Automatic detection of conducted premature atrial contractions to predict atrial fibrillation in patients after cardiac surgery

Abstract Introduction Atrial fibrillation (AFIB) is a common arrhythmia that is prevalent in post-cardiovascular surgery patients. It has been clinically observed Several studies that focused on developing methods to predict AFIB are described in the literature. Many of them In addition to the above-mentioned ECG characteristics, clinical studies The overall goal of our research is to develop PAC based predictors of AFIB by analyzing the occurrences and patterns of PACs over a long duration. These predictors will be developed such that they can be clinically applied to monitor post-surgical patients who have undergone cardiac surgery. To achieve the above goal it is imperative that a method be developed to automatically detect and classify PACs in the ECG. This technique should function reliably and in real-time to be clinically applicable. The current paper describes the development and verification of such a technique. Using this technique it is demonstrated how ECG signals from Cardio-Vascular ICU (CVICU) patients can be analyzed to evaluate the occurrence of PACs before the onset of AFIB. Methods A Premature Atrial Contraction (PAC) is a stimulus from an ectopic atrial site that travels across the atria via atypical pathways. The PAC stimulus precedes the stimulus originating from the SA-node. A PAC that gets propagated through the AV node into the ventricular region thus triggering a ventricular contraction is called

CARDIOVASCULAR MEDICINE C reactive protein concentration and recurrence of atrial fibrillation after electrical cardioversion

Background: To test the hypothesis that a high C reactive protein (CRP) concentration would predict recurrence of atrial fibrillation (AF) after cardioversion in patients taking antiarrhythmic drugs. Methods: 111 patients who underwent direct current cardioversion for symptomatic AF were enrolled. Blood was drawn for CRP determination before cardioversion on the same day. All patients were taking antiarrhythmic drugs before and after electrical cardioversion. Results: After a mean follow up of 76 days, 75 patients had recurrence of AF. In univariate analysis, the median CRP concentration was significantly higher in patients with AF recurrence (3.95 mg/l v 1.81 mg/l, p = 0.002). Among the 55 patients with CRP in the upper 50th centile, 44 (80%) experienced recurrence of AF over a total follow up of 8.98 patient years, whereas among the 56 patients with CRP in the lower 50th centile, 31 (55%) experienced recurrence of AF over a total follow up of 14.3 patient years (p , 0.001). The adjusted hazard ratio comparing the upper 50th centile of CRP with the lower 50th centile of CRP was 2.0 (95% confidence interval 1.2 to 3.2, p = 0.007). Conclusions: CRP is independently associated with recurrence of AF after electrical cardioversion among patients taking antiarrhythmic drugs. These results suggest that inflammation may have a role in the pathogenesis of AF resistant to antiarrhythmic drugs

A statistical method for retrospective cardiac and respiratory motion gating of interventional cardiac x-ray images

Purpose: Image-guided cardiac interventions involve the use of fluoroscopic images to guide the insertion and movement of interventional devices. Cardiorespiratory gating can be useful for 3D reconstruction from multiple x-ray views and for reducing misalignments between 3D anatomical models overlaid onto fluoroscopy. Methods: The authors propose a novel and potentially clinically useful retrospective cardiorespiratory gating technique. The principal component analysis (PCA) statistical method is used in combination with other image processing operations to make our proposed masked-PCA technique suitable for cardiorespiratory gating. Unlike many previously proposed techniques, our technique is robust to varying image-content, thus it does not require specific catheters or any other optically opaque structures to be visible. Therefore, it works without any knowledge of catheter geometry. The authors demonstrate the application of our technique for the purposes of retrospective cardiorespiratory gating of normal and very low dose x-ray fluoroscopy images. Results: For normal dose x-ray images, the algorithm was validated using 28 clinical electrophysiology x-ray fluoroscopy sequences (2168 frames), from patients who underwent radiofrequency ablation (RFA) procedures for the treatment of atrial fibrillation and cardiac resynchronization therapy procedures for heart failure. The authors established end-systole, end-expiration, and end-inspiration success rates of 97.0%, 97.9%, and 97.0%, respectively. For very low dose applications, the technique was tested on ten x-ray sequences from the RFA procedures with added noise at signal to noise ratio (SNR) values of √50, √10, √8, √6, √5, √2 and √1 to simulate the image quality of increasingly lower dose x-ray images. Even at the low SNR value of √2, representing a dose reduction of more than 25 times, gating success rates of 89.1%, 88.8%, and 86.8% were established. Conclusions: The proposed technique can therefore extract useful information from interventional x-ray images while minimizing exposure to ionizing radiation. © 2014 American Association of Physicists in Medicine

2017 HRS/EHRA/ECAS/APHRS/SOLAECE expert consensus statement on catheter and surgical ablation of atrial fibrillation: executive summary.

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C reactive protein concentration and recurrence of atrial fibrillation after electrical cardioversion

Background: To test the hypothesis that a high C reactive protein (CRP) concentration would predict recurrence of atrial fibrillation (AF) after cardioversion in patients taking antiarrhythmic drugs. Methods: 111 patients who underwent direct current cardioversion for symptomatic AF were enrolled. Blood was drawn for CRP determination before cardioversion on the same day. All patients were taking antiarrhythmic drugs before and after electrical cardioversion. Results: After a mean follow up of 76 days, 75 patients had recurrence of AF. In univariate analysis, the median CRP concentration was significantly higher in patients with AF recurrence (3.95 mg/l v 1.81 mg/l, p  =  0.002). Among the 55 patients with CRP in the upper 50th centile, 44 (80%) experienced recurrence of AF over a total follow up of 8.98 patient years, whereas among the 56 patients with CRP in the lower 50th centile, 31 (55%) experienced recurrence of AF over a total follow up of 14.3 patient years (p < 0.001). The adjusted hazard ratio comparing the upper 50th centile of CRP with the lower 50th centile of CRP was 2.0 (95% confidence interval 1.2 to 3.2, p  =  0.007). Conclusions: CRP is independently associated with recurrence of AF after electrical cardioversion among patients taking antiarrhythmic drugs. These results suggest that inflammation may have a role in the pathogenesis of AF resistant to antiarrhythmic drugs