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Biomedical subjects

J Brunn

Publications and source records attributed to J Brunn.

At least 19 recordsLinked to original sources
PubMed2001

Defibrillation efficacy comparing a subcutaneous array electrode versus an "active can" implantable cardioverter defibrillator and a subcutaneous array electrode in addition to an "active can" implantable cardioverter defibrillator: results from active can versus array trials I and II.

INTRODUCTION: Placement of implantable cardioverter defibrillators (ICDs) has been simplified by using the shell of a pectorally implanted ICD as a defibrillation electrode in combination with an endocardial right ventricular defibrillation lead. However, a sufficiently low defibrillation threshold (DFT) cannot be obtained in a few patients. Therefore, alternative approaches were systematically tested in the Active Can versus Array Trial (ACAT). METHODS AND RESULTS: In the first of two prospective randomized studies, the DFT of a subcutaneous left dorsolateral array anode introduced from a pectoral incision was compared to that of a standard active can anode in 68 patients. Intraoperatively, the DFT was determined twice in each patient using either the active can or, in patients with a subcutaneous array lead, once with all three fingers and once omitting the middle finger of the array. The second prospective randomized study included 40 patients. DFT also was determined twice in each patient using an active can in a left pectoral position as anode alone and combined with a left dorsolateral array electrode with two fingers. In ACAT I, stored energy at DFT decreased from 13.1+/-7.7 J (active can) to 9.6+/-6.1 J (three-finger array lead) (P = 0.04), impedance decreased from 53+/-8 ohms to 40+/-6 ohms (P < 0.0001). Omitting the middle finger of the array lead, stored energy at DFT increased by 0.9 J (P = 0.47) and impedance by 2 ohm (P < 0.0001). In ACAT II, DFT and impedance using an active can device were significantly lower when a two-finger array lead was added that decreased stored energy at DFT from 10.1+/-5.2 J to 6.9+/-3.9 J (P = 0.001) and impedance from 56+/-5 1 to 42+/-5 l (P < 0.0001). CONCLUSION: In combination with a right ventricular defibrillation electrode, a left pectoral subcutaneous array lead improves defibrillation efficacy if used instead of, or in addition to, a left pectoral active can ICD device. Implantation of the array lead can be simplified by using two instead of three fingers, without a significant loss of defibrillation efficacy.

Adult↗
PubMed2001

[Multi-slice spiral CT of the coronary arteries: clear vascular imaging using standard software].

OBJECTIVE: To visualize the coronary arteries with a clear view and over a long distance by using data sets from contrast-enhanced computed tomography of the heart. MATERIAL AND METHODS: Image data of 151 patients suffering from coronary artery disease were calculated by means of retrospective triggering at four different diastolic delay times in contrast-enhanced CT. The large coronary segments were subsequently reconstructed in two planes with multiplanar volume reconstruction (MPVR)--a non-dedicated postprocessing software. RESULTS: On the pre-condition that data sets were acquired at sinus rhythm and at a heart beat rate lower than 65/min coronary arteries could be depicted over a long distance in single or double angulated reconstruction planes with the help of multiplanar volume reconstruction (MPVR). Time consumption for image reconstruction was reasonable. Additionally to the anatomy of the coronary arteries in two different planes, typical CT findings in occluding coronary artery disease are presented. CONCLUSION: Multiplanar volume reconstruction (MPVR) implemented on most workstations is a powerful and ideal postprocessing tool in reconstructing coronary arteries from contrast-enhanced CT data sets.

Coronary Angiography↗
PubMed2000

Clusters of ventricular tachycardias signify impaired survival in patients with idiopathic dilated cardiomyopathy and implantable cardioverter defibrillators.

