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P Ritter

Publications and source records attributed to P Ritter.

At least 55 records · Page 3Linked to original sources
PubMed1994

A new pacing algorithm for overdrive suppression of atrial fibrillation. Chorus Multicentre Study Group.

Constant rapid pacing may suppress arrhythmias, but it is usually poorly tolerated in the long term. We report a pilot study of a new pacing algorithm for overdrive suppression of atrial premature complexes (APCs) and atrial fibrillation (AF), which prevents postextrasystolic pauses and varies the pacing rate in response to the frequency of APCs. The algorithm was tested in a multiple crossover study for 24 hours in dual chamber pacemakers implanted in 70 patients. Comparison was made on ambulatory recordings between the number of atrial arrhythmias commencing with the algorithm active and inactive. In all cases, the algorithm functioned as designed. No patient was aware of its operation, and no malignant arrhythmias were induced. The 36 recordings that showed atrial arrhythmia were included for analysis. The effects of the algorithm were: APCs (estimated from pacemaker statistics) reduced in 18 patients, increased in 8 (P = 0.02); atrial salvos reduced in 12, increased in 4 (P = 0.041); and AF reduced in 11, increased in 8 (P = NS). In all patients with frequent AF (> 5 episodes in total), fewer episodes occurred when the algorithm was active. We conclude that the algorithm is safe and well tolerated, reduces atrial ectopic activity, and may reduce the frequency of sustained atrial fibrillation.

Adult↗
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

Diagnosis of atrial arrhythmias using the Holter function of a new DDD pacemaker.

UNLABELLED: The extension of random access memory now makes it possible to store electrocardiographic (ECG) information, referred to here as Holter function (HF), in the memories of new pacemakers, which can be used as diagnostic tools during long-term follow-up. This report describes our experience in 26 consecutive patients for whom the device was used to detect episodes of atrial arrhythmias (AA). An illustrative case is also presented to describe in detail the device's analytical method. RESULTS: Fourteen AA profiles were successfully recorded in 10 patients by the pacemaker HF and correlated with confirmatory simultaneous surface ECG tracings. Three additional profiles were recorded in three other patients without simultaneous ECG recordings. A diagnosis of AA is established when the following findings are combined: (1) in all cases a large number of short interatrial intervals (A INT); (2) in presence of AV block, interventricular intervals (V INT) stored between the lower programmed pacing rate and the upper rate limit or the fallback rate; (3) in absence of AV block, V INT stored between the basic rate and the AV node refractory period; (4) in case of fallback, (VVI function) no stored AV INT; and (5) in absence of fallback, great variability of AV INT (Wenckebach function). CONCLUSIONS: (1) Diagnoses of AA can be made with the pacemaker HF; (2) The homogeneity of the HF profiles makes them useful for long-term follow-up and will probably contribute and clarify the natural history of AA in DDD patients; (3) HF may also serve to monitor the safety and efficacy of antiarrhythmic drug therapy during long-term follow-up.

Aged↗
PubMed1993

Comparison of open versus thoracoscopic lung biopsy for diffuse infiltrative pulmonary disease.

BACKGROUND: Patients with diffuse pulmonary infiltrates often require biopsy for a diagnosis. Standard operative therapy, open wedge resection via thoracotomy, is associated with known morbidity. We hypothesized that closed thoracoscopic wedge resection may result in reduced morbidity and decreased duration of hospital stay. This retrospective study compares open resection with thoracoscopic wedge resection in patients with diffuse pulmonary infiltrates. METHODS: Seventy-five patients with diffuse pulmonary infiltrates underwent diagnostic lung biopsy. Patients requiring mechanical ventilation and high levels of pressure support before biopsy were excluded from the study. Between March 1987 and September 1991, a total of 28 patients underwent open wedge resection via lateral thoracotomy. Since April 1991, a total of 47 patients underwent thoracoscopic resection. RESULTS: There was no difference between the groups in age, sex, presence of immunosuppression, or final pathologic diagnosis. Adequate tissue was obtained for pathologic diagnosis in all patients of both groups. All surgeons believed that thoracoscopic biopsy provided better visualization of the entire lung than did a limited thoracotomy. Mean operative time was 69 minutes for open biopsies and 93 minutes for thoracoscopic biopsies [p = 0.038]. Mean duration of chest tube drainage was not significantly different between the two groups. Duration of hospital stay was significantly less for thoracoscopic biopsy (4.9 days) than for open biopsy (12.2 days) (p = 0.018). Fourteen of 28 open biopsies resulted in complications compared with 9 of 47 closed biopsies (p = 0.009). There were 6 deaths among patients having open biopsies and 3 deaths among those having closed biopsies (p = not significant). CONCLUSION: A significant decrease in hospital stay was noted with thoracoscopic biopsy when compared with lung biopsy via the standard open approaches. Thoracoscopy provided excellent visualization and allowed for wedge resection that provided adequate tissue for diagnosis in patients with diffuse pulmonary interstitial disease.

