Investigation into Causes of Abnormal Cerebral MRI Findings Following PVAC Duty‐Cycled,Phased RF Ablation of Atrial Fibrillation

Asymptomatic Cerebral Lesions with Phased RF. Introduction: Left atrial catheter ablation of the pulmonary veins (PVs) is an established option for patients with atrial fibrillation (AF). Asymptomatic cerebral emboli (ACE) detected by diffusion weighted MRI (DW‐MRI) following AF ablation has been reported at varying rates. This variability may be linked to procedural variables and demographic risk factors. Animal studies with the multielectrode pulmonary vein ablation catheter (PVAC) have identified potential sources of emboli, including air introduced during PVAC introduction, inadequate anticoagulation, and high current densities when the distal (E1) and proximal (E10) electrodes are in contact. We sought to evaluate the incidence, size, and number of DW‐MRI findings with procedural modifications that potentially reduce the embolic load. Methods: Thirty‐seven AF patients (59 ± 10 years, 73% male, all with paroxysmal AF, left atrial [LA] diameter 44 ± 7 mm, left ventricular ejection fraction 57 ± 7%) underwent MRI sequences preceding ablation, within 24 hours postablation, and at 4–6 weeks. During the procedure all patients were on uninterrupted phenprocoumon, an attempted activated clotting time (ACT) level >300 seconds, had the PVAC introduced under saline, and antral ablation was started with a 2:1 bipolar/unipolar mode. Files from the ablation unit (GENius v14.4) were retrospectively analyzed to determine the relationship between E1 and E10 in close proximity and DW‐MRI findings. Results: Post procedure, 10/37 patients (27%) were positive for new DWI cerebral lesions. Nine of 10 patients had a single lesion, and 1/10 patient had 2 lesions. Average lesion size was 3.1 ± 3.9 mm (2–14 mm). One of 10 (10%) had lesions at MRI follow‐up. No neurological symptoms were observed. Eighteen of 37 (49%) of procedures had evidence of E1/E10 interaction. In the subgroup of patients with and without E1 and E10 in close proximity, the DW‐MRI rate was 8/18 (44%) and 2/19 (11%), respectively (P = 0.029). Conclusions: The source of positive DW‐MRI findings in LA ablation involves several factors. Controlling anticoagulation and careful sheath management helps to reduce the number and size of DW‐MRI lesions. With the PVAC catheter, an ablation with the E1 and E10 in close proximity increases the risk of a DW‐MRI finding. In the future, electrodes E1 and E10 should be kept apart to help reduce the incidence of acute ACE. (J Cardiovasc Electrophysiol, Vol. 24, pp. 121‐128, February 2013)     

Electrical Proarrhythmia: Induction of Inappropriate Atrial Therapies due to Far-Field R Wave Oversensing in a New Dual Chamber Defibrillator

R Wave Far-Field Sensing in Dual Chamber Defibrillators . This case report describes delivery of atrial therapies during a sinus tachycardia in a new dual chamber implantable cardioverter defibrillator inappropriately caused by far-field oversensing of ventricular beats in the atrial channel. Upon classification of the PR interval pattern, the rate criterion for an atrial tachycardia was fulfilled, and the device initiated high-frequency burst pacing as the first stage of programmed tiered atrial therapies. Atrial fibrillation subsequently was induced by high-frequency burst pacing, and eventually a programmed 10-J shock was delivered for successful termination of atrial fibrillation. The phenomenon of far-field oversensing of ventricular beats could be repeatedly observed during exercise testing and abolished by decreasing the atrial sensitivity.     

