Implementation of a multidisciplinary infections conference improves the treatment of spondylodiscitis

Establishing a multidisciplinary approach regarding the treatment of spondylodiscitis and analyzing its effect compared to a single discipline approach. 361 patients diagnosed with spondylodiscitis were included in this retrospective pre-post intervention study. The treatment strategy was either established by a single discipline approach (n = 149, year 2003–2011) or by a weekly multidisciplinary infections conference (n = 212, year 2013–2018) consisting of at least an orthopedic surgeon, medical microbiologist, infectious disease specialist and pathologist. Recorded data included the surgical and antibiotic strategy, complications leading to operative revision, recovered microorganisms, as well as the total length of hospital and intensive care unit stay. Compared to a single discipline approach, performing the multidisciplinary infections conference led to significant changes in anti-infective and surgical treatment strategies. Patients discussed in the conference showed significantly reduced days of total antibiotic treatment (66 ± 31 vs 104 ± 31, p < 0.001). Moreover, one stage procedures and open transpedicular screw placement were more frequently performed following multidisciplinary discussions, while there were less involved spinal segments in terms of internal fixation as well as an increased use of intervertebral cages instead of autologous bone graft (p < 0.001). Staphylococcus aureus and Staphylococcus epidermidis were the most frequently recovered organisms in both patient groups. No significant difference was found comparing inpatient complications between the two groups or the total in-hospital stay. Implementation of a weekly infections conference is an effective approach to introduce multidisciplinarity into spondylodiscitis management. These conferences significantly altered the treatment plan compared to a single discipline approach. Therefore, we highly recommend the implementation to optimize treatment modalities for patients.

A human-centred assessment framework to prioritise heat mitigation efforts for active travel at city scale

Hot weather not only impacts upon human physical comfort and health, but also impacts the way that people access and experience active travel options such as walking and cycling. By evaluating the street thermal environment of a city alongside an assessment of those communities that are the most vulnerable to the effects of heat, we can prioritise areas in which heat mitigation interventions are most needed. In this paper, we propose a new approach for policy makers to determine where to delegate limited resources for heat mitigation with most effective outcomes for the communities. We use eye-level street panorama images and community profiles to provide a bottom-up, human-centred perspective of the city scale assessment, highlighting the situation of urban tree shade provision throughout the streets in comparison with environmental and social-economic status. The approach leverages multiple sources of spatial data including satellite thermal images, Google street view (GSV) images, land use and demographic census data. A deep learning model was developed to automate the classification of streetscape types and percentages at the street- and eye-view level. The methodology is metrics based and scalable which provides a data driven assessment of heat-related vulnerability. The findings of this study first contribute to sustainable development by developing a method to identify geographical areas or neighbourhoods that require heat mitigation; and enforce policies improving tree shade on routes, as a heat adaptation strategy, which will lead to increasing active travel and produce significant health benefits for residents. The approach can be also used to guide post COVID-19 city planning and design.

Could smart research ensure healthy people in disrupted cities?

BACKGROUND

Since the late 19th century, city planners have struggled to cope with new types of urban transport and mobility that threatened the existing system, or even rendered it obsolete.

PURPOSE

As city planners confront the range of disruptive urban mobilities currently on the horizon, this paper explores how we can draw on a vast body of evidence to anticipate and avoid unintended consequences to people's health and wellbeing.

METHODS

This commentary involved a rapid review of the literature on transport disruption.

RESULTS

We found that to avoid the unintended consequences of disruption, research, policy and practice must think beyond single issues (such as the risk of chronic disease, injury, or traffic management) and consider the broader consequences of interventions. For example, although autonomous vehicles will probably reduce road trauma, what will be the negative consequences for physical inactivity, sedentary behavior, chronic disease, land use, traffic congestion and commuting patterns? Research is needed that considers and informs how to mitigate the range of potential harms caused by disruptive mobilities.

CONCLUSION

In the face of new disruptive mobilities, we must: (a) draw on existing evidence to shape new regulations that address the 'who, when and where' rules of introducing new mobilities (such as electric assisted bicycles (e-bikes) and scooters (e-scooters)) of which the health repercussions can be easily anticipated; (b) monitor and evaluate the implementation of any interventions through natural experiment studies; and (c) use innovative research methods (such as agent-based simulation and health-impact-assessment modelling) to assess the likely effects of emerging disruptive mobilities (e.g., autonomous vehicles) on health and wellbeing and on the environment.

