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Biomedical subjects

W Jung

Publications and source records attributed to W Jung.

At least 19 recordsLinked to original sources
PubMed1996

Quality of life and driving in recipients of the implantable cardioverter-defibrillator.

UNLABELLED: The efficacy of a treatment is primarily based on objective criteria, such as mortality and morbidity. Besides these criteria, the interest in measuring quality of life (QOL) in relation to health care has increased in recent years. Although the concept of patients' QOL is inherently subjective, and definitions vary, it can be assessed on a basis of 3 major components: physical condition, psychological well-being, and social activities. The basic requirements of QOL assessments are: multidimensional construct, reliability, validity, sensitivity, responsiveness, appropriateness to question or use, and practical utility. The instruments to assess QOL can be disease specific or generic, depending on the context. In 1991 a prospective and systematic evaluation of QOL in implantable cardioverter-defibrillator (ICD) recipients was started at the University of Bonn: psychological profile and patient acceptance were assessed in 57 consecutive patients using a specifically designed questionnaire. The results of this pilot study demonstrated that the acceptance of the ICD was remarkably high. Restrictions on driving a vehicle may have a substantial impact on QOL in patients with ICDs. A specifically designed questionnaire was addressed to 47 European national delegates in order to determine their present practices and criteria utilized when advising driving restrictions to patients after ICD implantation. Of the 39 (83%) respondents, 22 (56%) cardiologists advised all patients to abstain from driving--13 (33%) advising permanent abstinence, while 26 (67%) recommended temporary driving abstinence for periods of 3-18 months (mean 9 +/- 4 months). Despite medical advice not to drive, one third of the patients resume driving; half of the patients resumed driving after 6 months, with the vast majority driving within 12 months after ICD surgery. Two patients experienced ICD discharges while driving, but no motor vehicle accident occurred. Another patient had a motor vehicle collision with a fatal outcome, which was not caused by loss of consciousness or ICD discharge. CONCLUSIONS: (1) Fatal accidents or ICD discharges while driving are a rare finding in ICD patients. (2) About half of the physicians always advise their patients to cease driving for a period of 9 +/- 4 months. Despite this medical advice, the majority of the patients resume driving within 6 months of ICD implantation. (3) Criteria used in advising driving abstinence are not uniform among physicians.

Attitude↗
PubMed1996

T cells from patients with Hodgkin's disease have a defective T-cell receptor zeta chain expression that is reversible by T-cell stimulation with CD3 and CD28.

To investigate the mechanisms underlying the deficiency of T lymphocytes from patients with Hodgkin's disease, we investigated the expression of the T-cell receptor (TCR) zeta chain in patients with Hodgkin's disease. By flow cytometry using an anti-zeta chain monoclonal antibody, peripheral blood T lymphocytes from patients with untreated Hodgkin's disease were shown to express decreased levels of the TCR zeta chain. After stimulation by combined CD3 and CD28 cross-linking, T cells from Hodgkin's disease patients upregulated zeta chain protein expression to normal values within 48 hours and achieved a cytolytic potential and levels of interleukin (IL)-2 secretion that were not different from T cells obtained from healthy controls. These results show that downregulation of the TCR zeta chain in Hodgkin's T lymphocytes is a reversible event. Costimulation of CD3 and CD28 is a novel approach for overcoming the T-cell deficiency in Hodgkin's disease and might be exploited clinically. As upregulation of the zeta chain can also be achieved using bispecific monoclonal antibodies (BI-MoAbs) with specificity for tumor antigens and CD3 and CD28, respectively, an immunotherapy with CD3/CD30 and CD28/CD30 Bi-MoAbs may overcome and should therefore, not be jeopardized by the inherent T-cell deficiency in patients with Hodgkin's disease.

Adolescent↗
PubMed1996

Cure of disseminated xenografted human Hodgkin's tumors by bispecific monoclonal antibodies and human T cells: the role of human T-cell subsets in a preclinical model.