OBJECTIVES: This retrospective study was undertaken to provide data on occurrence, significance and therapy of ventricular tachyarrhythmia (VT) clusters (VTCs) in patients with dilated cardiomyopathy (DCM) and implantable cardioverter defibrillators (ICDs). BACKGROUND: Data on the clinical significance of VTCs are lacking in patients with DCM and ICDs. METHODS: Baseline characteristics of 106 consecutive patients with DCM and ICDs were prospectively collected, and chart reviews and episode data retrospectively analyzed. A VTC was defined as > or =3 sustained VTs/24 h. RESULTS: During a mean follow-up of 33+/-23 months, 73 patients (68.9%) had recurrent VT or ventricular fibrillation (VF), 43 patients (40.6%) suffered only single VTs and 30 patients (28.3%) experienced 52 clusters of VTs. Actuarial survival free of VT or VF was 44.6%, 33.0% and 26.5%, and survival free of VTC was 77.3%, 72.2% and 67.1% after one, two and three years, respectively. Independent predictors of VT clusters were heart failure before ICD implantation (p = 0.033), presenting monomorphic VT (p = 0.044), EF <0.40 (p = 0.014) and inducible mVT, especially with right bundle branch block and superior axis configuration (p<0.001). Survival free of recurrent VTCs was 50.8%, 38.1% and 19.0% after one, two and three years, respectively. Once a VTC had occurred, only 56.7%, 46.4%, 30.9% and 15.5% of patients survived and were not transplanted after one, two, three and four years, respectively. Survival was even more reduced if a VTC was associated with cardiac decompensation: 65.6% and 21.9% after one and two years, respectively. CONCLUSIONS: Despite antiarrhythmic intervention, clusters of VTs occur and recur frequently in patients with DCM. They signify impaired survival, especially if they are associated with cardiac decompensation, and may be a harbinger of progressive myocardial deterioration rather than a primarily arrhythmic problem. The benefit of ICD therapy may therefore be low in these patients.

Aged↗
PubMed2000

Is there a need for routine testing of ICD defibrillation capacity? Results from more than 1000 studies.

AIMS: Benefits and complications of postoperative implantable cardioverter-defibrillator tests are controversial matters. This study sought to assess the necessity of defibrillation function tests after implantation. METHODS AND RESULTS: We retrospectively analysed 1007 implantable cardioverter-defibrillator tests in 587 systems and 556 patients. Nine hundred and thirty implantable cardioverter-defibrillator tests (89.4%) were routinely performed. Seventy-one tests (7%) were performed after a change in the antiarrhythmic drug regimen and six tests (0.60%) because of a suspected dysfunction of the implantable cardioverter-defibrillator. During routine tests, four systems (0.4%) failed to defibrillate the patient. However, in all but one test, abnormalities of the system had been observed before the test. After the addition of antiarrhythmic drugs, two of 71 implantable cardioverter-defibrillator systems (2.8%) failed to defibrillate the patient. One of six systems tested due to a suspected dysfunction failed to defibrillate the patient. During 16 tests (1.6%), complications occurred. CONCLUSIONS: Our experience demonstrates that postoperative tests of the defibrillation function of implantable cardioverter-defibrillators rarely reveal dysfunctions. As testing is unpleasant for the patient and not free of complications, tests might be restricted to those patients in whom a dysfunction is suspected and to those patients in whom class I or class III antiarrhythmic drugs have been added to the antiarrhythmic drug regimen.

Adolescent↗
PubMed1999

Efficacy and safety of the initial use of stability and onset criteria in implantable cardioverter defibrillators.

INTRODUCTION: Inappropriate therapies are the most frequent adverse event in patients with implantable cardioverter defibrillators (ICDs). Most ICDs offer a stability criterion to discriminate ventricular tachycardia (VT) from atrial fibrillation and an onset criterion to discriminate VT from sinus tachycardia. The efficacy and safety of these criteria, if used immediately after implantation, is unknown. METHODS AND RESULTS: In a case control study, 87 patients in whom stability and onset criteria had been activated immediately after ICD implantation were matched to 87 patients in whom these criteria had not been activated. The groups were matched for known predictors of inappropriate therapies. With stability and onset criteria off, 24 patients (28%) received inappropriate therapies due to atrial fibrillation (n = 14) or sinus tachycardia (n = 11); with stability and onset on, only 11 patients (13%) were treated by the ICD due to atrial fibrillation (n = 5) or sinus tachycardia (n = 7) (log rank: P = 0.029). Five patients suffered inappropriate therapies despite the fact that onset (n = 4) or stability (n = 1) criteria were not fulfilled once tachycardias continued for a prespecified duration. Only one patient experienced a failure to detect VT due to the onset criterion; none because of stability. CONCLUSION: The immediate use of stability and onset criteria after ICD implantation reduces inappropriate therapies due to atrial fibrillation and sinus tachycardia. Because of the potential for underdetection of VT, this approach should be limited to tachycardia rates hemodynamically tolerated by the patient.

