Hans Schüller

Lund University, Lund, Skåne, Sweden

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Publications (15)58.86 Total impact

  • Carl J Höijer · Peter Höglund · Hans Schüller · Johan Brandt
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    ABSTRACT: Despite several decades of experience with atrial pacing, many centers do not apply this mode to any greater extent, mainly because of concerns for the development of future atrioventricular (AV) block or atrial fibrillation. Recent studies have emphasized possible negative effects of right ventricular stimulation, even when AV-synchrony is preserved, and have thus given rise to renewed interest in single chamber atrial pacing for sinus node disease. This study presents the results of up to 19 years' follow-up of 213 patients with sinus node disease treated with atrial pacing with respect to survival and causes of death, development of atrial fibrillation and AV block, and total mode survival. Patients were divided into two groups: with or without associated atrial tachyarrhythmias at the time of implant. Results are given for all patients and for the two groups separately. The mean follow-up time was 10.1 years. The survival of the entire group was lower after 10 years than that of an age and gender-matched general Swedish population. This was caused by patients with the brady-tachy syndrome (BT) having a significantly higher mortality rate than controls, whereas those with bradycardia only (B) had survival comparable to the general population. Permanent atrial fibrillation (AF) developed in 20% of patients and was significantly more common in patients with BT. The majority of patients with AF (78%) no longer needed any pacing, i.e., did not require ventricular stimulation due to slow ventricular rate. The annual incidence of high grade AV block was 1.8%. If patients with preexisting bundle branch block were excluded, the incidence was 1.6%. No fatal episode of AV block was seen. The overall mode survival at the end of follow-up was 75%, with 155 patients still with atrial pacemakers. Atrial pacing is a safe and reliable mode of pacing in patients with sinus node disease, even in the very long-term.
    Pacing and Clinical Electrophysiology 07/2007; 30(6):740-7. DOI:10.1111/j.1540-8159.2007.00744.x · 1.25 Impact Factor
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    Johan Brandt · Hans Schüller
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    ABSTRACT: Symptomatic sinus node disease is a common indication for permanent pacemaker implantation. Single-chamber ventricular (VVI) pacing, single-chamber atrial (AAI) stimulation, and dual-chamber (DDD or DDI) systems are used to a varying extent at different implanting centers. Hemodynamic and clinical studies relevant to the choice of pacing mode in these patients are reviewed. The data currently available strongly support the use of pacing systems providing atrial stimulation. The choice between single-chamber atrial or dual-chamber pacing can be based on the relative importance assigned to a number of factors: Hemodynamic aspects, the risk of ventricular lead problems, cost, and complexity aspects favor AAI pacing, whereas patients with a substantial risk of developing atrioventricular block should receive a DDD or DDI unit.
    Clinical Cardiology 10/1994; 17(9):495-8. DOI:10.1002/clc.4960170907 · 2.23 Impact Factor
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    ABSTRACT: This study was designed to analyze the incidence and determinants of complications and long-term survival in sinus node disease treated with atrial pacing. Knowledge of the natural history of sinus node disease treated with different pacing modes is imperfect, and controversy exists regarding the optimal pacemaker therapy. A consecutive series of 213 patients with sinus node disease initially treated with atrial pacing was studied for a median follow-up period of 60 months. The end points studied were permanent atrial fibrillation, high grade atrioventricular (AV) block, P wave undersensing, pacing mode change, reoperation and death. Several prognostic factors were evaluated statistically and the survival rate was compared with that of a matched general population. The incidence rate of permanent atrial fibrillation during follow-up was 7% (1.4%/year). The risk of this arrhythmia increased substantially with age greater than or equal to 70 years at pacemaker implantation. Only 2 of the 15 patients who developed permanent atrial fibrillation required ventricular pacing. High grade AV block occurred in 8.5% (1.8%/year) and its incidence was much greater in patients with complete bundle branch block or bifascicular block (35%) than in patients without such conduction disturbances (6%). A change to ventricular or dual-chamber stimulation was necessary in 14% of all patients, primarily because of early lead dislodgment or high grade AV block. Surgical intervention with maintenance of atrial pacing was required in 7% of patients. The survival rates of 97% at 1 year, 89% at 5 years and 72% at 10 years did not differ significantly from those of a matched general population. In sinus node disease, atrial pacing can be successfully applied during long-term follow-up. Patients with complete bundle branch or bifascicular block in addition to sinus node disease should initially receive a dual-chamber pacemaker, but routine application of dual-chamber stimulation does not appear to be warranted.