Cure of a single established human Hodgkin's tumor growing subcutaneously in severe combined immunodeficient (SCID) mice can be achieved with a complex protocol using two bispecific monoclonal antibodies (Bi-MoAb) directed against the Hodgkin's associated CD30 antigen and the T-cell triggering molecules CD3 and CD28, respectively, together with human T cells prestimulated in vitro with Bi-MoAbs in the presence of CD30+ cells. To adapt this model to the clinical situation, disseminated tumors were established in SCID mice by intravenous injection of 2 x 10(7) cells of the Hodgkin's derived cell line L540CY. Treatment of SCID mice bearing disseminated CD30+ Hodgkin's tumors with the combination of CD3/CD30 and CD28/CD30 Bi-MoAbs and naive (ie, not in vitro prestimulated) human T cells resulted in the cure of all appropriately treated animals. T lymphocytes obtained from patients with advanced stage untreated Hodgkin's disease were as effective as lymphocytes from healthy controls. Treatment was effective even when delayed until 2 weeks after tumor inoculation, and application of Bi-MoAbs into SCID mice with circulating human T cells was as effective as injecting the Bi-MoAbs before the lymphocytes. Treatment results with isolated CD4+ and CD8+ human T cells suggest that both subsets are necessary for the Bi-MoAb mediated cure of xenografted human tumors in vivo. The efficacy and practicability of this preclinical immunotherapy protocol support and form the basis for the clinical evaluation of this approach in patients with Hodgkin's disease resistant to standard therapy.

Animals↗
PubMed1996

[Driving of a motor vehicle after implantation of a cardioverter-defibrillator in malignant heart rhythm disorders. Criteria for the medical assessment of driving fitness in Europe].

AIM OF STUDY: To investigate how medical permission to drive in patients with a cardioverter defibrillator is handled in various European countries. METHODS: A specially developed questionnaire was sent to all 46 delegates of the pacemaker groups of the European Society of Cardiology. They were asked to provide information on the procedures and criteria used in the various countries regarding a driving ban after cardioverter defibrillator implantation (ICD). RESULTS: 39 answers (83%) were received from representatives of 24 countries. 22 (56%) of those replying advised their patients not to drive. A permanent driving ban was recommended by 13 (33%), a temporary one of 3-18 (mean 9 +/- 4) months by 26 (67%). Presyncope was named as a criterion for a ban by 15 (38%), syncope by 13 (33%) and multiple defibrillator shocks by two (5%). Contrary to medical advice not to drive about one third of patients resumed driving, half of them after 6 months. 12 months after implantation most of the patients were again driving. Defibrillator discharges occurred in 2 patients, without consequence. One patient had a fatal car accident, unrelated to loss of consciousness or defibrillator shock. CONCLUSIONS: 1. ICD discharges are an extremely rare cause of driving accidents. 2. About half of the cardiologists recommended a driving ban for a mean of 9 months after ICD. 3. Despite medical ban about half of the patients resumed driving after 6 months. 4. There are as yet no uniform criteria in Europe for judging fitness to drive.

Accidents, Traffic↗
PubMed1996

Nonpharmacologic strategies for treating atrial fibrillation.