Atrial Fibrillation↗
PubMed1998

Potential benefit from implantable cardioverter-defibrillator therapy in patients with and without heart failure.

BACKGROUND: Whether patients with heart failure derive a benefit from therapy with implantable cardioverter-defibrillators (ICDs) has been questioned. The purpose of this study was to investigate whether New York Heart Association (NYHA) functional class had an impact on the potential benefit from ICD therapy as assessed from data stored in the memory of ICDs. METHODS AND RESULTS: Between 1989 and 1996, 603 patients (77% men; 59% with coronary artery disease and 16% with dilated cardiomyopathy; age, 57+/-13 years; ejection fraction, 44+/-18%) were treated with an ICD with extended memory function (storage of electrograms and/or RR intervals from treated episodes) in combination with endocardial lead systems. The stages of heart failure (NYHA functional class I through III) at implantation were correlated with overall mortality and the recurrence of fast ventricular tachyarrhythmias (>240 bpm) during follow-up. The potential benefit of the device was estimated as the difference between overall mortality and the hypothetical death rate had the device not been implanted. The latter was based on the recurrence of fast and, without termination by the devices, presumably fatal ventricular tachyarrhythmias. In the overall group, a significant difference between hypothetical death rate and overall mortality was observed (13.9%, 23.5%, and 26.6% at 1, 3, and 5 years, respectively) that suggested a benefit from ICD implantation. In patients in NYHA class I, the estimated benefit, which increased over time, was 15.2%, 29.2%, and 35.6% after 1, 3, and 5 years, respectively. In patients in NYHA class II or III, the estimated benefit increased until the third year (21.8% and 21.9%, respectively) and then remained constant until the fifth year (22.9% and 23.8%, respectively). Even those patients in NYHA class III with a history of decompensated heart failure benefited from ICD implantation. CONCLUSIONS: Analysis of stored ECG data suggests that in patients with a history of ventricular tachycardia or ventricular fibrillation, ICD therapy may lead to a prolongation of life in NYHA classes I through III. The initial benefit is greatest in patients in NYHA class II and class III, but the estimated benefit might persist longest for patients in NYHA class I.

Adolescent↗
PubMed1998

Syncope in patients with an implantable cardioverter-defibrillator: incidence, prediction and implications for driving restrictions.

OBJECTIVES: This retrospective study was undertaken to provide information on occurrence, risk prediction and prevention of syncope in patients with an implantable cardioverter-defibrillator (ICD). BACKGROUND: ICDs effectively terminate ventricular tachycardia and fibrillation (VT/VF). Incapacitating symptoms, such as syncope, may still occur. METHODS: We performed a retrospective analysis of data from 421 patients (clinical history, outpatient chart reviews and episode data) with mean (+/-SD) follow-up of 26 +/- 18 months. RESULTS: Of 421 patients, 229 (54.4%) had recurrent VT/VF, and 62 (14.7%) had syncope. The actuarial survival rate free of VT/VF was 58%, 45% and 37% and that for survival free of syncope was 90%, 85% and 81% at 12, 24 and 36 months after implantation, respectively. Once VT/VF had occurred, 76%, 68% and 62% of patients remained free of syncope during the following 12, 24 and 36 months, and 68%, 64% and 56% remained free of second syncope 12, 24 and 36 months after first syncope, respectively. In cases of syncope, the mean cycle length (CL) of VT was 251 +/- 56 ms. A low baseline left ventricular ejection fraction (LVEF), induction of fast VT (CL <300 ms) during programmed ventricular stimulation and chronic atrial fibrillation (AF) were associated with an increased risk of syncope. If the LVEF was >40%, fast VT had not been induced, and patients had no chronic AF; 96%, 92% and 92% of patients remained free of syncope after 12, 24 and 36 months, respectively. Once patients had a VT recurrence, syncope during the first VT and a high VT rate were the strongest risk predictors of future syncope. CONCLUSIONS: Identification of patients with an ICD with a low and high risk of syncope seems to be feasible and might help as a guide to driving restrictions in such patients.

Adolescent↗
PubMed1997

[Results of testing defibrillator function of implanted cardioverter/defibrillators].