Adult↗
PubMed1993

[Smoking among students of the CM2) (2d-year intermediate course): evaluation of knowledge and behavior].

This paper reports the results of a survey conducted on smoking among 1490 eleven years old schoolchildren. They answered to an individual questionnaire before and after they had been informed on smoking by school doctors. In this age group, 26.2% of the children have already had some contact with cigarette, and 0.5% smoke regularly. The household smoking habits have an important influence on the attitude of children toward smoking. Knowledges on smoking dangers have been evaluated before and after information. This survey shows the importance of smoking prevention, especially among young children.

Child↗
PubMed1992

[How are tumor markers used in diagnosis and in after-care of gastrointestinal cancers? Results of a nation-wide German survey].

To obtain appropriate information about the present use of tumor-associated antigens (TAA) in diagnosis and follow-up of gastrointestinal carcinomas, an inquiry into 102 German university and non-university hospitals was performed. 97 answers to ten standardized questions were available for evaluation. TAA are generally used in gastrointestinal carcinomas by 98.5% and 92.6% of internists (i) and surgeons (s), respectively. Preoperatively, serum concentrations of TAA are determined in 63.9% (i) and 84% (s) of gastric carcinomas. The corresponding rates in colorectal carcinomas are 93.8% and 92.6%. TAA are a routine part of postoperative care in 68.8% (i) and 76% (s) of gastric and in 100% (i) and 96.2% (s) of colorectal cancers. Interest is almost exclusively focused on CEA and CA 19-9. Other tumor associated antigens are rarely investigated in these diseases. Increasing serum concentrations of TAA induce intensive diagnostic procedures in 82.4% and 95.7% of internists and surgeons. However, an indication for a second-look operation solely based on increasing TAA concentrations is only seen by 30.6% of internists and 37% of surgeons. In gastric cancer the course of TAA concentrations is used for determining the effects of chemo- or radiotherapy in 36.4% (i) and 71.4% (s). The corresponding rates for colorectal carcinomas vary between 66.6% (i) and 80% (s). The results of this nation-wide inquiry confirm the wide use of CEA and CA 19-9 in gastrointestinal carcinomas. There are obvious differences with respect to diagnostic or therapeutic consequences based on postoperatively increasing serum levels of TAA.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1992

Atrial natriuretic factor release during exercise in patients successively paced in DDD and rate matched ventricular pacing.

Dual chamber pacemakers were implanted in nine patients with permanent second or third degree AV block (eight had complete retrograde block). Two identical exercise tests were performed after at least 1 month after implantation. During the first test (T1) the pacemaker was programmed to the DDD mode and heart rates were recorded every 15 to 30 seconds during exercise and 30 minutes after exercise. Following 30 minutes of rest, the implanted pacemaker was programmed to the VVT mode and driven by an external pacemaker via a skin electrode. The second exercise test (T2) was then performed and the rate of the external pacemaker was progressively changed to reproduce exactly the rate observed during T1 at the same exercise stress. Atrial natriuretic factor (ANF) levels were determined at rest, at regular intervals during exercise, and 30 minutes after exercise. ANF levels and release were statistically higher during rate matched ventricular, than DDD pacing. It is concluded that preservation of AV synchrony reduces ANF release induced by heart rate acceleration during exercise.

Aged↗
PubMed1992

[Value of an algorithm of automatic adaptation of the atrio-ventricular delay to the instantaneous atrial rate in cardiac stimulation].