Nonpharmacologic tools to treat atrial fibrillation (AF) are direct current cardioversion, radiofrequency (RF) current catheter ablation, antiarrhythmic surgery, pacing, and atrial defibrillation. In patients with sustained AF, when no cause can be found for AF or when the associated disease is mild, an attempt should be made to restore sinus rhythm. Electrical cardioversion by synchronized direct current shock can be attempted when drugs have failed and is the first choice in acutely ill patients. Virtually all patients should be anticoagulated. Temporary pacing should be available in patients with evidence of previous bradycardia. Although efficacy may be improved in patients pretreated with antiarrhythmic drugs, there is a considerable risk of adverse events. In AF and sinus node dysfunction, both pacing and antiarrhythmic drugs may be necessary. Pacing should be atrial or dual chamber, since ventricular pacing provokes AF. Failure to control the ventricular rate in AF can be treated by RF: atrioventricular (AV) node ablation, ablation of accessory pathways in preexcitation syndrome with AF, modulation of AV node, or ablation of AF. Antiarrhythmic surgery is a major procedure and may be the therapy of last resort in AF: the so-called corridor procedure isolates the fibrillating atria from a strip of tissue connecting the sinus and AV nodes. The maze procedure attempts to abolish AF by channeling the atrial activation between a series of incisions. In patients with chronic AF, internal cardioversion should be attempted if conventional transthoracic electrical cardioversion is ineffective. Several studies demonstrated the feasibility and efficacy of internal atrial defibrillation in selected patients with recent onset, as well as with chronic, AF. An implantable atrial defibrillator--as a stand-alone device or as part of a whole heart cardioverter--might be an option in the future. Nonpharmacologic tools play only a minor role in the management of paroxysmal and chronic AF. If symptoms persist despite pharmacologic therapy and other causes of persisting symptoms are excluded, consideration should be given to cardiac pacing, RF catheter treatment, or surgery. in some cases nonpharmacologic therapy of the AV node must be followed by implantation of a permanent pacemaker (due to complete AV block) and anticoagulation (due to persistence of underlying AF.

Adolescent↗
PubMed1996

Influence of captopril on nitroglycerin-mediated vasodilation and development of nitrate tolerance in arterial and venous circulation.

We investigated whether captopril is able to potentiate vasodilation and prevent tolerance to a 48-hour infusion of nitroglycerin (NTG). Twenty-six patients were randomly assigned to a 7-day regimen of captopril (50 mg/day) or placebo. The hemodynamic response to a 0.8 mg sublingual NTG dose was assessed by measuring mean arterial pressure (MAP), mean pulmonary artery pressure (PAP), pulmonary capillary wedge pressure (PCWP), right atrial pressure (RAP), and cardiac output (CO), and calculating systemic (SVR) and pulmonary vascular resistances (PVR). The parameters were obtained serially at baseline and 1 to 10 minutes after the sublingual NTG application (day 1). Then intravenous NTG was started and maintained for 48 hours (1.5 micrograms/kg/min), and the hemodynamic study was repeated (day 3). There was no difference between the captopril and the placebo groups at day 1 (baseline values and response to sublingual NTG). After the 48-hour infusion, there was a complete loss of the NTG effects in the placebo group (day 1 vs day 3: PAP, 20 +/- 5 mm Hg vs 21 +/- 8 mm Hg; MAP, 86 +/- 11 mm Hg vs 90 +/- 9 mm Hg; SVR, 1295 +/- 330 mm Hg vs 1380 +/- 465 dyne.sec.cm-5) whereas there was still evidence of a persistent vasodilation in the captopril group (day 1 vs day 3: PAP, 19 +/- 4 mm Hg vs 13 +/- 4 mm Hg; MAP, 84 +/- 9 mm Hg vs 74 +/- 10 mm Hg; SVR, 1265 +/- 280 mm Hg vs 1140 +/- 425 dyne.sec.cm-5). The response to sublingual NTG on day 3 was markedly attenuated in the placebo group only. We conclude that captopril does not increase the vasodilatory response to nitroglycerin but is able to prevent developing nitrate tolerance in arterial and venous circulation.

Administration, Sublingual↗
PubMed1996

Treatment of Hodgkin's disease with bispecific antibodies.

Bispecific monoclonal antibodies (Bi-MAbs) with dual specificity for tumor-associated antigens (TAA) and a triggering molecule of an immunologic effector cell, respectively, open the possibility to specifically target to and activate cytotoxic effector cells (macrophages, T-cells, NK cells) at the tumor site. Using appropriately designed Bi-MAbs and unstimulated human NK cells and T-cells, respectively, we were able to cure SCID mice xenografted with human Hodgkin's tumors. This approach was also effective in disseminated tumors and when treatment was delayed until three weeks after the inoculation of the tumor, thus establishing this approach as the most effective model of an immunomodulating therapy of human neoplasms. Early observations with an ongoing phase I/II study with CD16/CD30 Bi-MAb in patients with refractory Hodgkin's disease confirm the expected low toxicity. If these observations can be confirmed in larger clinical studies, effector cell activating Bi-MAbs could become an important weapon in the remaining fight for the conquest of Hodgkin's disease.

