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J C Daubert

Publications and source records attributed to J C Daubert.

At least 55 records · Page 3Linked to original sources
PubMed1998

Permanent left ventricular pacing with transvenous leads inserted into the coronary veins.

This paper describes a preliminary experiment-conducted jointly by 2 centers-of permanent left ventricular pacing using leads inserted by the transvenous route and through the coronary sinus into the cardiac veins of the left ventricle free wall. The aim was to obtain permanent biventricular pacing in a totally endocavitary configuration in patients with severe LV dysfunction and drug-refractory heart failure. Two types of leads were used: nonspecific unipolar leads at the beginning of the experiment, followed by leads specifically designed to be used in the coronary sinus in a second step. The electrode could be fitted in an adequate location in 35 of the 47 patients (75.4%), with a 1.15 +/- 0.7 V acute pacing threshold and 11.8 +/- 5.7 mV R wave amplitude. The success rate was significantly higher with the specific electrodes (81.8% vs 53.3%, p < 0.001). The pacing and sensing thresholds upon implantation were not influenced by the type of lead or by the localization of the cardiac vein that was catheterized (great cardiac vein, lateral vein, postero-lateral or posterior vein, mid cardiac vein). In contrast, the pacing threshold was significantly lower (0.8 +/- 0.2 vs 1.8 +/- 0.8 V; p = 0.002) and the R wave amplitude tended to be greater (13.1 +/- 4.5 mV vs 9.3 +/- 6.5 mV; p = 0.07) when the tip electrode could be inserted distally into the vein, by comparison with a proximal site near the ostium. At the end of follow-up (10.2 +/- 8.7 months), 34 out of the 35 leads were still fully functional, with a chronic pacing threshold of 1.8 +/- 0.7 V and a R wave amplitude of 10.7 +/- 6 mV. To conclude, permanent LV pacing via the transvenous route is possible in most patients, with excellent safety and long-term results.

Aged↗
PubMed1997

Preliminary clinical experience with the first dual chamber pacemaker defibrillator.

The lack of specificity of VT detection is a significant shortcoming of current ICDs. In a French multicenter study, 18 patients underwent implantation of the Defender 9001 (ELA Medical), an ICD utilizing dual chamber pacing and arrhythmia detection. Over a mean follow-up period of 7.1 +/- 4.5 months, 176 tachycardia episodes recorded in the device memory were analyzed, and physician diagnosis was compared with that by the device. All 122 VT/VF episodes were correctly diagnosed, as were 51 of 53 supraventricular tachyarrhythmias. Two episodes of AF with rapid regular ventricular rates were treated as VT, and a third episode, treated as VT, could not be diagnosed with certainty. A dual chamber pacemaker defibrillator offers improved diagnostic specificity without loss of sensitivity, in addition to the hemodynamic benefit of dual chamber pacing.

Adolescent↗
PubMed1994

Four chamber pacing in dilated cardiomyopathy.

A 54-year-old man received a four chamber pacing system for severe congestive heart failure (NYHA functional Class IV). His ECG showed a left bundle branch block (200-msec QRS duration) with 200-msec PR interval, normal QRS axis, and 90-msec interatrial interval. An acute hemodynamic study with insertion of four temporary leads was performed prior to the implant, which demonstrated a significant increase in cardiac output and decrease of pulmonary capillary wedge pressure. A permanent pacemaker was implanted based on the encouraging results of the acute study. The right chamber leads were introduced by cephalic and subclavian approaches. The left atrium was paced with a coronary sinus lead, Medtronic SP 2188-58 model. An epicardial Medtronic 5071 lead was placed on the LV free wall. The four leads were connected to a standard bipolar DDD pacemaker, Chorus 6234. The two atrial leads were connected via a Y-connector to the atrial channel of the pacemaker with a bipolar pacing configuration. The two ventricular leads were connected in a similar fashion to the ventricular channel of the device. The right chamber leads were connected to the distal poles. The left chamber leads were connected to the proximal poles of the pacemaker. Six weeks later, the patient's clinical status improved markedly with a weight loss of 17 kg and disappearance of peripheral edema. His functional class was reduced to NYHA II. Four chamber pacing is technically feasible. In patients with evidence of interventricular dyssynchrony, this original pacing mode probably provides a mechanical activation sequence closer to the natural one.(ABSTRACT TRUNCATED AT 250 WORDS)

Bundle-Branch Block↗
PubMed1994

Surgery for aortic stenosis in elderly patients. A study of surgical risk and predictive factors.