Postoperative tests of implantable cardioverter defibrillators (ICDs) are routinely performed to ensure appropriate defibrillation by the device. However, efficacy and complications of this procedure are unknown. To scrutinize the currently accepted indications to test the defibrillation function of the ICD we retrospectively analyzed 844 ICD-tests in 439 ICD-systems and 409 patients. 755 ICD-tests (89.4%) were routinely performed (57% before discharge and 43% during follow-up); 58 tests (6.9%) were performed after a change of the antiarrhythmic drug regimen, 24 tests (2.9%) after a revision of a part of the ICD-system, and seven tests (0.8%) because of a suspected dysfunction of the ICD. During routine-tests six ICD-systems (0.8%) failed to defibrillate the patient. However, in all but one test abnormalities of the ICD-system had been observed before the test. After addition of antiarrhythmic drugs, three of 58 ICD-systems (5.2%) failed to defibrillate the patient during the test (amiodarone: n = 2, flecainide: n = 1). Four of seven ICD-systems (57%) tested due to a suspected dysfunction failed to defibrillate the patient. After revisions of parts of the ICD-systems, ICD-tests never revealed a failure of defibrillation. During 16 ICD-tests (1.9%) complications occurred. The most frequent complications was inappropriate shocks (n = 10; 1.2%), the most severe one (transient) neurologic symptoms (n = 4; 0.48%). Our experience demonstrates that postoperative tests of the defibrillation function of ICDs rarely reveal ICD-dysfunction. As testing is unpleasant for the patient and not free of complications, tests might be restricted to those patients in whom an ICD-dysfunction is suspected (based on clinical presentation, results of chest-x-ray, testing of sensing signal and stimulation threshold) or class I or class III antiarrhythmic drugs have been added to the antiarrhythmic drug regimen.

Adolescent↗
PubMed1996

Cardiac output is not affected during intraoperative testing of the automatic implantable cardioverter defibrillator.

INTRODUCTION: Perioperative mortality of patients undergoing implantation of automatic implantable cardioverter defibrillators (ICDs) has been reduced dramatically following the availability of transvenous-subcutaneous defibrillation leads. However, patients with severely reduced left ventricular function show a substantial rate of nonsudden cardiac mortality within the first year. Whether repeated intraoperative inductions of ventricular tachycardia/fibrillation (VT/VF) during implantation lead to hemodynamic deterioration and thus might contribute to development of end-stage heart failure in these patients is unknown. The purpose of the present study was to determine cardiac output and hemodynamic performance during transvenous-subcutaneous ICD implantation in patients with severe left ventricular dysfunction. METHODS AND RESULTS: In 11 patients with a left ventricular ejection fraction (EF) < or = 0.35, cardiac output was measured automatically with a combined continuous cardiac output/mixed venous oxygen saturation pulmonary artery catheter system. ICD implantation was performed during standardized general anesthesia. In the 11 patients (EF = 27 +/- 2% [mean +/- SEM]) a total of 95 episodes of VT/VF followed by defibrillation were induced (episodes per patient = 9 +/- 1; range 6 to 11). Cardiac index was 2.2 +/- 0.2 L.min-1.m-2 after induction of anesthesia (before start of surgery), and 1.9 +/- 0.1 L.min-1.m-2 immediately before first induction of VT/VF. After the last episode of VT/VF, cardiac index was 2.1 +/- 0.2 L.min-1.m-2. Cardiac index measured 1, 2, and 3 minutes after induction of VT/VF was not significantly different when compared to the preinduction value during any episode of VT/VF induction. Similarly, stroke volume index was 39 +/- 5 mL.m-2 immediately before first induction of VT/VF and 36 +/- 3 mL.m-2 after the last episode of VT/VF (NS). At the end of surgery, hemodynamic parameters did not exhibit any significant difference when compared to the data obtained before start of ICD implantation and testing. CONCLUSION: Extensive defibrillation tests during transvenous-subcutaneous ICD implantation in patients with severe left ventricular dysfunction are not associated with acute deterioration of cardiac performance.

Cardiac Output↗
PubMed1996

[Inadequate therapies with implantable cardioverter-defibrillators--incidence, etiology, predictive factors and preventive strategies].