Animals↗
PubMed1996

Direct angiography of the coronary sinus: impact on left posteroseptal accessory pathway ablation.

The purpose of this study was to determine the incidence and types of venous branches and anomalies in posteroseptal accessory pathways (APs) and whether these findings are indicative for successful ablation sites. Some posteroseptal APs may be located epicardially, or may be associated with venous anomalies or related to the middle cardiac vein. These APs account for many of the failures encountered during endocardial ablation. Direct coronary sinus (CS) angiography was performed in 43 consecutive patients with left posteroseptal APs (n = 23) and in 20 patients with AV nodal reentrant tachycardia prior to catheter ablation. In 14 (61%) of 23 APs, a venous branch or an anomaly of the CS was found in the posteroseptal region (6 with middle cardiac vein, 2 with other ventricular venous branches, and 6 had a diverticulum). Eleven (48%) of 23 APs were successfully abolished from within that demonstrated venous system, with a median of four radiofrequency impulses. In the remaining 12 (52%) patients, ablation was attempted from the endocardial site of the mitral annulus. Repeat angiography after energy delivery revealed no major complications in any patient. One (5%) patient with AV nodal reentrant tachycardia had evidence of a CS anomaly (P < 0.01). Various types of venous branches and anomalies are associated with the majority of patients with left posteroseptal APs. The APs are directly related to these complex findings, and AP conduction can easily be eliminated from within the venous branches. CS angiography is suggested prior to catheter ablation of left posteroseptal APs to facilitate the ablation procedure.

Adult↗
PubMed1996

[Clinical experiences with pectoral defibrillator implantation].

UNLABELLED: The pectoral approach to implantation of cardioverter/defibrillators has the aim to further simplify the implantation of transvenous defibrillation systems. The PCD 7219 D/C is a device of the fourth generation which makes the pectoral implantation feasible due to a weight of 132 g, a size of 89 x 64 x 18 mm, a volume of 83 cm3 and a surface of 108 cm2. The use of the "active-can"-system (PCD 7219 C) requires the implantation of only one right ventricular lead. The PCD 7219 D/C was implanted in 75 patients with ventricular tachyarrhythmias, the follow-up period was 12 +/- 4 (1-24) months. Subpectoral implantation was feasible in 59 patients (79%), in 55 with a left pectoral, in 4 with a right pectoral approach due to previous left-sided operation or thrombosis of the left subclavian vein. Male sex (p < 0.005), body weight (p < 0.005) and body surface (p < 0.05) were predictors of pectoral implantation. In the 45 patients (60%) with a unipolar defibrillation system ("active can") the defibrillation threshold was significantly lower compared to those with a dual lead system (9.9 +/- 6.5, 2.5-24 Joule vs. 19 +/- 4.5, 6-24 Joule p < 0.0001). In one patient with pectoral and in one patient with abdominal implantation a dislodgement of the right ventricular lead was diagnosed and an operative revision was indicated. CONCLUSION: The down-sized implantable cardioverter/defibrillator PCD 7219 D/C makes the pectoral implantation feasible in the majority of patients. The use of the "active-can"-system requires the implantation of only one right ventricular lead with significantly lower defibrillation thresholds.

Adolescent↗
PubMed1996

Multicenter experience with a pectoral unipolar implantable cardioverter-defibrillator. Active Can Investigators.