    Journal of the American College of Cardiology 10/1992; 20(3):633-9. DOI:10.1016/0735-1097(92)90018-I · 15.34 Impact Factor
  • Johan Brandt · Thomas Fahraeus · Tadashi Ogawa · HANS SCHÜLLER
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    ABSTRACT: Forty-four patients with sinus node disease and chronotropic incompetence but no evidence of AV conduction disturbances were treated with rate adaptive atrial (AAI,R) pacemakers. Medtronic Activitrax and Siemens Sensolog activity sensing single chamber pulse generators were used. Twenty-four patients (55%) had the bradycardia-tachycardia syndrome. The mean follow-up time is 20 +/- 14 months (range 1-48, median 17 months). All patients remain alive. Two patients were reoperated upon for lead problems without change of pacing mode. One patient developed symptomatic second-degree Wenckebach block during follow-up, and received a DDD,R system. Although 22 of the patients were treated with antiarrhythmic drugs postoperatively, no further cases of significant AV conduction disturbances were seen. During rapid atrial pacing, exercise-induced enhancement of AV conduction was a consistent finding, although less pronounced in patients treated with beta-blocking drugs. One patient developed permanent atrial fibrillation with an adequate ventricular rate. By systematic reprogramming procedures, QRS complex sensing through the atrial electrode could be demonstrated in 25 patients (23/28 with unipolar and 2/16 with bipolar leads). It could be counteracted effectively by pulse generator program selection in all cases. Forty-two of 44 patients (95%) remain in AAI,R pacing with normal function. Rate adaptive atrial pacing can be successfully applied in this patient group.
    Pacing and Clinical Electrophysiology 09/1991; 14(8):1258-64. DOI:10.1111/j.1540-8159.1991.tb02865.x · 1.25 Impact Factor
  • H Schüller · J Brandt
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    ABSTRACT: The pacemaker syndrome refers to symptoms and signs in the pacemaker patient caused by inadequate timing of atrial and ventricular contractions. The lack of normal atrioventricular synchrony may result in decreased cardiac output and venous "cannon A waves." A sudden increase in atrial pressure at the onset of asynchrony may elicit a systemic hypotensive reflex response. A wide range of symptoms can be observed. The pacemaker syndrome is encountered in a significant number of patients with ventricular (VVI) pacemakers, mostly when 1:1 retrograde ventriculoatrial conduction is present. The risk of occurrence of the pacemaker syndrome is minimized if pacemaker systems are used which restore or maintain the normal atrioventricular contraction sequence. Hence, in sinus node disease, atrial stimulation with or without ventricular stimulation should be employed, while in high-grade atrioventricular block dual-chamber pacing is recommended. The pacemaker syndrome is not restricted to the VVI stimulation mode. It can be seen, though rarely, in atrial and dual-chamber pacing, and an awareness of these new causes is necessary. An established pacemaker syndrome can often be counteracted by adjusting the pulse generator function.
