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Aims: The morphology of unipolar single potentials (SPs) contains information on intra-atrial conduction disorders and possibly the substrate underlying atrial fibrillation (AF). This study examined the impact of AF episodes on features of SP morphology during sinus rhythm (SR) in patients with mitral valve disease.Methods and Results: Intraoperative epicardial mapping (interelectrode distance 2 mm) of the right and left atrium (RA, LA), Bachmann's bundle (BB), and pulmonary vein area (PVA) was performed in 67 patients (27 male, 67 ± 11 years) with or without a history of paroxysmal AF (PAF). Unipolar SPs were classified according to their differences in relative R- and S-wave amplitude ratios. A clear predominance of S-waves was observed at BB and the RA in both the no AF and PAF groups (BB 88.8% vs. 85.9%, RA 92.1% vs. 85.1%, respectively). Potential voltages at the RA, BB, and PVA were significantly lower in the PAF group (P < 0.001 for each) and were mainly determined by the size of the S-waves amplitudes. The largest difference in S-wave amplitudes was found at BB; the S-wave amplitude was lower in the PAF group [4.08 (2.45-6.13) mV vs. 2.94 (1.40-4.75) mV; P < 0.001]. In addition, conduction velocity (CV) at BB was lower as well [0.97 (0.70-1.21) m/s vs. 0.89 (0.62-1.16) m/s, P < 0.001].Conclusion: Though excitation of the atria during SR is heterogeneously disrupted, a history of AF is characterized by decreased SP amplitudes at BB due to loss of S-wave amplitudes and decreased CV. This suggests that SP morphology could provide additional information on wavefront propagation. [ABSTRACT FROM AUTHOR]

Objective: Surgical left atrial appendage (LAA) closure using epicardial clips has become popular in stroke prevention in patients with atrial fibrillation. Optimal placement of the clip is essential to achieve complete LAA occlusion and to prevent complications due to compression of the circumflex artery. We determine the added value of immersive virtual reality (VR) in accurately assessing LAA base size and selection of an appropriately sized clip. Methods: We studied the feasibility of measuring the LAA base using VR and conventional computed tomography (CT). A retrospective analysis was performed of LAA base measurements in 15 patients who had undergone thoracoscopic LAA clipping. Subsequently, we compared the placed clip size with imaging-acquired LAA base size to retrospectively evaluate intraprocedural sizing. Results: We successfully applied a VR platform to measure LAA base size. The median LAA base size measured in CT (23.8 mm, interquartile range [IQR] 22.3 to 26.4 mm) and intracardial virtual reality (23.4 mm, IQR 21.6 to 25.5 mm) did not differ significantly ( P  = 0.416). VR measurements of the LAA base in surgeon's view (25.7 mm, IQR 24.2 to 29.2) were significantly higher than those of 2-dimensional CT ( P  = 0.037) and intracardial 3-dimensional (3D) VR ( P  < 0.05) measurements. All measurements differed significantly with placed clip sizes ( P  < 0.05). There were no clip malpositioning-related events. Conclusions: Immersive VR is a feasible method for obtaining anatomical information on LAA base size. In this retrospective analysis, CT and VR-based measurements of LAA base size differed significantly from intraoperatively placed LAA clips, indicating potential oversizing when measured intraoperatively. Using intuitive 3D VR-based imaging might be a useful method to assist in accurate preprocedural sizing of LAA base and can potentially prevent oversizing.

Introduction: Advancing age is a known risk factor for developing atrial fibrillation (AF), yet it is unknown which electrophysiological changes contribute to this increased susceptibility. The goal of this study is to investigate conduction disturbances and unipolar voltages (UV) related to aging., Methods: We included 216 patients (182 male, age: 36-83 years) without a history of AF undergoing elective coronary artery bypass surgery. Five seconds of sinus rhythm were recorded intraoperatively at the right atrium (RA), Bachmann's bundle (BB), the left atrium and the pulmonary vein area (PVA). Conduction delay (CD), -block (CB), -velocity (CV), length of longest CB lines and UV were assessed in all regions., Results: With aging, increasing conduction disturbances were found, particularly at RA and BB (RA: longest CB line r s  = .158, p = .021; BB: CB prevalence r s  = .206, p = .003; CV r s  = -.239, p < .0005). Prevalence of low UV areas (UV <5th percentile) increased with aging at the BB and PVA (BB: r s  = .237, p < .0005 and PVA: r s  = .228, p = .001)., Conclusions: Aging is accompanied by an increase in conduction disturbances during sinus rhythm and a higher prevalence of low UV areas, particularly at BB and in the RA. These electrophysiological alterations could in part explain the increasing susceptibility to AF development associated with aging., (© 2021 The Authors. Journal of Cardiovascular Electrophysiology published by Wiley Periodicals LLC.)