BACKGROUND: Aortic stenosis is the most common valvular lesion occurring among elderly patients and has become extremely frequent because of changing demographics in industrialized countries. Surgical risk after the age of 70 has increased. The increasing older age of patients having surgery justifies an analysis of mortality predictive factors. METHODS AND RESULTS: Between 1976 and February 1993, we performed 2871 operations for aortic stenosis. This study concerns 675 patients (278 men and 397 women) who were > or = 75 years old. Mean age was 78.5 +/- 3 years. Associated lesions were found in 226 patients. A bioprosthesis was implanted in 632 patients (93.6%). Concomitant surgical procedures were performed in 133 patients. Surgical mortality was 12.4% (84 deaths). A longitudinal analysis has been carried out over four successive time periods to evaluate population evolution during these 17 years. Statistical analysis was performed on 46 variables. Multivariate analysis found age (P < .0001), left ventricular failure (P < .0001), lack of sinus rhythm (P < .01), and emergency status (P < .02) to be presurgical independent predictive factors of mortality. CONCLUSIONS: Risk-reducing strategy should both favor relatively early surgery to avoid cardiac failure and emergency situations and pay careful attention to the use of myocardial protection and cardiopulmonary bypass. Indications for surgery should remain broad since analysis failed to determine specific high-risk groups to be eliminated, and surgery remains the only treatment for aortic stenosis.

Age Factors↗
PubMed1993

[20 years of mitral valve replacement. Development of a patient profile and operative mortality].

Between 1971 and 1991, 1,179 mitral valve replacements (MVR) were carried out in 1,134 patients. The sex ratio was stable over this period (0.7 men/women) whereas the average age of the patients increased by 10 years (50 years in 1971, 61 years in 1991). Since 1980, patients over 60 years of age represent about 60% and those over 70 years of age 16 to 22% of the population. The functional status of the patients has tended to be less severe, the NYHA stages III and IV which were initially preponderant, only represent 50 to 60% of patients operated nowadays. This reduction in the severity of symptoms is reflected in the average value of the cardio thoracic index which was 60 in 1971 and 54.8 in 1991. Similarly, the mean pulmonary artery pressures (measured in 823 patients, 69.8%) have decreased from 37.4 mmHg in 1971 to 29.9 mmHg in 1991. Rheumatic fever has tended to be replaced by degenerative etiologies which, since 1985, represent 40 to 50% of cases. Ischemic mitral regurgitation rare before 1980, is more common, presently making up 5 to 15% of MVR cases. In relation with the etiological changes mitral stenosis is giving way to mitral regurgitation as the commonest valve lesion (40 to 50% of cases in 1991). The annual operative mortality is lower (6 to 8%) than in 1982, despite the increasing number of emergency cases (7 to 10% of cases since 1985). The number of MVR with associated tricuspid valve repair has decreased with respect to isolated MVR or associated with aortocoronary bypass grafting. The only constant feature is the death rate due to myocardial dysfunction which remains over 50% whereas mortality related to the prosthetic valves varied over the years.

Age Factors↗
PubMed1992

Is polyurethane lead insulation still controversial?

A controversy arose some 10 years ago over the reliability of polyurethane lead insulation. On the basis of one of the longest standing and largest databanks worldwide, the authors compare the cumulative survival of several thousand polyurethane, standard silastic, and high-performance silastic electrodes as it pertains to the failure criterion described as insulation degradation. With the possible exception of the Medtronic 6972 (Medtronic, Inc.) electrode, polyurethane electrodes have a 100% reliability at 84 months, which is similar to silastic electrodes.

Databases, Factual↗
PubMed1992

Failure of epinephrine to induce severe cardiac arrhythmia in rats with ventricular hypertrophy secondary to aortic pressure overload.