Implementation of a multidisciplinary infections conference affects the treatment plan in prosthetic joint infections of the hip: a retrospective study

INTRODUCTION

Establishing a systematic multidisciplinary approach in the treatment of prosthetic joint infections (PJI) of the hip and analyzing its effect on clinical decision-making.

PATIENTS AND METHODS

Forty-six patients diagnosed with PJI of the hip were included in the retrospective study. The treatment plan was either established by a single-discipline approach (n = 20) or by a weekly multidisciplinary infections conference (n = 26) consisting of at least an orthopedic surgeon, microbiologist and pathologist. Recorded data included the length of hospital stay, number and type of surgeries, medical complications, recovered organisms as well as the number of applied antibiotics.

RESULTS

Patients discussed in the multidisciplinary infections conference showed a significantly shorter in-hospital stay (29 vs 62 days; p < 0.05), a significant reduction in surgeries (1.8 vs 5.1; p < 0.05) and a smaller number of antibiotics required (2.8 vs 4.2; p < 0.05). No significant difference could be found comparing inpatient complications between the two groups. Staphylococcus aureus and coagulase-negative staphylococci were the most frequently recovered organisms in both patient groups.

CONCLUSION

This study demonstrates the successful implementation of a weekly infections conference as an instrument to introduce a multidisciplinary approach to PJI of the hip. Implementation of these conferences significantly improves the treatment plan compared to a single-discipline approach, which we therefore highly recommend for other institutions. Multidiscipline may even affect clinical outcome which needs to be further investigated.

Psychometric evaluation of a motor control test battery of the craniofacial region

The primary objective of this study was to determine the structural and known-group validity as well as the inter-rater reliability of a test battery to evaluate the motor control of the craniofacial region. Seventy volunteers without TMD and 25 subjects with TMD (Axes I) per the DC/TMD were asked to execute a test battery consisting of eight tests. The tests were video-taped in the same sequence in a standardised manner. Two experienced physical therapists participated in this study as blinded assessors. We used exploratory factor analysis to identify the underlying component structure of the eight tests. Internal consistency (Cronbach's α), inter-rater reliability (intra-class correlation coefficient) and construct validity (ie, hypothesis testing-known-group validity) (receiver operating curves) were also explored for the test battery. The structural validity showed the presence of one factor underlying the construct of the test battery. The internal consistency was excellent (0.90) as well as the inter-rater reliability. All values of reliability were close to 0.9 or above indicating very high inter-rater reliability. The area under the curve (AUC) was 0.93 for rater 1 and 0.94 for rater two, respectively, indicating excellent discrimination between subjects with TMD and healthy controls. The results of the present study support the psychometric properties of test battery to measure motor control of the craniofacial region when evaluated through videotaping. This test battery could be used to differentiate between healthy subjects and subjects with musculoskeletal impairments in the cervical and oro-facial regions. In addition, this test battery could be used to assess the effectiveness of management strategies in the craniofacial region.

[Hemostatic wound management in marcumar patients. Collagen fleece vs. tranexamic acid]

A total of 124 patients on oral anticoagulation therapy with coumarin were treated by orosurgical procedures and entered into a study to determine the hemostatic efficiency of different methods. The therapeutic anticoagulation level was determined in accordance with the recommendations of the American Heart Association (low risk: 2.0 < INR < 3.0; high risk: 2.5 < INR < 3.5) and maintained during treatment. In one group, the alveoli were treated with collagen, in a second group a mouthrinse regime with tranexamic acid was implemented. Twenty-three patients had to be excluded because anticoagulation levels differed from the recommended values. The group treated with collagen included 31 patients, the group with tranexamic acid mouthwashes, 32 patients. A third group was analyzed in which a controlled change in the anticoagulation level had been performed and all treated alveoli had been covered by mucosal flaps (n = 38); they were compared to the other two groups. The surgical proceedings were outlined precisely. Patients treated with collagen had a bleeding rate of 19%, patients with tranexamic acid mouthwash 6%, and those treated with mucosal flaps 40%. The data were not suited for statistical evaluation, they were objected to a descriptive analysis: the confidence intervals were determined by tables for binomial distributions. These did confirm the difference in the frequency of bleeding for the tranexamic acid and mucosal flap groups.