Patients with implantable cardioverter defibrillators (ICD) often suffer inappropriate ICD-therapies. The incidence, causes and risk factors of ICD-therapies for a rhythm other than ventricular tachyarrhythmias (VT) were determined retrospectively in 462 consecutive patients (pts). Inappropriate ICD-therapies were identified based on stored R-R intervals and/or electrograms. Eighty-two pts (18%) had inappropriate ICD-therapies. Actuarial rates for inappropriate ICD-therapies were 13%, 20%, 24% and 29% at 1, 2, 3 and 4 years after ICD-implantation, respectively. Atrial fibrillation with rapid ventricular response was the most common cause (34 pts, 39%). In 26 pts (30%), sinus tachycardia triggered inappropriate ICD-therapies, in 21 pts (24%) overseeing, mostly due to fractures and insulation failures of the leads, in three pts atrial flutter, in two pts non-sustained VT, in one pt supra-ventricular tachycardia and in another pt T-wave double sensing caused inappropriate ICD-therapies. In order to prevent recurrences of inappropriate ICD-therapies due to atrial fibrillation or sinus tachycardia, a rate stability (n = 19) or onset (n = 15) criterion was programmed, 41 pts additionally received beta-blocking agents and/or digoxin. In pts with overseeing an operative revision of lead system was performed. During further follow-up (15 +/- 13 months), 15 pts had recurrences of inappropriate ICD-therapies (eight pts due to atrial fibrillation, three due to sinus tachycardia and four due to overseeing). On multivariate analysis (Cox regression), history of atrial fibrillation, maximum heart rate during exercise and low cut-off rate for VT-detection were predictors of inappropriate ICD-therapies. Thus, inappropriate ICD-therapies are frequent, especially in the first year after implantation. Additional detection criteria, beta-blocking agents and/or digoxin prevent recurrences in most patients. In patients with a history of atrial fibrillation, high heart rate during exercise or a low cut-off rate for VT-detection, activation of additional detection criteria should be considered directly after ICD-implantation.

Adult↗
PubMed1995

Radiofrequency catheter ablation of sustained ventricular tachycardia in idiopathic dilated cardiomyopathy.

BACKGROUND: The feasibility of radiofrequency (RF) catheter ablation for the treatment of sustained ventricular tachycardia (VT) in patients with coronary artery disease and remote myocardial infarction has recently been demonstrated. At present, therapeutic options for VT in patients with idiopathic dilated cardiomyopathy (DCM) include antiarrhythmic drugs and implantable cardioverter/defibrillators (ICD). The purpose of the present study was to investigate the feasibility of RF catheter ablation in patients with idiopathic DCM who could not be adequately treated by conventional treatment modalities because of incessant or frequent, recurrent VT. METHODS AND RESULTS: RF current application for ablation of 9 VTs (mean cycle length, 402 +/- 78 ms) was attempted in 8 patients with idiopathic DCM (4 men, 4 women; mean age, 54 +/- 6 years; mean left ventricular ejection fraction, 30 +/- 9%). Inclusion criteria for ablation were incessant VT (n = 4) or frequent, recurrent VT reproducibly inducible with programmed electrical stimulation (n = 5). Three patients had suffered aborted sudden cardiac death, and 2 had experienced syncope. Two patients were artificially ventilated and catecholamine dependent for hemodynamic reasons at the time of attempted ablation. Potential target sites for RF current application were identified by detailed endocardial mapping during sinus rhythm, activation and entrainment mapping during VT, and pace mapping. After 7 +/- 5 RF pulses (range, 2 to 18 pulses; median, 6 pulses) applied with 32 +/- 7 W for 39 +/- 9 seconds, 6 of the 9 target VTs (67%) were rendered noninducible (4 of 4 incessant VTs and 2 of 5 chronic recurrent VTs). In 6 patients, VTs with ECG morphologies other than the target VTs were inducible after RF catheter ablation. Seven patients were on antiarrhythmic drugs during the ablation procedure and during the follow-up period of 8 +/- 5 months (range, 2 to 17 months). One patient received an ICD before RF ablation, 4 patients after RF ablation, and 1 patient after ablation of an incessant VT and before attempted ablation of frequent, recurrent VTs. One patient underwent heart transplantation 5 months after ablation in end-stage heart failure. There were no acute complications during the mapping and ablation procedure. During the follow-up period, 1 patient had been resuscitated from ventricular fibrillation 6 weeks after ablation and finally died of congestive heart failure 2 weeks later. No further episodes of incessant VT occurred in the patients who had undergone RF current application for ablation of incessant VT. A complete prevention of VT could be achieved in 2 of 8 patients, whereas in 5 patients, VT episodes were stored in the ICD devices during follow-up. CONCLUSIONS: The results of the present study indicate that RF current application for ablation of VT in a select group of patients with idiopathic DCM is feasible. The efficacy of RF ablation may be high in patients presenting with incessant VT, whereas the success rate seems to be only moderate in patients with chronic recurrent VT. In all patients, additional treatment options, including antiarrhythmic drugs, ICDs, and/or heart transplantation, were applied after RF ablation, indicating that RF ablation for this indication may be an adjunctive and not a curative treatment option.

