44 research outputs found
Clinical Impact of Atrial Fibrillation in Patients with Pulmonary Hypertension
BACKGROUND: Pulmonary hypertension (PH) is associated with progressive impairment of right ventricular function, reduced exercise capacity and a poor prognosis. Little is known about the prevalence, clinical manifestation and impact of atrial fibrillation (AF) on cardiac function in PH. METHODS: In a four year single-centre retrospective analysis 225 patients with confirmed PH of various origins were enrolled to investigate the prevalence of AF, and to assess the clinical manifestation, 6-minute walk distance, NT-proBNP levels, echocardiographic parameters and hemodynamics obtained by right heart catheterization in PH with AF. RESULTS: AF was prevalent in 31.1%. In patients with PH and AF, parameters of clinical deterioration (NYHA/WHO functional class, 6-minute walk distance, NT-proBNP levels) and renal function were significantly compromised compared to patients with PH and sinus rhythm (SR). In the total PH cohort and in PH not related to left heart disease occurrence of AF was associated with an increase of right atrial pressure (RAP) and right atrial dilatation. While no direct association was found between pulmonary artery pressure (PAP) and AF in these patients, right ventricular function was reduced in AF, indicating more advanced disease. In PH due to left heart failure the prevalence of AF was particularly high (57.7% vs. 23.1% in other forms of PH). In this subgroup, left atrial dilatation, increase of pulmonary capillary wedge pressure, PAP and RAP were more pronounced in AF than in SR, suggesting that more marked backward failure led to AF in this setting. CONCLUSION: PH is associated with increased prevalence of AF. Occurrence of AF in PH indicates clinical deterioration and more advanced disease
Intraoperative Defibrillation Testing of Subcutaneous Implantable CardioverterâDefibrillator SystemsâA Simple Issue?
Background: The results of the recently published randomized SIMPLE trial question the role of routine intraoperative defibrillation testing. However, testing is still recommended during implantation of the entirely subcutaneous implantable cardioverterâdefibrillator (SâICD) system. To address the question of whether defibrillation testing in SâICD systems is still necessary, we analyzed the data of a large, standardâofâcare prospective singleâcenter SâICD registry. // Methods and Results: In the present study, 102 consecutive patients received an SâICD for primary (n=50) or secondary prevention (n=52). Defibrillation testing was performed in all except 4 patients. In 74 (75%; 95% CI 0.66â0.83) of 98 patients, ventricular fibrillation was effectively terminated by the first programmed internal shock. In 24 (25%; 95% CI 0.22â0.44) of 98 patients, the first internal shock was ineffective and further internal or external shock deliveries were required. In these patients, programming to reversed shock polarity (n=14) or repositioning of the sensing lead (n=1) or the pulse generator (n=5) led to successful defibrillation. In 4 patients, a safety margin of <10 J was not attained. Nevertheless, in these 4 patients, ventricular arrhythmias were effectively terminated with an internal 80âJ shock. // Conclusions: Although it has been shown that defibrillation testing is not necessary in transvenous ICD systems, it seems particular important for SâICD systems, because in nearly 25% of the cases the primary intraoperative test was not successful. In most cases, a successful defibrillation could be achieved by changing shock polarity or by optimizing the shock vector caused by the pulse generator or lead repositioning.<br
Impact of cavotricuspid isthmus ablation for typical atrial flutter and heart failure in the elderlyâresults of a retrospective multi-center study
IntroductionWhile in the CASTLE-AF trial, in patients with atrial fibrillation and heart failure with reduced ejection fraction, interventional therapy using pulmonary vein isolation was associated with outcome improvement, data on cavotricuspid isthmus ablation (CTIA) in atrial flutter (AFL) in the elderly is rare.MethodsWe included 96 patients between 60 and 85 years with typical AFL and heart failure with reduced or mildly reduced ejection fraction (HFrEF/HFmrEF) treated in two medical centers. 48 patients underwent an electrophysiological study with CTIA, whereas 48 patients received rate or rhythm control and guideline-compliant heart failure therapy. Patients were followed up for 2 years, with emphasis on left ventricular ejection fraction (LVEF) over time. Primary endpoints were cardiovascular mortality and hospitalization for cardiac causes.ResultsPatients with CTIA showed a significant increase in LVEF after 1 (pâ<â0.001) and 2 years (pâ<â0.001) in contrast to baseline LVEF. Improvement of LVEF in the CTIA group was associated with significantly lower 2-year mortality (pâ=â0.003). In the multivariate regression analysis, CTIA remained the relevant factor associated with LVEF improvement (HR: 2.845 CI:95% 1.044â7.755; pâ=â0.041). Elderly patients (â„ 70 years) further benefited from CTIA, since they showed a significantly reduced rehospitalization (pâ=â0.042) and mortality rate after 2 years (pâ=â0.013).ConclusionsCTIA in patients with typical AFL and HFrEF/HFmrEF was associated with significant improvement of LVEF and reduced mortality rates after 2 years. Patient age should not be a primary exclusion criterion for CTIA, since patients â„70 years also seem to benefit from intervention in terms of mortality and hospitalization