    Clinical Cardiology 05/1991; 14(4):336-40. · 2.23 Impact Factor
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    ABSTRACT: The atrial and ventricular pacing threshold development during the first postoperative year was studied in a group of patients receiving DDD pacemakers. Identical carbon-tip endocardial leads were implanted in atrium and ventricle. Atrial and ventricular voltage stimulation thresholds were measured at implantation, and noninvasively at 1 and 12 months thereafter. The atrial amplifier sensitivity required for adequate P wave sensing during follow-up was also determined. The possible influence of a number of factors upon atrial and ventricular threshold evolution was statistically assessed. The threshold data were complete in 57 patients (mean age +/- SD, 65.2 +/- 12.4 years). Thirteen patients had a diagnosis of sinus node disease, whereas 44 had not. Patient age and diagnosis did not significantly influence atrial or ventricular stimulation threshold development. Atrial sensing thresholds were not related to atrial stimulation thresholds during follow-up. Atrial pacing thresholds were higher than ventricular thresholds at pacemaker implantation (P less than 0.00005), but the postoperative threshold rise and thresholds at 1 and 12 months postoperatively did not differ significantly between the atrium and ventricle. The ratio of chronic to acute stimulation thresholds was higher on the ventricular than on the atrial level (0.001 greater than P greater than 0.0005). The chronic atrial threshold showed a logarithmic relation to the threshold at implantation (P = 0.0006); postoperative threshold rise was not a significant determinant of the chronic atrial threshold (P = NS). On the ventricular level, the reverse was seen: The chronic threshold was related to the postoperative threshold rise (P = 0.0015, logarithmic relation), but not to the implantation threshold (P = NS).(ABSTRACT TRUNCATED AT 250 WORDS)
    Pacing and Clinical Electrophysiology 08/1990; 13(7):859-66. DOI:10.1111/j.1540-8159.1990.tb02122.x · 1.25 Impact Factor
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    ABSTRACT: Data are reviewed from 88 patients who received double, passive-fixation unipolar endocardial leads for DDD pacemaker treatment. Identical electrodes were used in the right atrium and the right ventricle. Intra-atrial P wave amplitudes, intraventricular QRS complex amplitudes, and atrial and ventricular pacing thresholds were determined at implantation. The intra-atrial P wave amplitudes were not significantly correlated to the intraventricular QRS complex amplitudes. No significant correlation was found between the atrial stimulation thresholds and the ventricular pacing thresholds. The intra-atrial P wave amplitude showed a significant inverse and logarithmic correlation with patient age (P = 0.007). Furthermore, patients with sinus node disease had significantly lower intra-atrial P wave amplitudes (P = 0.04) than patients without this abnormality. The acute atrial and ventricular pacing thresholds and the intraventricular QRS complex amplitude were not correlated to patient age or presence of sinus node disease. Patients requiring higher atrial amplifier sensitivity settings during follow-up were significantly older (P less than 0.05) than those in whom lower atrial sensitivities were sufficient. A postoperative attenuation of the atrial electrogram was detectable by sensitivity programming procedures in 29 of the patients (35%). This phenomenon did not significantly relate to patient age or presence of sinus node disease. No case of permanent atrial undersensing occurred. It is suggested that the lower intra-atrial P wave amplitudes in older patients and patients with sinus node disease reflect degenerative changes in the atrial myocardium. The statistical relations found appear to motivate special attention to atrial sensing in these patient groups.
    Pacing and Clinical Electrophysiology 05/1990; 13(4):417-24. DOI:10.1111/j.1540-8159.1990.tb02056.x · 1.25 Impact Factor
  • Johan Brandt · Thomas Fahraeus · H Schüller
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    ABSTRACT: To study the prevalence and significance of far-field QRS complex sensing via unipolar atrial electrodes, we attempted to provoke this phenomenon postoperatively in 119 patients with DDD pacemakers. It occurred in 42 patients (35%), with different types of atrial electrodes. In 27 cases with documented far-field QRS complex sensing, selection of an adequate atrial amplifier sensitivity eliminated the problem; in the remaining 15 cases, other program adjustments were necessary. In all patients DDD pacing could be maintained, and no reoperations were required. In a retrospective analysis of a subgroup of 26 patients, all having received endocardial unipolar carbon tip electrodes in the right atrial appendage, the possibility of predicting subsequent far-field QRS complex sensing was studied. The occurrence thereof was not significantly related to patient age or sex, indication for pacing, or routinely obtained electrophysiological measurements. Potential far-field QRS complex sensing via the atrial electrode is significantly common in patients with DDD pacemakers. Patient characteristics and intraoperatively measured intraatrial signal amplitudes are not useful in predicting the postoperative occurrence of the phenomenon. As a rule, it can be handled effectively by pulse generator reprogramming.
