group I, the filtered P wave duration was greater: 142 versus 120 msec (P = 0.03) and RMS 30 tended to be lower: 2.54 versus 4.13 microV (P = 0.11) than in group II. A filtered P wave duration > 125 msec associated with a RMS 30 < 3 microV had a positive predictive value of 78% and a negative predictive value of 88% for the detection of patients with abnormal atrial vulnerability at EPS. CONCLUSIONS: SAPW may be useful to identify patients at risk of PAF who may be candidates for EPS.

Atrial Fibrillation↗

PubMed1994

Clinical significance of white-coat hypertension.

DEFINITION AND PREVALENCE OF WHITE-COAT HYPERTENSION: White-coat hypertension describes the phenomenon of an abnormal blood pressure reading when taken by a physician and a normal reading with ambulatory or home monitoring. The results of studies suggest that the true prevalence of white-coat hypertension may be 20%. The magnitude of the effect using either the oscillometric or the auscultatory method of measurement appears to be comparable. PROGNOSTIC SIGNIFICANCE: The prognostic significance of the white-coat effect is not established, and prospective trials are needed to assess the risk. At present, because of the unpredictability and unreliability of this effect, we recommend that patients with white-coat hypertension should not be included in trials on the efficacy of antihypertensive drugs.

Blood Pressure Determination↗

PubMed1994

[Ambulatory measurement of Korotkoff sounds timing (QKD interval) in a normal population].

Ambulatory monitoring of Korotkoff sounds appearance time (QKD interval) was performed during 24 hours in 131 normal subjects (85 males, 46 females, aged 14-78 years, mean 36 +/- 15 years) with a new device (Diasys 200RK, Novacor-France). This device allows simultaneous measurements of blood pressure, heart rate and QKD interval at programmed intervals, every 15 minutes in this study. For each patient we calculated the average 24th QKD interval, the QKD interval for a systolic BP of 100 mmHg and a heart rate of 60 bt/min (QKD: 100-60), and the slope (S) of the variations of the QKD interval against systolic BP and pulse pressure (PP). Results are presented for each 10 years age group (mean +/- SD).

Adolescent↗

PubMed1994

[Atrial fibrillation, restoration of sinus rhythm].

Conversion to sinus rhythm (cardioversion) is recommended to prevent the haemodynamic and thromboembolic complications of atrial fibrillation. Prior anticoagulation is compulsory except in emergencies. The duration of anticoagulant therapy depends on the terrain and chronicity of the arrhythmia. Cardioversion may be proposed for the majority of patients in whom it is thought that sinus rhythm can be maintained by appropriate therapy. It may be carried out pharmacologically by oral or intravenous antiarrhythmic therapy. Amiodarone is the drug of choice. Cardioversion may also be carried out by external or internal direct current shock. The success rate of external electrical defibrillation depends on the energy administered, the site of the electrodes and a number of factors related to thoracic impedence. Internal electrical defibrillation may be performed with an endocavitary catheter or by the oesophageal approach, with few complications. The main problem resides in maintaining sinus rhythm in the long term. When this is not possible, cardioversion is useless, and therapy to slow the cardiac rhythm should be instituted.

Amiodarone↗

PubMed1994

[Normal blood pressure profiles during exercise according to age, sex and protocols].

Systolic and diastolic blood pressure profiles of 2,808 healthy subjects are reported according to age, sex and exercise protocols. The rates of increase of systolic pressures are expressed with respect to the heart rate and decrease with age. For a given sub-maximal effort the systolic blood pressure is lower in males and in the younger age groups: the diastolic blood pressure only increases significantly on exercise after 50 years of age. These variations according to age and sex were confirmed on treadmill exercise but the peak pressure values were lower. These quantitative results differ from those of previously reported studies and suggest that the diagnostic criteria of hypertension of effort should be redefined.

Adult↗

PubMed1993

Ventricular arrhythmia revealing mitochondrial myopathy in a 69-year-old woman.

We report a case of mitochondrial myopathy (MM), assessed by histological and biochemical studies. This illness was diagnosed in a 69-year-old patient with myocardiopathy revealed by ventricular arrhythmias. The originality of this case lies in the patient's age, the mode of onset and the biochemical features (i.e. normal mitochondrial enzymatic complexes but very low respiration when using glutamate as a substrate).

Aged↗

PubMed1993

Left ventricular hypertrophy: epidemiological prognosis and associated critical factors.

Left ventricular hypertrophy (LVH), defined as an abnormal increase in left ventricular mass (LVM), is detected by echocardiography in 16-19% of a general population. Its prevalence is strongly associated with age, systolic blood pressure and obesity. In addition to the assessment of LVM, echocardiography allows different forms of left ventricular remodelling in hypertension to be described: eccentric or concentric, and symmetric or asymmetric LVH. The significance of the different forms, however, is not yet well defined. Increased LVM is now recognized as a powerful, independent risk factor for all cardiovascular diseases. This observation is at variance with the general concept that LVH is a useful adaptation of the left ventricle to chronic overload. To explain this paradox, three hypotheses are proposed: LVH serves as a marker, a limited adaptative process, or a pathological process. Each hypothesis implies different therapeutic approaches; thus it is necessary to clarify the reasons why LVH is such an important risk factor.