Sequential cycles of high-dose chemotherapy with dose escalation of carboplatin with or without paclitaxel supported by G-CSF mobilized peripheral blood progenitor cells: a phase I/II study in advanced ovarian cancer

To assess high-dose carboplatin chemotherapy with or without paclitaxel with filgrastim mobilized peripheral blood progenitor cell (PBPC) support in a phase I/II study, a total of 21 patients with mostly chemonaive disease received four cycles of high-dose chemotherapy. Cycle 1 (cyclophosphamide, 6 g/m2) was followed by two cycles of carboplatin (1600 mg/m2 or 1800 mg/m2). Cycle 4 consisted of carboplatin (1600 mg/m2), etoposide (1600 mg/m2), and melphalan (140 mg/m2). Further chemotherapy intensification was achieved by adding paclitaxel (175 mg/m2) to all cycles with a fixed carboplatin dose (1600 mg/m2). Ototoxicity was dose-limiting for escalation of sequential cycles of carboplatin. Grade 2 and grade 3 ototoxicity, hearing loss not requiring a hearing aid, or hearing loss correctable with a hearing aid, was observed with carboplatin at 1800 mg/m2. The maximum tolerated dose (MTD) of sequential carboplatin, therefore, was identified in this study as 1600 mg/m2. After cycles 1, 2, 3 and 4 the median duration of leukopenia (<1.0x10(9)/l) was 7, 4, 4 and 6 days. Severe grade 3 and 4 infections were seen in only 7% of cycles. Of the 21 patients evaluable for disease response, 57% had complete remissions and 43% experienced partial remissions resulting in an overall response rate of 100%. The median progression-free survival is 25 (15-36) months, the median overall survival 36.5 (15-38) months. Most patients were suboptimally debulked or had bulky residual disease at the start of chemotherapy. Sequential high-dose chemotherapy to a maximum dose of 1600 mg/m2 carboplatin is effective and feasible. A randomized, prospective trial comparing sequential high-dose chemotherapy with optimal standard chemotherapy is now warranted.

[Restrictive cardiomyopathy as a late sequel of influenza A2 virus myocarditis]

A clinically acute myocarditis with an increase of the influenza A2-virus titer marks the beginning of a ten year history leading to a restrictive cardiomyopathy, complicated by an exudative enteropathy. Two serial endomyocardial biopsies reveal an increasing interstitial fibrosis. Virus myocarditis as a cause of restrictive cardiomyopathy, which corresponds to the old term "myocardial fibrosis", is discussed.

[Cor triatriatum sinistrum in adults (case report)]

A case is presented of cor triatriatum sinistrum , which has been diagnosed in an adult. The findings of invasive and noninvasive studies have resulted in a diagnosis, which can be confirmed by using two-dimensional echocardiography.

[The information value of roentgen computerized tomography in atrial tumors of the heart]

The symptoms of intracavitary masses are usually not characteristic and are often confused with those of mitral valve disease. It is therefore necessary to employ all possible diagnostic measures. Like echo cardiography, computer tomography is a non-invasive method which provides accurate information concerning the size, position and shape of the mass. Angiocardiography can confirm these findings, but provides extra information only if there are additional abnormalities or coronary disease. Early diagnosis is important, since the patient is at risk from complications such as cardiac failure, emboli and arrhythmias, and since operative removal of the tumour carries a good prognosis.

[Isotopic study of cardiac hemodynamics after multiple valve prothesis (author's transl)]

The radiocardiography of the minimal transit times (MTTs) produces cardiologically useful hemodynamic data also in such instances where invasive techniques with the cardiac catheter are technically difficult, as is the case in patients with multiple valve prothesis. The present study reports on MTT measurements in 9 patients with tricuspidal prothesis, 8 of which had additional mitralvalve prothesis and 2 additional aortic valve prothesis. The measurements were made with Tc-99m Pertechnetate, and an Anger camera with electronic data processing was used as detector system. The results indicate that following implantation of valve prothesis the hemodynamic state remained essentially disturbed. The pathologically altered transit times are an expression of disturbed volume ratios. The transit times in the atria remained prolonged by an average factor of 4-5. The ejection of the left ventricle stayed diminished more pronounced than on the right. The values of one patient who was examined before and after implantation of the prothesis in mitral and tricuspidal position, also showed a worsening of the data especially in the atria. Because the cardiac function study with radioisotopes is non invasive, simple, and fast, and leads to only a minor radiation burden, the method may be repeated and without hazard used for control follow-ups.