    Pacing and Clinical Electrophysiology 12/1988; 11(11 Pt 1):1540-4. DOI:10.1111/j.1540-8159.1988.tb06271.x · 1.25 Impact Factor
  • J Brandt · T Fåhraeus · H Schüller
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    ABSTRACT: Unintended sensing of QRS complexes via atrial pacemaker leads may cause disorders of pacemaker function in AAI, VDD and DDD pacing. The consequences of this phenomenon depend upon the pacing mode and the timing of the inappropriate sensing as related to the technical characteristics of the pulse generator. With AAI pacemakers, "inappropriate pacemaker bradycardia" may be seen or P-wave undersensing may be simulated. With VDD and DDD systems a special kind of pacemaker mediated tachycardia or apparent P-wave undersensing may result. With knowledge of the underlying mechanisms, differential diagnosis is possible. The countermeasures available are discussed.
    Pacing and Clinical Electrophysiology 11/1988; 11(10):1432-8. · 1.25 Impact Factor
  • JOHAN BRANDT · THOMAS FÅHRAEUS · HANS SCHÜLLER
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    ABSTRACT: Unintended sensing of QRS complexes via atrial pacemaker leads may cause disorders of pacemaker function in AAI, VDD and DDD pacing. The consequences of this phenomenon depend upon the pacing mode and the timing of the inappropriate sensing as related to the technical characteristics of the pulse generator. With AAI pacemakers, “inappropriate pacemaker bradycardia” may be seen or P-wave undersensing may be simulated. With VDD and DDD systems a special kind of pacemaker mediated tachycardia or apparent P-wave undersensing may result. With knowledge of the underlying mechanisms, differential diagnosis is possible. The countermeasures available are discussed.
    Pacing and Clinical Electrophysiology 09/1988; 11(10):1432 - 1438. DOI:10.1111/j.1540-8159.1988.tb04992.x · 1.25 Impact Factor
  • Y S Jin · Nils Mandahl · Sverre Heim · Hans Schüller · Felix Mitelman
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    ABSTRACT: We have cytogenetically analyzed three primary adenocarcinomas of the lung. All tumors had chromosome numbers in the triploid region. The multiple structural aberrations included rearrangements of 3p, in two cases affecting the segment 3p14-23, where deletions are characteristically found in small cell lung carcinomas. Isochromosomes for 8q were present in two tumors and i(9q) in one tumor. In the few previously reported cytogenetic analyses of pulmonary adenocarcinomas, all of which examined metastases or cell lines, i(8q) was found in one case and i(9q) in two cases. These isochromosomes, therefore, represent previously unrecognized nonrandom changes in adenocarcinomas of the lung, and might constitute primary aberrations in this tumor type.