OBJECTIVES: The purpose of this study was to prospectively examine in a multicenter study the methods of use, efficacy and complications of a unipolar cardioverter-defibrillator in patients at risk for sudden cardiac death. BACKGROUND: Implantation of cardioverter-defibrillators in the pectoral region offers a significant opportunity to improve the management of patients with life-threatening arrhythmias. Unipolar, single-lead, pectoral implantable cardioverter-defibrillators might decrease related mortality, morbidity and costs in the care of such patients. METHODS: From November 3, 1993 to May 8, 1995, a unipolar defibrillator (Medtronic model 7219C) was selected for use in 473 patients from 74 centers (386 [82%] men, 87 [18%] women; mean [+/- SD] age 59 +/- 13 years, range 16 to 88). The clinical indication for use was ventricular fibrillation in 157 patients, sustained ventricular tachycardia in 236, both ventricular tachycardia and ventricular fibrillation in 53 and syncope or inducible ventricular tachycardia/ventricular fibrillation in 27. Coronary artery disease was present in 323 patients (68%). The mean left ventricular ejection fraction was 0.36 +/- 0.15 (range 0.10 to 0.85). The distribution of New York Heart Association congestive heart failure was class I = 34%; class II = 45%; class III = 17%; and class IV = 2%. RESULTS: The unipolar cardioverter-defibrillator was inserted successfully in 464 (98%) of 473 candidates. Effective defibrillation occurred with the first shock polarity tested in 88% of patients, after a polarity switch in 8% and after lead or generator repositioning in 2%. The stored energy defibrillation threshold was obtained at implantation in 339 patients (72%) and was 11.5 +/- 6.1 J, with 72% of patients having a defibrillation threshold < or = 12 J. The mean "skin-to-skin" implantation time was 96 +/- 45 min (range 25 to 335 min). Complications occurred in 29 patients (6%). Device therapy for 2,160 spontaneous ventricular tachycardia or fibrillation episodes occurred in 128 patients (27%) over a 2,732 device-month experience (range 0 to 17.2) and was effective in 98.7% of episodes. There were 14 deaths (10 nonsudden cardiac, 3 sudden cardiac, 1 noncardiac). Cumulative survival, on an intention-to-treat basis from all causes of death at 17.2 months, was 94.4%. CONCLUSIONS: Unipolar pectoral implantable cardioverter-defibrillators can be inserted with a high likelihood of success in a relatively brief procedure. Defibrillation thresholds are low, morbidity is modest, and survival rates are good with this new type of implantable cardioverter-defibrillator.

Cardiac Pacing, Artificial↗
PubMed1995

Heart rate to work rate relation throughout peak exercise in normal subjects as a guideline for rate-adaptive pacemaker programming.

We investigated the physiologic heart rate (HR) to work rate (WR) relation throughout peak exercise in normal subjects as a guideline for rate-adaptive pacemaker slope programming. The study group consisted of 41 middle-aged subjects (22 men and 19 women) without evidence of cardiopulmonary disease. Peak-exercise stress tests were performed on a calibrated treadmill by using the symptom-limited "ramping incremental treadmill exercise" (RITE) protocol. The HR response, oxygen uptake, and treadmill workload increments were assessed simultaneously. The HR/WR slope, as determined using linear regression analysis, was 0.37 +/- 0.13 beats/min/W for the entire study group, which indicates an upper range increase of 5 beats/10 W increase of external treadmill work performed, using the mean value +/- 1 SD. Men generated an HR/WR slope of 0.32 +/- 0.09 beats/min/W, and women, 0.43 +/- 0.15 beats/min/W, indicating a significant sex-related difference in the HR/WR relation (p < 0.01). Thus, to achieve an appropriate matching of HR with patient effort, rate-adaptive pacemakers should generate an average increase of approximately 5 beats per increase in 10 W of external treadmill work. The HR/WR relation can easily be determined to provide the clinician with a minimal check system to avoid a hyper- or hypochronotropic paced response to exercise.

Adult↗
PubMed1995

The role of lymphocyte subsets and adhesion molecules in T cell-dependent cytotoxicity mediated by CD3 and CD28 bispecific monoclonal antibodies.