[Evaluation of social status and hemodynamic results four to six years after prosthetic valve replacement (author's transl)]

In 72 patients the professional and social status before and after prosthetic valve replacement was examined. In 60 of these patients the hemodynamic data (cardiac index, stroke volume index, pulmonary arterial pressure at rest and during exercise) were measured. The patients were classified according to their professional training, their last occupation, and their social status before operation. Postoperative changes in professional life and the daily work load were correlated to the hemodynamic results. The study shows that the social status plays a more important role in regaining the professional position postoperatively than the hemodynamic parameter.

[Hemodynamics after mitral valve replacement with Starr-Edwards, Björk-Shiley and Lillehei-Kaster protheses (author's transl)]

After mitral valve replacement hemodynamic abnormalities persist. These abnormalities were studied 1 year postoperatively. In 50 randomized patients; 15 with Starr-Edwards (SEM), 15 with Lillehei-Kaster (LKM) and 20 with Björk-Shiley (BSM) prostheses at rest and during exercise. Simultaneously were determined: pulmonary arterial pressure, left atrial pressure, left ventricular enddiastolic pressure, mean diastolic pressure gradient across the prostheses, cardiac index, stroke volume index, valve orifice area, and ejection fraction. The results show an important stenosis by the prostheses leading to high pressure increase in pulmonary artery and left atrium during excercise. This stenosis depends on valve size and type. Björk-Shiley tilting disc valves show the best hemodynamic results. This may be due to the most favourable ratio between internal and external diameter. Starr-Edwards prostheses with identical sizes show the most identical results if compared to each other. Therfore we suggest that Starr-Edwards prostheses open completely in every case. However, there is an important pressure gradient caused by the small internal diameter. Lillehei-Kaster pivoting disc valves reach surprisingly small functional valve areas. This may be caused by an incomplete opening of the disc.

[Hemodynamic results after prothetic tricuspid valve replacement (author's transl)]

The hemodynamic results after prosthetic tricuspid valve replacement were investigated in 8 patients. One patient had myxoma in the right atrium with destruction of the tricupsid valve. 7 patients had multiple rheumatic valvular disease. In all these patients multiple valve replacement was performed. The pressure in the right and left atrium , the cardiac output, and stroke volume were determined in all cases at rest, in 5 patients also on exercise. Furthermore the subclavian venous blood flow was measured by Doppler ultrasound technique percutaneously. In all cases the pressure in the right atrium remained elevated after operation and increased on exercise with the increasing cardiac output. This pressure increase is due to an important obstruction of the prostheses to the blood flow. This could be demonstrated by determination of diastolic pressure gradients across the prostheses. In 5 cases the analysis of the pressure curves showed systolic elevation suspicious to tricuspid insufficiency. In all these cases a systolic regurgitation was seen in ultrasonic Doppler flow curves of the subclavian veins. This method seems to be of value in assessing tricuspid regurgitation after valve replacement. The hemodynamic results after prosthetic tricuspid valve replacement are unsatisfactory in most cases. Tricuspid valve replacement should be considered only in cases in whom valve-preserving procedures are not possible.

His bundle recordings in a case of complete atrioventricular block combined with pre-excitation syndrome

In a patient with complete A-V block suffering from attacks of dizziness an intermittent A-V conduction with a short P-R interval and a delta wave of the conducted ventricular complex were observed. After accelerating the sinus rate by atropine and by exercise, one-to-one conduction was established with QRS complexes of WPW type A configuration. His bundle recordings revealed a complete block within the normal conduction system at the level of the A-V node. A slow junctional rhythm with a normal H-V interval was activating the ventricle. During atrial pacing a one-to-one conduction through an accessory pathway could be documented at cycle lengths between 800 and 380 msec. sandwiched in between zones of complete block at smaller or longer cycle lengths. During ventricular stimulation no retrograde V-A conduction could be observed. The findings support the thesis of at least two functionally different A-V pathways in patients with pre-excitation syndrome.

[Surgical management of acquired tricuspid insufficiency--valvular replacement or annuloplasty? (author's transl)]

61 patient underwent operative repair of acquired tricuspid insufficiency (T.I.) during correction of multiple valvular disease. 45% presented a relative T.I. through annular dilatation, while organic lesions of the tricuspid valve were found in 56% of the patients. A tricuspid valvular replacement was carried out in 17, and a tricuspid annuloplasty in 44 patients. We believe that during surgical management of multiple valvular lesions, all tricuspid insufficiencies of even when only of a slight to moderate degree - should be corrected aggressively. Tricuspid valvular replacement should be avoided if possible and a tricuspid annuloplasty should be performed.