The arrhythmogenic action of epinephrine was studied in 3 groups of rats: 10 rats with mild constriction of the abdominal aorta (group H1), 10 rats with severe constriction (group H2), 10 sham-operated age-matched rats (group C). Blood pressure and ECG were recorded before, during and after 5 min. perfusion of increasing doses of epinephrine (1, 5, 10 and 25 micrograms.kg-1.min.-1). Ventricular arrhythmia was evaluated from the ECG using a modified Lown's grading system. The ventricular hypertrophy index was calculated from the heart/body weight ratio (mg/g). The mean arterial blood pressure was significantly higher in groups H1 and H2 than in the control group. The ventricular hypertrophy was significant in group H2, but not in group H1. There was no significant difference between the amplitudes of the epinephrine-induced hypertensive responses in the 3 groups but the extent of arrhythmia was significantly lower in the animals with high hypertrophy index.

Animals↗
PubMed1992

[Arrhythmogenic cardiomyopathies of the right ventricle].

Arrhythmogenic cardiomyopathies of the right ventricle (ACRV) are defined by an association of left delayed type ventricular arrhythmias, ranging from apparently uncomplicated extrasystoles to more severe or even potentially lethal arrhythmias such as polymorphous VT and ventricular fibrillation, with an anatomical substrate consisting of adipose or fibro-adipose degeneration of the myocytes of the free wall of the ventricle, which may be either focal (in particular: apex, anterior surface of the infundibulum and the sub-tricuspid region), or more diffuse. It is then accompanied by RV systolic dysfunction with dilatation of the cavity. This apparently well defined clinico-pathological entity is in fact more complex, if only because of the existence of associated lesions of the left ventricle in 1/3 of cases. The distinction from Uhl disease remains blurred, in particular in diffuse forms. It is most probable that more than one etiology is involved. A dysgenetic mechanism with probable autosomal dominant transmission has apparently been shown in familiar forms which are associated with a particularly severe risk of progression. The hypothesis of sequelae of multifocal myocarditis appears to be the most probable in sporadic forms. In the absence of histological criteria, which it is difficult to demand in view of the variability of results and potential dangers of endomyocardial biopsy involving such thin and fragile ventricular walls, the diagnosis of ACRV is based upon the concomitant existence of: (1) electrophysiological criteria: ventricular arrhythmias, in particular sustained monomorphous VT, with the particular feature of a very high degree of sensitivity to adrenergic stimulation (exercise), the existence of late potentials on the high amplification ECG, a highly specific sign, though unfortunately of poor sensitivity in localized froms, those which are most difficult to identify (2); segmentary morphological and kinetic RV abnormalities, most often resulting in localized akinetic or dyskinetic parietal vaulting, with stasis "in situ". Modern imaging methods (echocardiography, angioscintigraphy with phase analysis, nuclear magnetic resonance imaging, etc.) unfortunately do not yet offer an alternative to selective cineangiography of the RV which is the reference investigation when it is performed and interpreted under strict conditions. Several reports of sudden death or of ventricular fibrillation seen in confirmed cases of ACRV, as well as the publication of a number of autopsy registers indicating that this condition is one of the primary causes of sudden death in young individuals and in athletes, have cast doubt on the benign prognosis initially attributed to this condition.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1992

[Isolated myocardial infarction in the right ventricle: clinical and echocardiographic study].

The purpose of this study was, on the basis of 4 cases of isolated infarction of the right ventricle (RV), to describe the clinical profile of this disorder and compare the value of ultrasonography with other invasive methods of investigation (hemodynamic and kinetic angiocardiographic methods) in diagnosis and evaluation of the prognosis. In all cases the clinical situation was indicative: prolonged chest pain, slight enzymatic peak, downward shift of the ST segment in V3R and V4R. The diagnosis was rapidly confirmed by ultrasound in the face of the abnormal isolated segmental kinetics in the RV, associated with cavity dilatation and tricuspid incompetence. These data were consistent with those of RV kinetic angiography. Right cardiac catheterism showed the classical signs of adiastolism with no reduction in heart rate, except in one case. The outcome was generally simple. Ultrasound revealed the regression of the abnormalities of parietal kinetics. Thus, ultrasound examination is shown to be a method of exploration which is easy to perform and effective in the diagnosis of this disorder with a good prognosis.

Aged↗