The cure of human Hodgkin's tumors heterotransplanted into SCID mice can be achieved by two bispecific monoclonal antibodies (Bi-mAb) directed against the tumor-associated CD30 antigen and CD3 and CD28, respectively, and normal peripheral human blood T cells. We investigated the role of lymphocyte subsets and adhesion molecules in this Bi-mAb-mediated cytolysis. CD4+ lymphocytes were the most rapidly expanding subpopulation, but Bi-mAb-directed cytotoxicity was mediated preferentially by CD8+ lymphocytes and effector cells belonging to the CD45RO+ "memory" pool. Blocking of the LFA-1/ICAM-1 or CD2/LFA-3 adhesion pathways by mAb decreased Bi-mAb-mediated cytotoxicity. This was not due to inhibition of aggregate formation between Bi-mAb-coated T lymphocytes and target cells. Cross-linking of LFA-1 or CD2 molecules on lymphocytes prestimulated with Bi-mAb bound to CD3 and CD28 antigen lead to a more pronounced and prolonged rise in the intracellular concentration of free Ca2+. Additional CD2 cross-linking resulted in the tyrosine phosphorylation of distinct proteins. These findings indicate that adhesion molecules play a critical role and function as co-stimulatory signals rather than as cellular contact mediators in CD3 and CD28 Bi-mAb-stimulated T lymphocytes.

Antibodies, Bispecific↗
PubMed1995

Prospective study of retrograde coronary venography in patients with posteroseptal and left-sided accessory atrioventricular pathways.

The morphologic features of the coronary vein system was prospectively studied with retrograde venography in 117 patients with left-sided (78 patients) and posteroseptal accessory pathway (39). Findings were compared with accessory pathway localization. A mean of 3.3 +/- 1.5 venous branches draining into the coronary sinus or the great cardiac vein could be visualized. The morphologic condition was described and classified. Incidence, morphologic condition, and distribution did not differ between left-sided and posteroseptal accessory pathway. Venous abnormalities including ectasy, diverticulum, narrowing, angulation, and hypoplasia occurred in 22.2%. Diverticulum and narrowing were present in posteroseptal accessory pathway only and always related to the successful ablation site. In patients with left-sided accessory pathway, ectasy, angulation, and hypoplasia were found. Anomalies were less frequent (9% vs 43.6%, p < 0.001) and had no relation to accessory pathway localization. However, the successful ablation site was in 42.3% located < 5 mm to an angiographically visualized venous branch. In conclusion, posteroseptal accessory pathways are often related to coronary sinus abnormalities. In patients with a left-sided accessory pathway venous malformation is uncommon, whereas a close anatomic relation exists between accessory pathway localization and venous ventricular branches.

Adolescent↗
PubMed1995

Randomized comparison of aspirin and phenprocoumon for prevention of right-sided thromboembolic complications associated with transvenous defibrillation leads.

Death due to pulmonary embolism caused by thrombosis formation along a pacing wire has been reported in patients with antibradycardia pacemakers. The purpose of this prospective and randomized study was to evaluate the effects of prophylactically assigned aspirin (100 mg per day) or phenprocoumon (a coumarin derivative) on the incidence of right-sided thromboembolic complications associated with transvenous defibrillation leads. Multiplane transoesophageal echocardiography and pulmonary scintigraphy were performed in 62 consecutive patients immediately and 6 +/- 2 months after transvenous defibrillator implantation. Aspirin or phenprocoumon was administered to the patients in a randomized and parallel manner. By means of multiplane transoesophageal echocardiography and pulmonary scintigraphy no thromboembolic events were observed immediately after transvenous defibrillator implantation. After 6 +/- 2 months, however, multiplane transoesophageal echocardiography disclosed thrombi on the transvenous leads in 13 of 62 patients (21%) despite antithrombotic therapy. At the same time, pulmonary scintigraphy did not reveal any defects compatible with pulmonary embolism. Although thrombi occurred in only four patients treated with phenprocoumon, but in nine patients receiving aspirin, this difference was statistically insignificant. Other variables associated with the occurrence of thrombosis formation were not identified. One fatal intracranial haemorrhage occurred in the phenprocoumon group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

The "low intensity treadmill exercise" protocol for appropriate rate adaptive programming of minute ventilation controlled pacemakers.