The effect of atropine on calculated sinoatrial conduction time in man

This study investigates the effect of atropine on the length of the return cycles after premature atrial stimulation in man. On the assumption that sinus node automaticity is not changed by premature depolarization of the sinus node, sinoatrial conduction time (SACT) was calculated from the differences between the length of the return cycles and the spontaneous cycle length. 11 patients were studied before and after the injection of atropine. In all cases atropine caused an increase in heart rate. In 8 patients the return cycles exhibited a typical behavior. In 6 patients without signs of sinus node dysfunction, the mean calculated SACT was 109 msec, whereas 2 patients with a sick sinus syndrome (SSS) had a mean calculated SACT of 190 and 225 msec, respectively. 3 patients with SSS demonstrated an atypical pattern of the postextrasystolic pauses. In 6 patients without sinus node dysfunction, atropine caused a reduction of calculated SACT about 35%. In 2 patients with SSS the reduction was 38 and 49% of the control value, respectively, whereas in the remaining 3 patients with SSS who had an atypical return cycle pattern, a normalization occurred after the administration of atropine. We conclude that, besides its effects on sinus node automaticity, atropine has also a marked effect on sinoatrial conduction, even in patients with the sick sinus syndrome.

Direct stimulation of the sinus node in man. A possible explanation for an unusual finding during premature atrial stimulation

An atypical behavior of the postextrasystolic pauses was observed in a 19-yr-old patient studied by His bundle electrography and programmed premature atrial stimulation. In the normal case there is a prolongation of the postextrasystolic pauses compared to the spontaneous cycle length allowing calculation of sinoatrial conduction time (SACT). In this case there were constant postextrasystolic pauses during the whole range of prematurity which were identical to the spontaneous cycle length. It is suggested that the catheter tip was accidentally positioned at the sinus node itself. The lengths of the spontaneous cycles, of the return cycles, and of the postreturn cycles showed no significant differences. Thus, one may assume that sinus node automaticity was not influenced in this case.

[Banding for pulmonary artery and subsequent repair in large ventricular septal defect (author's transl)]

Banding of the pulmonary artery was performed in 233 children with large, non restrictive ventricular septal defects. The group of isolated large VSDs consisted of 95 patients, of whom 8 died (8,4 per cent). 32 patients were subjected to open-heart operation for closure of the VSD and debanding. In this "two-stage group" the mortality rate was 6,3 per cent. At the second operation the pulmonary artery always should be enlarged with a pericardial patch. Our recordings up to 6 1/2 years after correction show no gradients left in cases surgically treated in this manner. The time-interval between effective banding and debanding procedure may not be limited strictly; the subsequent operation however should be done within two or three years.

[The effect of drugs on "sino-atrial conduction time" and on sinus-node automaticity in man]

The effect of atropine, propafenone, and disopyramide on sinus node automaticity and "sino-atrial conduction" was tested in normal patients and patients with the sick sinus-syndrome. "Sino-atrial conduction time" was estimated indirectly by the extrastimulus technique. Atropine (n = 11) caused a significant increase in heart rate in all patients. The sinus node recovery time was shortened in 10 patients. "Sino-atrial conduction time" decreased on an average 35% (P less than 0.01). Three patients with a sick sinus-syndrome demonstrated a change of the pattern of the postextrasystolic pauses indicating great improvement in sino-atrial conduction. Propafenone (n = 10) led to a significant prolongation of the sinus node recovery time by 17% and of the "sino-atrial conduction time" by 27%. Disopyramide (n = 8) had no significant influence on heart rate and "sino-atrial conduction time". Sinus node recovery time was not changed in 6 patients. However, in two patients with a sick sinus-syndrome a dangerous prolongation of the sinus node recovery time after application of disopyramide occurred. The results indicate that atropine enhances sinus node function and sino-atrial conduction. On the other hand, propafenone and disopyramide exert either a depressant influence on sinus node automaticity or on sino-atrial conduction.