It has been suggested that an algorithm of automatic adaptation of the AV delay to the instantaneous atrial rate be introduced into the program of DDD pacemakers to reproduce the physiological adaptation of the PR interval to effort, characterised by progressive shortening inversely linearly related to the heart rate. In order to evaluate the potential benefits in conditions of "standard" programming (basal AV delay the same for all patients: maximal frequency of 1/1 AV synchronisation uniformly limited to 120 bpm), a haemodynamic study was undertaken in 10 patients who had permanent DDD pacemakers implanted for advanced AV block. Measurements were taken during two standardized exercise stress tests (20 W/2 mn steps from an initial load of 20 W) performed in a random order, one with a fixed AV delay of 156 ms and the other with an "automatic AV delay" allowing linear reduction from a maximum value of 156 ms at rest to a minimum value of 84 ms at the maximum heart rate of 120 bpm. At the peak of exercise the "automatic AV delay" significantly affected 4 parameters: the paced ventricular rate (p = 0.008) and rate-pressure product (p = 0.005) which increased, pulmonary capillary pressure (p = 0.03) and cycle-to-cycle variability of systolic and diastolic blood pressures (p = 0.02 < p < 0.0001) which decreased. There was a tendency (NS) to slowing of the spontaneous atrial rate and to increase in cardiac output. This increase was significant in some patients and seemed to be due to a good relationship between the individual optimal value of the value basal AV delay measured by Doppler echocardiography and the value programmed in this study (156 ms).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

[Environment and permanent cardiac pacing].

The increasing technological sophistication of cardiac pacemakers make them potentially more vulnerable to electrical interference. The clinical consequence are of variable importance depending on the type of pacemaker and the nature of the interference. Electrical interference is present in the domestic, industrial and, above all, the medical environment. Apart from controlling the sources of emission, prevention requires standards of protection for the casing and electronic circuitry. Patient education remains primordial.

Electric Countershock↗
PubMed1991

[New cardiac pacemakers].

Because of the extraordinary technological progress made over the past years in pulse generators, the objective and indications of definitive cardiac pacing have greatly changed. All the different advantages are aimed at mimicking the electrophysiological and mechanical conditions of normal heart function. We have seen the development of: DDD mode dual chamber pacemakers, which in cases of AV block recreate normal AV synchrony; single chamber rate-responsive units piloted by an external captor responding to the organism's metabolic needs (intra-corporal vibrations resulting from exercise, respiratory rate, minute ventilation, QT interval, central temperature, SV O2...); they provide effective correction of atrial (AAI-R mode) or ventricular (VVI-R mode) chronotopic incompetencies often associated with chronic conduction disorders which make it impossible for patients paced in VVI or AAI mode to adapt heart rate to exercise level; and finally, "universal" pacemakers capable of pacing in all the single or dual chamber modes with rate responsiveness to one or several captors. These new pacemakers offer adaptability to the paced patient's needs as they vary throughout his lifetime. These units will probably be the "standard" cardiac pacemakers of the future.

Arrhythmias, Cardiac↗
PubMed1991

[Leg amputation as a result of attempted voluntary abortion].

The authors looked at the clinical situation and the possible pathogenicity which in this case was almost certainly traumatic. It would explain the total absence of one leg at the delivery of a baby who had no other psychomotor changes. They used this very exceptional case history of the loss of the lower limb after an attempt at terminating a pregnancy to study the matter from the French and foreign bibliography on the subject, which anyhow is very short. There was an attempt to terminate a pregnancy at an undisclosed duration of amenorrhoea (between 9 and 13 weeks) by suction evacuation followed by curettage. On the medico-legal side the authors analysed the reasons why there was no penal indictment brought at the same time as the civil action was brought prosecution, and also points out that the Conseil d'Etat decided, contrary to the Administrative Tribunal who were petitioned as to the responsibility for the serious handicap this child suffered to be established publically. They analysed the evolution of judicial and administrative jurisprudence on the matter of failure to terminate a pregnancy. The authors list other possibilities for traumatising a fetus in utero when the inside of the uterus is explored either when the pregnancy is a spontaneous pregnancy or an assisted reproductive pregnancy. The cases of pregnancy requiring a reduction in the number of embryos who will be born or the destruction of handicapped children whose legal status seems not only to be recognised at birth, but even in utero by the judges of the supreme administrative court.

Abortion, Induced↗
PubMed1991

[Aneurysm of a saphenous vein aortocoronary shunt caused by fissure syndrome].

The authors report a new case of an aneurysm of a saphenous vein aorto-coronary shunt. The aneurysm manifested itself by a fissure syndrome in a man 48 years of age, 9 years after myocardial revascularization surgery. A chest X-ray revealed a right paracardiac opacity, and two-dimensional ultrasound picked up an expansive, hypoechoic mass. The diagnosis was confirmed by coronary artery angiography. The aneurysm was opened up and the proximal anastomosis sutured. After a follow-up period of 30 months, the patient is asymptomatic.

Aneurysm↗
PubMed1991

Intraperitoneal mitoxantrone as consolidation treatment for stage III ovarian carcinoma: a pilot study.