Induced gall-bladder contraction accelerates fragment clearance after extracorporeal shockwave lithotripsy

At the end of extracorporeal shockwave lithotripsy (ESWL) gallstone fragments are dispersed throughout the gall-bladder. In this state they should be expelled more easily than when later sedimented to the gall-bladder fundus. Thus, a randomized study was performed to evaluate the clinical benefit of induced gall-bladder contraction after ESWL. One hundred and five patients with radiolucent gallstones (1–3 stones, diameter ≤ 30 mm) were randomized to received either saline or an infusion of 0.2 μg/kg ceruletide. Stone clearance rates and incidence of biliary symptoms were recorded. Clearance rates at 6 weeks and 3 months after ESWL were significantly (P≤ 0.025) improved by the ceruletide infusion. This effect, resulting in shortened bile acid therapy, was limited to patients with small solitary stones and dependent on a good initial fragmentation. Major side effects attributable to ceruletide were not observed. These results suggest that induced gall-bladder contraction can be successfully applied as an adjuvant treatment in a subgroup of patients with small solitary gallstones.     

Percutaneous Catheter Ablation at the Mitral Annulus in Canines Using a Bipolar Epicardial-Endocardial Electrode Configuration

For potential application in ablating left free-wall accessory AV pathways with direct current shocks, a new epicardial-endocardial electrode configuration, designed to focus the current field across the mitral annulus, was tested in dogs. A catheter electrode in (he coronary sinus (epicardial electrode) was used as the cathode, and a catheter electrode in the left ventricle (endocardial electrode) placed beneath the mitral valve, high against the mitral annulus and directly across from the epicardial electrode formed the anode. Two shocks, each of 30, 40, or 50 joules (J) were delivered in nine, three, and four dogs, respectively. The first shock was applied to the anterior or lateral wail and the second shock to the posterior wall, except in one dog which received one anterior and one lateral shock. Two dogs receiving 50] shocks died acutely, one due to rupture of the coronary sinus and cardiac tamponade and the other had unexplained electromechanical dissociation. The remaining 14 dogs tolerated the two shocks well and were sacrificed 3–5 days later for pathological examination of the heart. Shocks in the anterior and lateral regions produced atrial necrosis (height 1.5–11 mm, width 1.5–12 mm and depth 1–3 mm) in 10 of 14 dogs and ventricular necrosis (height 4–27 mm, width 4–33 mm, and depth 5–14 mm) in all 14 dogs. Ideal lesions with atrial necrosis extending down to the annulus and ventricular necrosis extending to the epicardial aspect of the ventricular crest occurred in five dogs in which the endocardial electrode was positioned high against the annulus. In the other nine dogs, the endocardial electrode was located 6–18 mm below the annulus, as estimated by the center of ventricular necrosis. In these dogs, the ventricular lesions did not extend to the epicardial aspect of the crest and, in four dogs, no atrial necrosis was found. Shocks delivered to the posterior wall produced no atrial or ventricular necrosis except in one dog receiving a 50 J shock. It is concluded that, using the epicardial-endocardial electrode configuration with the LV catheter positioned high against the annulus, shocks of less than 50 J in dogs safely produce atrial and ventricular necrosis adjacent to the mitral annulus in the anterior and lateral regions but not in the posterior regions. Similar lesions in man may be capable of interrupting left anterior and lateral accessory AV pathways.     

Standardized Assessment of Psychological Well-Being and Quality-of-Life in Patients with Implanted Defibrillators

The ICD has become a standard treatment for patients with malignant arrhythmias. Despite its benefits it may cause additional discomfort to the patients. Thus, quality-of-life needs to be assessed in these patients. Previous studies have used only small samples or unstandardized measures of quality-of-life that do not allow comparisons with other patient groups. The present study used standardized questionnaires for a cross-sectional assessment of psychological well-being and quality-of-life in ICD patients and to compare them to a similar group of coronary artery disease (CAD) patients without ICD. Overall, quality-of life did not differ between both groups, ICD patients being less anxious than the CAD group. With increasing numbers of ICD shocks, however, the percentage of psychologically distressed ICD patients rose from 10% to > 50%. Psychologically distressed patients had significantly worse scores on most of the quality-of-life subscales, showed less treatment satisfaction, and more negative attitudes. It is concluded that ICD patients have an acceptable mean quality-of-life and low mean anxiety. However, a relevant subgroup of about 15%, especially patients with frequent shocks, experience psychological distress and reduced quality-of-life and should receive special care.     

