Use of CAD led to a significant increase in sensitivity for detecting polyps in the 6 mm or larger and 6-9 mm groups at the expense of a similar significant reduction in specificity.

Aortic stenosis (AS) is the most common valvular heart disease in industrialised countries with a prevalence of about 5 % in the general population aged greater than 75 years. During the past decade, transcatheter aortic valve replacement (TAVR) has emerged as a valuable, minimally invasive treatment option for patients presenting with symptomatic severe AS, who due to their advanced age and relevant comorbidities are at prohibitive risk for conventional surgery, 1 whereas surgical aortic valve replacement (SAVR) remains the gold standard for the treatment of symptomatic AS in patients with low to moderate surgical risk.2 However, many patients begin to experience AS-related symptoms late in their lives when multiple comorbidities preclude surgery as an option. As a result, before the advent of TAVR, patients considered high-or extreme-risk surgical candidates were once limited to conventional medical therapy. Ever since the first device was deployed in 2002, TAVR has enabled inoperable patients the opportunity to experience survival rates equivalent to their surgical counterparts with considerably less procedural risk.1 Therefore, the number of patients undergoing TAVR has increased steadily, and the complications related to valve implantation have been well defined.The development of atrioventricular (AV) conduction disturbances is one of the most commonly encountered complications associated with TAVR. Between 3 and 6 % of patients undergoing surgical replacement of their aortic valve will develop complete heart block (CHB), 3 while considerably higher rates have been reported in the setting of TAVR in individual studies. 4 In this review, we aim to explore the significance of conduction disturbances preceding and resulting from TAVR. We have focused on data that raise concerns around creating chronic left ventricular (LV) dyssynchrony in this patient population, either as a consequence of creating left bundle branch block (LBBB), or from chronic right ventricular (RV) pacing. Additionally, we reviewed a number of factors that predispose TAVR patients to develop conduction disturbances, and clinical factors that can be used to identify those patients likely to require permanent pacing and alternatively those in whom it may be worth waiting longer prior to committing to permanent pacemaker (PPM) implantation. Shy of unique valve designs, it has become clear there are only modest improvements an operator can make to avoid the complication of heart block and this complication is simply part of the procedure. It is critical to anticipate it and think prospectively about the ideal pacing mode for the individual patient to prevent chronic LV dyssynchrony in those patients at highest risk. Mechanisms of Heart Block Anatomical Relationship of the Cardiac Conduction System and the Aortic RootSince the 16th century when Leonardo da Vinci conducted the first known cadaveric studies of the heart, the aortic root complex has been studied extensively. With the advent of percutaneous valves, there has been renewed interest ...

The CAD system evaluated has a high level of performance in the detection of adenomatous polyps with CTC data from a polyp-enriched cohort different from that used to train the system.

L(M3D) best approximated polyp size measurements at optical colonoscopy. Linear diameter calculated from automated volume measurements showed the smallest variation between supine and prone scans while avoiding observer variability and may be best for assessing polyp size changes with serial examinations.

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Frequent ventricular pacing is often or completely unavoidable in patients with high-grade or complete heart block. Over time, patients with high-burden RV pacing are at risk for developing symptomatic cardiomyopathy due to pacing-induced ventricular dyssynchrony. Growing awareness of this concern has generated interest in alternative pacing sites like the septum and outflow tract, the thinking being that these sites will more closely mimic His-Purkinje-mediated ventricular activation. Numerous studies have met with mixed results likely due to the fact that-to quote Marvin Gaye-there ain't nothing like the real thing. Herein lies the advantage of His bundle pacing (HBP), as it is the only pacing modality capable of physiological ventricular activation. HBP has been demonstrated to be safe and reliable in various forms of AV block with minimal drawbacks, namely modestly higher pacing thresholds when compared with other RV sites. Additionally, HBP is a truly physiologic alternative to biventricular pacing to effect cardiac resynchronization therapy (CRT), a concept supported by small observational and prospective studies. In our view, His bundle pacing should be considered in nearly all patients requiring ventricular pacing.

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Aims The treatment of atrial fibrillation beyond pulmonary vein isolation has remained an unsolved challenge. Targeting regions identified by different substrate mapping approaches for ablation resulted in ambiguous outcomes. With the effective refractory period being a fundamental prerequisite for the maintenance of fibrillatory conduction, this study aims at estimating the effective refractory period with clinically available measurements. Methods and results A set of 240 simulations in a spherical model of the left atrium with varying model initialization, combination of cellular refractory properties, and size of a region of lowered effective refractory period was implemented to analyse the capabilities and limitations of cycle length mapping. The minimum observed cycle length and the 25% quantile were compared to the underlying effective refractory period. The density of phase singularities was used as a measure for the complexity of the excitation pattern. Finally, we employed the method in a clinical test of concept including five patients. Areas of lowered effective refractory period could be distinguished from their surroundings in simulated scenarios with successfully induced multi-wavelet re-entry. Larger areas and higher gradients in effective refractory period as well as complex activation patterns favour the method. The 25% quantile of cycle lengths in patients with persistent atrial fibrillation was found to range from 85 to 190 ms. Conclusion Cycle length mapping is capable of highlighting regions of pathologic refractory properties. In combination with complementary substrate mapping approaches, the method fosters confidence to enhance the treatment of atrial fibrillation beyond pulmonary vein isolation particularly in patients with complex activation patterns.