In June 1986 we initiated an intra-peritoneal (IP) mitoxantrone chemotherapy trial as consolidation treatment for ovarian carcinoma in CR or PR after induction therapy (surgery + CHAP combination chemotherapy). Thirty-two patients received 25 mg IP mitoxantrone every 3 wk for 6 months. The most frequent side-effects were abdominal pains; haematological toxicity was minimal. The response was assessed by third-look surgery. In group I patients (patients in histological complete remission at second-look surgery) 12 of 14 evaluable patients remained in CR at the time of third look. Ten of the 12 patients are still alive with no evidence of disease (NED) with a median follow-up of 9.7 months after completion of treatment. In group II patients (microscopic residual disease at second-look surgery), 7 of 9 evaluable patients entered in CR at the time of third look; 6 of the 7 are still alive with NED and with a median follow-up of 14.3 months. In 7 group III patients (macroscopic residual disease at the time of second look) no response to IP therapy was observed and all patients progressed. We conclude that IP mitoxantrone is a valuable consolidation treatment for patients in CR or with minimal residual disease; further follow-up is necessary to assess the impact on duration of remission and survival.

Adult↗
PubMed1990

Dynamic electrophysiology of ventriculoatrial conduction: implications for DDD and DDDR pacing.

The behavior of ventriculoatrial conduction (VAC) during exercise remains unknown. In order to determine its characteristics and the consequences it might have on dual chamber pacemaker technology and programming, 17 patients underwent an electrophysiological study (EPS) of atrioventricular conduction (AVC) and of VAC during a protocol including three steps: supine rest, upright position, and finally during cycloergometric exercise; the measurements were done at progressively increasing pacing rates. During a preimplantation EPS, Wenckebach points AVC-W and VAC-W and conduction times, AVCT and VACT (as a function of pacing rate), were measured in ten consecutive patients using temporary leads and an external device. In another study, AVCT, VACT, AVC-W, and VAC-W were measured by telemetric recordings under identical conditions in seven patients implanted earlier with a DDD pacemaker. A 1/1 VAC was observed in 7/17 patients (41%) at rest, and in 13/17 patients (76%) at the end of the protocol; VAC was never observed in 4/17 patients (23%), but occurred in six of the ten patients initially free, three standing at rest and three on exercise. For all patients, the VAC behavior remained of "nodal" type, indicated by a progressive increase in VACT as pacing rate rose up to the VAC-W point. Neither the existence of exercise-induced VAC nor the maximal VACT-W could be predicted from AVC or VAC data obtained at rest. However, at the same pacing rates, standing up and exercise induced a shortening effect on VACT, and improved the VAC-W by an average of 33%. These results suggest that the electrophysiological behavior of VAC does not obey any general rule and cannot be predicted individually. It would thus appear unwise to base pacemaker mediated tachycardia (PMT) protection solely on long postventricular atrial refractory period (PVARP) programming in DDD patients. This work also revealed the potential risks of a rate responsive auto-adaptive PVARP algorithm as proposed in certain new devices.

Adult↗
PubMed1990

Assistant programming software: a new tool for an improved programming of pacemakers.

Programming the new DDD pacemakers is becoming increasingly difficult. One must take into account the pacemaker's complexity, the fact that some parameters are linked to others, and the clinical profile of the patient. This difficult problem will lead to the design of software to assist programming, which will help the implanting physicians in choosing adequate programmed settings adapted to the functioning of the device and to the physiology and pathology of the patient. These programming aides should meet certain basic requirements to make them safe, efficient, and easy to use. One such system designed by ELA Médical, "Programming Assistant" is herein described. The preliminary results of an initial study on the acceptance of this programming aide among physicians involved in cardiac pacing are given and discussed.

Adult↗
PubMed1990

Improved dual chamber pacing mode in paroxysmal atrioventricular conduction disorders.

Dual chamber pacing may sometimes be directly indicated for carotid sinus hypersensitivity, vasovagal syndrome, and certain cases of sinoatrial block and intermittent atrioventricular (AV) block, although AV conduction is dominantly normal. At times of normal AV conduction, competition between ventricular pacing and spontaneous ventricular depolarization may occur, with its adverse hemodynamic effects on ventricular function and unnecessary drainage of pacemaker battery energy. A new mode of stimulation is described, called automatic DDD mode, which functions in 'pseudo-AAI' mode during normal AV conduction and reverts to classical DDD function during episodes of AV blocks. Furthermore, during pseudo-AAI function, the pacemaker measures certain physiological parameters that serve to automatically program certain parameters used in DDD mode. Preliminary clinical evaluation has shown that this new mode functions satisfactorily.

Atrioventricular Node↗