Absorbing customer knowledge: how customer involvement enables service design success
Customers are a knowledge resource outside of the firm that can be utilized for new service success by involving them in the design process. However, existing research on the impact of customer involvement (CI) is inconclusive. Knowledge about customersâ needs and on how best to serve these needs (articulated in the service concept) is best obtained from customers themselves. However, codesign runs the risk of losing control of the service concept. This research argues that of the processes of external knowledge, acquisition (via CI), customer knowledge assimilation, and concept transformation form a capability that enables the firm to exploit customer knowledge in the form of a successful new service. Data from a survey of 126 new service projects show that the impact of CI on new service success is fully mediated by customer knowledge assimilation (the deep understanding of customersâ latent needs) and concept transformation (the modification of the service concept due to customer insights). However, its impact is more nuanced. CI exhibits an ââ©â-shaped relationship with transformation, indicating there is a limit to the beneficial effect of CI. Its relationship with assimilation is âUâ shaped, suggesting a problem with cognitive inertia where initial learnings are ignored. Customer knowledge assimilation directly impacts success, while concept transformation only helps success in the presence of resource slack. An evolving new service design is only beneficial if the firm has the flexibility to adapt to change
Selective inhibition of the pacemaker channel If improves symptoms in severe dilated cardiomyopathy
Activation of Reverse Na+-Ca2+ Exchange by the Na+ Current during an Action Potential Augments the Calcium Transient: Evidence from NCX Knockout Mice
By Regulating Mitochondrial Ca2+-Uptake UCP2 Modulates Intracellular Ca2+.
The possible role of UCP2 in modulating mitochondrial Ca2+-uptake (mCa2+-uptake) via the mitochondrial calcium uniporter (MCU) is highly controversial.Thus, we analyzed mCa2+-uptake in isolated cardiac mitochondria, MCU single-channel activity in cardiac mitoplasts, dual Ca2+-transients from mitochondrial ((Ca2+)m) and intracellular compartment ((Ca2+)c) in the whole-cell configuration in cardiomyocytes of wild-type (WT) and UCP2-/- mice.Isolated mitochondria showed a Ru360 sensitive mCa2+-uptake, which was significantly decreased in UCP2-/- (229.4±30.8 FU vs. 146.3±23.4 FU, P0.05) and transsarcolemmal Ca2+-influx was inhibited suggesting a possible compensatory mechanism. Additionally, we observed an inhibitory effect of ATP on mCa2+-uptake in WT mitoplasts and (Ca2+)m of cardiomyocytes leading to an increase of (Ca2+)c while no ATP dependent effect was observed in UCP2-/-.Our results indicate regulatory effects of UCP2 on mCa2+-uptake. Furthermore, we propose, that previously described inhibitory effects on MCU by ATP may be mediated via UCP2 resulting in changes of excitation contraction coupling
Cardiac Sympathetic Activity and Rhythm Control Following Pulmonary Vein Isolation in Patients with Paroxysmal Atrial FibrillationâA Prospective 123I-mIBG-SPECT/CT Imaging Study
Background: Pulmonary vein isolation (PVI) and antiarrhythmic drug therapy are established treatment strategies to preserve sinus rhythm in atrial fibrillation (AF). However, the efficacy of both interventional and pharmaceutical therapy is still limited. Solid evidence suggests an important role of the cardiac sympathetic nervous system in AF. In this blinded, prospective observational study, we studied left ventricular cardiac sympathetic activity in patients treated with PVI and with antiarrhythmic drugs. Prospectively, Iodine-123-benzyl-guanidine single photon emission computer tomography (123I-mIBG-SPECT) was performed in a total of 23 patients with paroxysmal AF, who underwent PVI (n = 20) or received antiarrhythmic drug therapy only (n = 3), respectively. 123I-mIBG planar and SPECT/CT scans were performed before and 4 to 8 weeks after PVI (or initiation of drug therapy, respectively). For semiquantitative SPECT image analysis, attenuation-corrected early/late images were analyzed. Quantitative SPECT analysis was performed using the AHA 17-segment model of the left ventricle. Results: PVI with point-by-point radiofrequency ablation led to a significantly (p < 0.05) higher visual sympathetic innervation defect score when comparing pre-and post PVI. Newly emerging innervation deficits post PVI were localized predominantly in the inferior lateral wall. These findings were corroborated by semiquantitative SPECT analysis identifying inferolateral segments with a reduced tracer uptake in comparison to SPECT before PVI. Following PVI, patients with an AF relapse showed a different sympathetic innervation pattern compared to patients with sufficient rhythm control. Conclusions: PVI results in novel defects of cardiac sympathetic innervation. Differences in cardiac sympathetic innervation remodelling following PVI suggest an important role of the cardiac autonomous nervous system in the maintenance of sinus rhythm following PVI