Anti-Arrhythmia Agents↗
PubMed1993

[Torsade de pointes].

Torsade de pointes (TDP) is a polymorphic ventricular tachycardia with a particular electrocardiographic pattern of continuously changing ("twisting") morphology of the QRS complex occurring in the setting of delayed myocardial repolarization (i.e., prolongation of the QT interval). TDP may develop in the setting of an idiopathic disorder (Jervell/Lange-Nielsen syndrome, Romano-Ward syndrome, sporadic long QT syndrome) or may be induced by pharmacologic agents which prolong the QT interval, as well as by other clinical circumstances under which repolarization is delayed (e.g., hypokalemia, hypomagnesemia, bradycardia) (acquired long QT syndrome). Since the treatment of TDP strongly differs from that of conventional ventricular tachycardia, correct diagnosis is critical as it guides the treating physician in selecting the appropriate mode of therapy. In this paper mainly the electrocardiographic criteria presently used for the correct identification of this unusual form of ventricular arrhythmia are presented. Additionally, the potential mechanisms and therapeutic modalities of TDP are discussed.

Anti-Arrhythmia Agents↗
PubMed1993

[Diagnostic and therapeutic problems in idiopathic prolonged QT syndrome. A case report].

The case of a 36-year-old woman with suspected idiopathic long QT syndrome is reported. Diagnosis was made late after syncopal attacks and several episodes of resuscitation had occurred. Although therapy with a beta-blocking agent was initiated and a cardioverter/defibrillator was implanted, the patient died, due to a hydrocephalus internus resulting in cerebral damage. Diagnostic and therapeutic problems in idiopathic long QT syndrome are discussed.

Adult↗
PubMed1981

[Volumetric analysis of thyroid lobes by real-time ultrasound (author's transl)].

Thyroid volume as measured by real-time ultrasound in cadavers was compared with direct measurements obtained by submersion. Length X width X thickness of the thyroid lobe multiplied by factor pi/6, correspond to a rotation ellipsoid, while the best calculated volume of the lobe is obtained by multiplying with the optimised correction factor f = 0.479. The correctness of this calculation is, by definition, 100%; average error of the method is 16%. The measurements are easy to do and require no additional equipment for planimetry or calculations. Volumetric analysis of the thyroid gland is especially necessary in assessing results of treatment and for measuring dosage in connection with radioiodine therapy.

Goiter↗
PubMed1980

[Diagnosis of renal cysts (author's transl)].

Renal cysts were demonstrated in 48 out of 1000 non-selected patients investigated with sonography. Large cysts (mean diameter 4.8 cm) were also shown by urography. Smaller cysts (mean diameter 2.5 cm) could be diagnosed only by sonography. This method enabled establishment of the diagnosis in 3 out of 5 patients in whom there was radiographic suspicion of tumours. Ultrasound may also be used in the patient with renal failure. Powerful mobile equipment permits investigation at the bedside of the severely ill patient. Demonstration or exclusion of space occupying renal changes should make use of ultrasound as a primary diagnostic tool.

Diagnosis, Differential↗
PubMed1980

[Ultrasound cystometry for estimating residual urine (author's transl)].

The volume of urine in the bladder can be sufficiently accurately calculated in adults by ultrasound measurement of width, height and depth of the bladder and multiplication of these results by 0.57. The method is time saving, non-stressful, easy to learn and can be performed with any ultrasound apparatus. Diagnostic catheterisation can be avoided in many cases. In addition changes of form and position of the bladder can be exactly determined.

Female↗