PR Interval Adaptation in the Denervated Transplanted Heart

In the present study, the dynamic PR response upon standardized treadmill exercise was investigated in 21 transplant recipients (recipient age 48 ± 17 years, donor age 31 ± 12 years, > 1 year after transplantation). MR and PR interval were measured at rest and at the end of each 25-Wincrease in workload till peak exercise. In 17 cases norepinephrine (NE) was assessed at rest, and at the end of each workload the MR increased from 99.3 ± 14 to 143.4 ± 25 beats/min at individual peak exercise, and NE increased from 1.307 ± 1,163 to 3.688 ± 2.036 pg/mL. while the PR interval shortened from 149.2 ± 13 to 119.3 ± 20 ms. On average. PR decreased by 3.4 ms for a 10-beat increase in HR, and the HR-PR interval relationship was described by a linear regression (y = 176.8–0.3469x, P = 0.0001). One patient who was unable to increase his NE levels upon exercise showed virtually no decrease in the PR interval and no HR increase. Both recipient age and donor age were moderately and significantly related to the minimum PR interval achieved at peak exercise (r = 0.6. P = 0.008 and r = 0.51. P = 0.049, respectively). These data show the following: (1) adaptation of the PR interval upon exercise does occur in the denervated transplanted heart; (2) the HR-PR relation is similar to that reported in the innervated heart; (3) the overall decline in PR interval is blunted, since denervated patients start at shorter resting PR intervals and achieve relatively longer PR intervals at peak exercise when compared to their innervated counterparts; (4) these exercise induced changes of the PR interval may be explained by circulating NE; and (5) NE levels achieved at peak exercise and the sensitivity of the AV node to NE seem to be age related. (PACE 1997; 20[Pt. I]:1247-1251)     

Dignified death: A German perspective

Abstract After discussing some defining questions concerning dignified death, active and passive euthanasia, assisted suicide and the criteria for free will and informed consent, the juridical situation in Germany is reported. Passive euthanasia according to the patients' free will is accepted, assisted suicide, active euthanasia, and passive euthanasia without informed consent are not accepted. The ethical discussion on these topics in Germany reveals a spectrum of opinions. There is somewhat more emphasis on the cons than on the pros. Humanistic and economic arguments merge in the debate. The philosophy of consequentialistic utilitarianism is heavily criticized by many authors who warn that respect even for the unproductive life must not fade. After some remarks on empirical studies on attitudes towards death and the history of attitudes towards euthanasia the conclusion lists the arguments, pros and cons, and gives a personal view.     

FN14 Signaling Plays a Pathogenic Role in a Mouse Model of Experimental Autoimmune Myocarditis

BackgroundThe pathogenesis of inflammatory cardiomyopathy is affected by the activation of autoimmune-mediated cascades. To study these cascades, we developed an experimental model of troponin I (TnI)-induced autoimmune myocarditis (EAM). One factor playing a pivotal role in the context of autoimmune disorders is the receptor fibroblast growth factor-inducible 14 (FN14). Thus, the impact of FN14 in the development of autoimmune myocarditis was investigated.Methods and ResultsTnI-immunization led to a significantly increased myocardial FN14 mRNA and protein expression in wild-type (wt) mice. To investigate the precise role of FN14 in EAM, FN14 knockout (ko) and wt littermates were immunized with TnI or control buffer. The animals were evaluated for cardiac parameters and indicators of myocardial injury. FN14 deficiency resulted in better cardiac performance, less myocardial inflammation, fibrosis, and cardiac damage. A lower myocardial mRNA expression of inflammatory cytokines and chemokines as well as their receptors could be demonstrated in TnI-immunized FN14ko compared to wt mice also immunized with TnI. Western blot analysis revealed a contribution of nuclear factor kappa-light-chain-enhancer of activated B cells to FN14-induced signaling cascades.ConclusionsIn the pathogenesis of autoimmune myocarditis, the inflammatory response to cardiac injury is attenuated in FN14ko mice. Thus, inhibition of FN14 in patients might represent a novel therapeutic strategy in the treatment of inflammatory cardiomyopathy.