Aims: Increased complexity in cardiac surgery over the last decades necessitates more precise preoperative planning to minimize operating time, to limit the risk of complications during surgery and to aim for the best possible patient outcome. Novel, more realistic, and more immersive techniques, such as three-dimensional (3D) virtual reality (VR) could potentially contribute to the preoperative planning phase. This study shows our initial experience on the implementation of immersive VR technology as a complementary research-based imaging tool for preoperative planning in cardiothoracic surgery. In addition, essentials to set up and implement a VR platform are described., Methods: Six patients who underwent cardiac surgery at the Erasmus Medical Center, Rotterdam, The Netherlands, between March 2020 and August 2020, were included, based on request by the surgeon and availability of computed tomography images. After 3D VR rendering and 3D segmentation of specific structures, the reconstruction was analysed via a head mount display. All participating surgeons ( n  = 5) filled out a questionnaire to evaluate the use of VR as preoperative planning tool for surgery., Conclusion: Our study demonstrates that immersive 3D VR visualization of anatomy might be beneficial as a supplementary preoperative planning tool for cardiothoracic surgery, and further research on this topic may be considered to implement this innovative tool in daily clinical practice., Lay Summary: Over the past decades, surgery on the heart and vessels is becoming more and more complex, necessitating more precise and accurate preoperative planning. Nowadays, operative planning is feasible on flat, two-dimensional computer screens, however, requiring a lot of spatial and three-dimensional (3D) thinking of the surgeon. Since immersive 3D virtual reality (VR) is an upcoming imaging technique with promising results in other fields of surgery, we aimed in this study to explore the additional value of this technique in heart surgery. Our surgeons planned six different heart operations by visualizing computed tomography scans with a dedicated VR headset, enabling them to visualize the patient's anatomy in an immersive and 3D environment. The outcomes of this preliminary study are positive, with a much more reality-like simulation for the surgeon. In such, VR could potentially be beneficial as a preoperative planning tool for complex heart surgery., (© The Author(s) 2020. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Aims: The morphology of unipolar single potentials (SPs) contains information on intra-atrial conduction disorders and possibly the substrate underlying atrial fibrillation (AF). This study examined the impact of AF episodes on features of SP morphology during sinus rhythm (SR) in patients with mitral valve disease., Methods and Results: Intraoperative epicardial mapping (interelectrode distance 2 mm) of the right and left atrium (RA, LA), Bachmann's bundle (BB), and pulmonary vein area (PVA) was performed in 67 patients (27 male, 67 ± 11 years) with or without a history of paroxysmal AF (PAF). Unipolar SPs were classified according to their differences in relative R- and S-wave amplitude ratios. A clear predominance of S-waves was observed at BB and the RA in both the no AF and PAF groups (BB 88.8% vs. 85.9%, RA 92.1% vs. 85.1%, respectively). Potential voltages at the RA, BB, and PVA were significantly lower in the PAF group (P < 0.001 for each) and were mainly determined by the size of the S-waves amplitudes. The largest difference in S-wave amplitudes was found at BB; the S-wave amplitude was lower in the PAF group [4.08 (2.45-6.13) mV vs. 2.94 (1.40-4.75) mV; P < 0.001]. In addition, conduction velocity (CV) at BB was lower as well [0.97 (0.70-1.21) m/s vs. 0.89 (0.62-1.16) m/s, P < 0.001]., Conclusion: Though excitation of the atria during SR is heterogeneously disrupted, a history of AF is characterized by decreased SP amplitudes at BB due to loss of S-wave amplitudes and decreased CV. This suggests that SP morphology could provide additional information on wavefront propagation., (© The Author(s) 2020. Published by Oxford University Press on behalf of the European Society of Cardiology.)