[Electrophysiological effects of the antiarrhythmia agents disopyramide and propafenone on human heart conduction system]

The effect of Disopyramide and Propafenone on intracardiac conduction and refractory periods was tested by means of His bundle electrography and atrial stimulation. Disopyramide (1,7 mg/kg) was administered in 10 patients. There was no significant change of heart rate and conduction time within the atrium and the AV-node. The conduction velocity within the His-Purkinje system was significantly slowed by 13% of the control value. The ERP of the atrium as well as the ERP and FRP of the AV node were prolonged. Propafenone (1,7 mg/kg) was tested in 18 patients. The heart rate was significantly slowed by 13% of the control value. The conduction velocity within all compartments of the heart was depressed uniformly. The all-over-all prolongation of the HBE-intervals was 15%. Furthermore the results are in favour of a prolongation of the ERP of the atrium and the ERP of the AV node. The results can only partially explain the antiarrhythmic effect of the drugs. However, the data are important for assessing the possible side effects during antiarrhythmic treatment especially in patients with disease of the conduction system.

[Clinical value of His bundle electrography (author's transl)]

Methodical problems, indication and clinical implication of His bundle electrography are discussed. In 200 successive patients undergoing His bundle electrography and atrial stimulation the indication was as follows: Intraventricular conduction defects in 24%, A-V block in 21%, sick sinus syndrome in 20%, preexcitation in 17%, and complex arrhythmias in the remaining cases. In 38% of the patients did the HBE prove to be of help by providing information not available after analysis of the surface ECG. In 22% this technique contributed essentially to the management of these patients. In spite of dificiencies of our knowledge of the basic mechanisms, specific therapy, and prognosis of various arrhythmias His bundle electrography is clinically useful in selected patients. Therefore, this method has become a routinely used clinical tool.

[Diagnostic and prognostic value of endomyocardial biopsy in patients with congestive cardiomyopathy (author's transl)]rdiomyopathy(author

Endomyocardial biopsies were obtained from the right ventricle in 25 patients with the clinical diagnosis of congestive cardiomyopathy. The biopsies were subjected to virological and histological studies (light and electronmicroscopy) and the findings correlated with clinical data. Abnormal morphological findings were present in all patients. The presumed clinical diagnosis was confirmed in 19, the morphological changes not being consistent with the clinical diagnosis of CCM in six patients. Electronmicroscopy revealed cardiac storage disease in one patient and pathological changes secondary to previous myocarditis in the other five. Clinical follow-up studies of the five patients apparently confirmed the morphological results, because in no case was there clinical deterioration, three patients in fact being in a fairly normal cardiac state at present. Using a morphological scoring system, the 19 patients with morphologically confirmed diagnosis of CCM were subdivided into two groupds, those with four points or less (group I, n equal to 9), and those with five pints or more (group II, n equal to 10). During a mean follow-up period of nearly 12 months the first group had a low mortality rate (n equal to 2), while the other had a high one (n equal to 6). The occurrence of signs of degeneration and mitochondrial alterations, in particular, was associated with a poor clinical prognosis. This differentiation into two groupds could not be achieved by clinical means alone. Type B3 Coxsackie virus was isolated from one biopsy, but no patient had significant serological evidence of virological infection.

[Diagnostic problems in the sinus node syndrome]

The sick sinus syndrome includes numerous arrhythmias due to various functional disorders of the sinus node, the atria and the A-V junctional tissue. These disturbances of impulse formation and conduction involve many diagnostic problems. If clinical methods as ECG monitoring are of no help, provocative tests are indicated. The best indirect test of the sinus node activity is the measurement of the sinus node recovery time after overdrive suppression. In addition, the sinu-atrial conduction time, the conduction velocity within the right atrium, the A-V node and the His-Purkinje system can be measured. In patients with the sick sinus syndrome abnormalities of conduction in the specialized cardiac tissue are common in addition to sinus node dysfunction. The results of the provocative tests are important for drug therapy or pacemaker implantation.

[Atrioventricular conduction in the Lown-Ganong-Levine syndrome]

In 18 patients with LGL-syndrome His bundle electrography and atrial pacing were performed. In all cases the atrial conduction time was normal, the H-V interval within the lower limit (36 msec). The A-H interval was significantly shortened (58 msec). During rapid atrial pacing four different patterns of reaction could be distinguished: 1) A-H interval unchanged (1 case). 2) Sudden prolongation of the A-H interval at a critical rate (4 cases). 3) Continuous prolongation of the A-H time according to the driving frequency (9 cases). 4) Marked delay and block (4 cases). Verapamil had only little or no effect on the A-H interval in these patients. The results indicate, that only in a few cases with LGL-syndrome the shortened A-H time is due to a James bundle bypassing completely the A-V node.