    Cancer Genetics and Cytogenetics 08/1988; 33(1):11-7. DOI:10.1016/0165-4608(88)90043-X · 1.93 Impact Factor
  • Mȧrten Rosenqvist · Johan Brandt · Hans Schüller
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    ABSTRACT: In a previous retrospective treatment-comparison study of 168 patients with sinus node disease, we found a significantly higher incidence of permanent atrial fibrillation and congestive heart failure in patients treated with ventricular (VVI) pacing compared to atrial (AAI) pacing, after an average follow-up period of 2 years. To determine whether these differences persisted and whether AAI pacing resulted in a lower mortality rate than VVI pacing during long-term follow-up, the treatment groups were restudied after an average of 4 years of pacemaker treatment. The incidence of permanent atrial fibrillation was still significantly higher (p less than 0.0005) in the VVI group than in the AAI group after the additional 2 years (VVI = 47%, an increase from 29%; AAI = 6.7%, an increase from 3.4%). Congestive heart failure occurred significantly more often in the VVI group than in the AAI group (37% vs 15%, p less than 0.005). Analysis of survival data showed a higher overall mortality rate in the VVI group (23% vs 8%, p less than 0.05). The development of high-degree atrioventricular block in the AAI group remained low (total 4.5%). Thus, in sinus node disease, the advantages of AAI over VVI pacing persist during long-term follow-up. The differences in cardiovascular morbidity between the groups tend to increase with time and appear to result in a lower mortality rate among patients treated with AAI pacing.
    American Heart Journal 08/1988; 116(1 Pt 1):16-22. DOI:10.1016/0002-8703(88)90244-X · 4.56 Impact Factor
  • Mȧrten Rosenqvist · Johan Brandt · Hans Schüller
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    ABSTRACT: Treatment with conventional ventricular pacing does not seem to influence the natural course in patients with sinus node disease (SND). In the present study the natural course of SND was compared in patients treated with ventricular (VVI) and those treated with atrial (AAI) pacing. The study population comprised 168 patients, 89 with atrial and 79 with ventricular pacing. The two groups were comparable with respect to clinical characteristics, degree of severity of SND, and length of follow-up period (average 2 years). Development of chronic atrial fibrillation and congestive heart failure was significantly more common in patients with ventricular than in those with atrial pacing (30% vs 4%, p less than 0.001; 23% vs 7%, p less than 0.01). Second-degree atrioventricular block developed in 4% of the atrially paced patients. Thus, atrial pacing is apparently superior to ventricular pacing in patients with SND.
    American Heart Journal 03/1986; 111(2):292-7. DOI:10.1016/0002-8703(86)90142-0 · 4.56 Impact Factor
  • J Brandt · O Pahlm · H Schüller
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    ABSTRACT: The interpretation of the ECG of a dual chamber pacemaker necessitates the identification of atrial activity. This is a prerequisite for the evaluation of pacemaker function and for the correct adjustment of programmable pulse generators. The assessment of atrial capture in standard 12-lead ECGs is, however, sometimes rather difficult. Esophageal ECG recording by means of a reusable unipolar electrode, inserted transnasally, and connected to a standard ECG recorder, is a simple, rapid and inexpensive method for the reliable identification of P-waves. Clinical examples are presented to illustrate the value of this technique in determining atrial capture and as a tool for the differential diagnosis of pacemaker-involved tachycardias. The use of esophageal ECG recording in the clinical follow-up of patients with dual chamber pacemakers is recommended.
    European Heart Journal 05/1985; 6(4):342-8. · 14.72 Impact Factor
  • Johan Brandt · Hans Schüller
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    ABSTRACT: The influence of age of the adult pacemaker patient upon postoperative threshold rise and chronic stimulation threshold was investigated by means of noninvasive threshold measurements in a group of 47 patients (aged 50 to 93 years), all provided with porous endocardial ventricular electrodes (Cardiac Pacemakers, Inc.) and Siemens-Elema Vario pulse generators. The voltage threshold recorded at implantation showed no age dependence; however, the threshold rise within 1 month after implantation, maximal recorded threshold, as well as the chronic threshold were inversely related to age--i.e., in older patients lower values were obtained. These results probably reflect a lesser local tissue reaction at the site of the electrode tip in the elderly. In the individual patient no relation could be found between stimulation threshold at implantation and maximal or chronic threshold.
    American Heart Journal 05/1985; 109(4):816-20. DOI:10.1016/0002-8703(85)90644-1 · 4.56 Impact Factor