Adult↗

PubMed1993

'White coat' hypertension. No harm for the heart.

The superiority of ambulatory blood pressure monitoring over casual blood pressure measurement for the prediction of target-organ damage is now well established, although the significance of "white coat" hypertension is still controversial. Is an office blood pressure measurement that is higher than the mean ambulatory value an added risk? Because left ventricular hypertrophy is a potent risk factor, the effect of hypertension on left ventricular mass merits attention. Left ventricular mass indexed for height was measured by M-mode echocardiography in 204 essential hypertensive patients (140 males, 64 females; mean age [SD], 50 [11] years). Blood pressure over 24 hours was monitored routinely with a noninvasive auscultatory device. Office blood pressure after 10 minutes of the subject in the supine position was measured by the same physician under the same conditions. The white coat effect was defined as the difference between the office and average daytime values of systolic and diastolic blood pressures. Patients were divided into four quartiles according to their office and daytime blood pressures. Two-way analysis of variance was used to assess the influence of the white coat effect at a given level of daytime blood pressure on left ventricular mass. Left ventricular mass increased significantly (P < .001) with daytime systolic blood pressure but was independent of white coat effect for both the whole population and the 143 untreated patients. We conclude that the white coat effect has no influence on left ventricular mass, favoring the view that white coat hypertension is a benign condition.

Adolescent↗

PubMed1993

[Mechanisms of ventricular tachycardia].

There are three fundamental mechanisms of ventricular tachycardia (VT) reentry, abnormal automaticity and triggered activity (TA) related to early or late after potentials. Reentry is certainly the mechanism of branch to branch and post-infarction VT. Early TA is responsible for Torsades de Pointes. Late TA is possibly the cause of certain verapamil-responsive VT but calcium-dependent reentry cannot be excluded. Abnormal automaticity or late TA may also play a role in catecholamine-induced VT. The development of drugs specific for the mechanism confronted with the results of programmed stimulation and mapping should improve the understanding of the mechanism of VT in each individual patient and allow more effective and better tolerated antiarrhythmic therapy.

Cardiomyopathy, Dilated↗

PubMed1993

[Value of protocol using standardised activities of daily living for the programming of rate responsive pacing].

To optimise the regulation of rate responsive pacemakers, the authors propose standardized tests of everyday activities. Seven tests were selected with monitoring of the heart rate (HR) by telemetry every 30 seconds: two reference tests--cycloergometry: 2 steps of 3 minutes at 30 then 60 watts and a symptoms-limited Bruce protocol on the treadmill--and 5 everyday activities, walking, going upstairs, going downstairs, squats and hyperventilation. Fifteen normal subjects (65 +/- 10 years) were used to establish normal values and 10 patients implanted with a Telelctronics Meta DDDR 1250 rate responsive pacemaker with minute ventilation sensing, were studied after choice of minimal and maximal HR on clinical criteria (age, pathology). The rate response frequency (RRF) was adjusted so that the pacemaker HR was within normal values. At the beginning of each test, the sensor was hypokinetic (p = 0.01). Hyperventilation caused hyperkinesia of the sensor (p = 0.01). A good correlation was obtained between PM patients and normal subjects on walking, going up down stairs and for squats (p = NS). On cycle ergometry and treadmill, the PM remained slightly hypokinetic (p = 0.02). The study of "ideal" RRF measured at "peak exercise" as proposed by the manufacturer was only satisfactory in 1 of the 10 cases. This study confirms the value of using everyday activities for programming rate responsive pacemakers, the limitations of automatic adjustment and the need for personalized programming.

Activities of Daily Living↗

PubMed1993

[Diagnostic contribution of transesophageal echocardiography in infectious endocarditis. Apropos of 101 cases].

One hundred and one consecutive patients with infectious endocarditis were examined by transthoracic (TTE) and transoesophageal echocardiography (TEE). There were 71 cases of endocarditis on native valves (N) and 30 cases of endocarditis on prosthetic valves (P). The detection of vegetations was significantly greater by TEE (93%), than by TEE (73%) on native valves but the rate of detection of endocarditis on prosthetic valves was low and identical with both methods. Out of a total of 18 abscesses, only 6 were detected by TEE compared with 15 by TEE. There were 3 false negative results by TEE: small anterior abscesses marked by the prosthesis or aortic calcifications. In addition, TEE demonstrated 3 perforations and 2 mycotic aneurysms of the mitral valve. The lesions were confirmed anatomically in 48 cases. The sensitivity of TEE was 94% and the specificity was 84.5%; the negative predictive value was 87.5%. These results show that TEE is significantly superior in the detection and morphological analysis of vegetations. It is the method of choice for the diagnosis of abscesses, especially in prosthetic valve endocarditis.

Adolescent↗