The objective of rate adaptive pacemakers that measure minute ventilation by transthoracic impedance is to simulate the physiological relationship of the sensed signal to the sinus node response during exercise, thus achieving an appropriate matching of heart rate with patient effort. The purpose of this study was to determine the physiological relationship between heart rate and minute ventilation (HR/VE) during peak exercise testing in order to develop a database for appropriate rate adaptive slope programming of minute ventilation controlled pacemakers. Due to several clinical limitations of peak exercise testing, it was additionally determined whether the 35-watt "low intensity treadmill exercise" (LITE) protocol can be used as a substitute for peak exercise test using the "ramping incremental treadmill exercise" (RITE) protocol in order to assess the correct HR/VE slope below the anaerobic threshold. The stress tests were performed on a treadmill with the collection of breath-by-breath gas exchange. Linear regression analysis was used to determine the HR/VE slope below and above the anaerobic threshold and during the early, dynamic phase of low intensity exercise with the RITE and LITE protocols, respectively. The results of this testing in 41 healthy subjects demonstrated that the HR/VE relationship throughout treadmill exercise using the RITE protocol was not linear but curvilinear in nature, with a steeper HR/VE slope of 1.54 +/- 0.51 below versus 1.15 +/- 0.37 above the anaerobic threshold (P < 0.005). The HR/VE slope determined during the early, dynamic phase of the LITE protocol (1.58 +/- 0.88) did not differ from the HR/VE slope from rest to anaerobic threshold obtained using the peak exercise RITE test (1.54 +/- 0.51; P = 0.79). Rate adaptive pacing should simulate the curvilinear relationship between heart rate and minute ventilation from rest to peak exercise. The HR/VE slope determined during the early, dynamic phase of low intensity exercise represents the HR/VE slope derived from the RITE protocol below the anaerobic threshold. According to the peak exercise database, the slope above anaerobic threshold can easily be calculated as a percentage of the slope below the anaerobic threshold. The LITE protocol can, therefore, be effectively performed as a substitute for peak exercise stress tests to determine the correct pacemaker rate response factor in order to obtain a physiological heart rate to minute ventilation relationship for the appropriate matching of paced heart rate with patient effort.

Anaerobic Threshold↗
PubMed1995

Incidence of ICD lead related complications during long-term follow-up: comparison of epicardial and endocardial electrode systems.

UNLABELLED: The aim of this study was to evaluate the long-term stability of epicardial and endocardial lead systems for third-generation cardioverter defibrillators (ICDs) and to assess the usefulness of diagnostic tools. One hundred forty patients with 61 epicardial (43.6%) and 79 nonthoracotomy systems (56.4%) were followed for 25 +/- 19 months. A total of 18 (12.9%) lead related complications were documented. Complications of epicardial systems were detected in 10 patients (16.4%) during a follow-up time of 36 +/- 8 months: crinkling of patch electrodes in 6 patients (9.8%), insulation breakage of sensing electrodes in 2 patients (3.3%), and adapter defect in 2 patients (3.3%). Eight of the patients (10.1%) with transvenous-subcutaneous systems had lead related complications during a 13 +/- 6 months follow-up: fracture of the subcutaneous patch lead in 2 patients (2.5%), dislodgement of the right ventricular lead in 2 patients (2.5%), dislodgement of the superior vena cava lead in 2 patients (2.5%), insulation breakage of sensing electrodes in 1 patient (1.3%), and connector defect in 1 patient (1.3%). There was no significant difference in the incidence of lead related complications between epicardial and endocardial systems (P > 0.05). Fractures, dislodgements, and crinklings were documented within the first 8 +/- 5 months by regular chest X ray. Defects of insulation, adapter, or connector were detected 22 +/- 10 months after implantation and were associated with delivery of multiple inappropriate ICD therapies. An operative lead revision was indicated for 4 epicardial (6.6%) and 6 endocardial (7.6%) lead systems. CONCLUSIONS: Endocardial lead systems offer a similar long-term stability as compared to epicardial lead systems. Chest X ray is the most useful tool to detect lead fracture, dislodgment, and patch crinkling. Marker recordings or real-time electrograms have not been helpful in this series to identify patients with suspected lead defects prior to the experience of inappropriate ICD discharges.

Alloys↗