Learning-based hypothesis fusion for robust catheter tracking in 2D X-ray fluoroscopy

Repeat accessory pathway ablation: Challenges, surprises, and lessons learned

X-ray fluoroscopically guided cardiac electrophysiological procedures are routinely carried out for diagnosis and treatment of cardiac arrhythmias. X-ray images have poor soft tissue contrast and, for this reason, overlay of static 3D roadmaps derived from pre-procedural volumetric data can be used to add anatomical information. However, the registration between the 3D roadmap and the 2D X-ray data can be compromised by patient respiratory motion. We propose a novel method to correct for respiratory motion using real-time image-based coronary sinus (CS) catheter tracking. The first step of the proposed technique is to use a blob detection method to detect all possible catheter electrodes in the Xray data. We then compute a cost function to select one CS catheter from all catheter-like objects. For correcting respiratory motion, we apply a low pass filter to the 2D motion of the CS catheter and update the 3D roadmap using this filtered motion. We tested our CS catheter tracking method on 1048 fluoroscopy frames from 15 patients and achieved a success rate of 99.3% and an average 2D tracking error of 0.4 mm +/- 0.2 mm. We also validated our respiratory motion correction strategy by computing the 2D target registration error (TRE) at the pulmonary veins and achieved a TRE of 1.6 mm +/- 0.9 mm.

Coronary sinus (CS) catheterization is critical during catheter ablation (CA) of atrial fibrillation (AF). However, the association of CS electrical activity with atrial substrate modification has been barely investigated and mostly limited to analyses during AF. In sinus rhythm (SR), atrial substrate modification is principally assessed at a global level through P-wave analysis. Cross-correlating CS electrograms (EGMs) and P-waves’ features could potentiate the understanding of AF mechanisms. Five-minute surface lead II and bipolar CS recordings before, during, and after CA were acquired from 40 paroxysmal AF patients. Features related to duration, amplitude, and heart-rate variability of atrial activations were evaluated. Heart-rate adjustment (HRA) was applied. Correlations between each P-wave and CS local activation wave (LAW) feature were computed with cross-quadratic sample entropy (CQSE), Pearson correlation (PC), and linear regression (LR) with 10-fold cross-validation. The effect of CA between different ablation steps was compared with PC. Linear correlations: poor to mediocre before HRA for analysis at each P-wave/LAW (PC: max. +18.36%, p = 0.0017, LR: max. +5.33%, p = 0.0002) and comparison between two ablation steps (max. +54.07%, p = 0.0205). HRA significantly enhanced these relationships, especially in duration (P-wave/LAW: +43.82% to +69.91%, p < 0.0001 for PC and +18.97% to +47.25%, p < 0.0001 for LR, CA effect: +53.90% to +85.72%, p < 0.0210). CQSE reported negligent correlations (0.6–1.2). Direct analysis of CS features is unreliable to evaluate atrial substrate modification due to CA. HRA substantially solves this problem, potentiating correlation with P-wave features. Hence, its application is highly recommended.

Catheter ablation is widely accepted as the best remaining option for the treatment of atrial fibrillation if drug therapy fails. Ablation procedures can be guided by 3-D overlay images projected onto live fluoroscopic X-ray images. These overlay images are generated from either MR, CT or C-Arm CT volumes. As the alignment of the overlay is often compromised by cardiac and respiratory motion, motion compensation methods are desirable. The most recent and promising approaches use either a catheter in the coronary sinus vein, or a circumferential mapping catheter placed at the ostium of one of the pulmonary veins. As both methods suffer from different problems, we propose a novel method to achieve motion compensation for fluoroscopy guided cardiac ablation procedures. Our new method localizes the coronary sinus catheter. Based on this information, we estimate the position of the circumferential mapping catheter. As the mapping catheter is placed at the site of ablation, it provides a good surrogate for respiratory and cardiac motion. To correlate the motion of both catheters, our method includes a training phase in which both catheters are tracked together. The training information is then used to estimate the cardiac and respiratory motion of the left atrium by observing the coronary sinus catheter only. The approach yields an average 2-D estimation error of 1.99 ± 1.20 mm.KeywordsPulmonary VeinLeft AtriumRespiratory MotionAblation ProcedureMotion CompensationThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Clinical Case: A 51 year old male with a history of hypertension, G6PD deficiency, thrombotic thrombocytopenic purpura, prior stroke, and morbid obesity presented with resuscitated out of hospital VF arrest. Electrolytes and ECG were normal. During his admission, the patient had two VF events that were induced by what appeared to be a short coupled right bundle branch block (RBBB) morphology PVC. He was brought to the electrophysiology lab for PVC ablation and ICD implantation. Baseline rhythm was sinus with what appeared to be both RBBB morphology PVCs and junctional extrasystoles. With both extrasystoles, the His potential preceded the QRS by 50 ms, and atrial activation in the His catheter and coronary sinus catheter was also earlier than the QRS. Activation mapping of the right bundle showed later activation than the His potential. This was all consistent with junctional premature complexes (JPC) with frequent RBBB aberrancy rather than fascicular PVCs. Slow pathway modification was performed to attempt to ablate the JPCs. After multiple ablations along the tricuspid annulus and back to the coronary sinus os that triggered slow junctional beats, the patient’s JPC burden was significantly reduced. An ICD was also implanted. The patient was discharged on flecainide. At 4 month follow up he had not had recurrence. Discussion: Early coupled PVCs are a well-known cause of ventricular fibrillation, but JPCs inducing VF have not been described previously. Placement of a coronary sinus and His catheter helped identify early that this was not simply a fascicular PVC. This case demonstrates the importance of keeping a broad differential diagnosis when starting any EP study. Ablating the slow pathway area can be effective to treat JPCs while preserving native AV conduction as demonstrated in this case.

Effectiveness and Safety of the Femoral Venous Approach for Coronary Sinus Catheterization in Children

Preferential conduction patterns along the coronary sinus during atrial fibrillation in humans and their modification by pulmonary vein isolation

Identifying Origin of Nonpulmonary VeinTriggers Using 2 Stationary LinearDecapolar Catheters: A Novel Algorithm.

Catheter Ablation of Atypical Atrial Flutter and Atrial Tachycardia Within the Coronary Sinus After Left Atrial Ablation for Atrial Fibrillation

An 82-year-old man with a history of diabetes mellitus, hypertension, chronic kidney disease, polycythemia, hypothyroidism, T-cell lymphoma, and prostate cancer presented with complaints of dyspnea on exertion for several months. He underwent extensive evaluation including an echocardiogram, which showed normal left ventricular systolic function with an ejection fraction of 63%, left ventricular hypertrophy, moderate aortic stenosis, and mild to moderate aortic regurgitation. A cardiac catheterization showed normal filling pressures with moderate aortic stenosis. He was thought to have tachy-brady syndrome because of episodes of rapid atrial fibrillation and sinus bradycardia at rest. Because of exercise associated fatigue and dyspnea, the patient was referred for pacemaker implantation. Careful inspection of hospital telemetry revealed frequent atrial premature contractions (APCs), often in a bigeminal pattern, which blocked in the AV node and caused compensatory reset of the sinus node, …

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The motion and deformation of catheters that lie inside cardiac structures can provide valuable information about the motion of the heart. In this paper we describe the formation of a novel statistical model of the motion of a coronary sinus (CS) catheter based on principal component analysis of tracked electrode locations from standard mono-plane x-ray fluoroscopy images. We demonstrate the application of our model for the purposes of retrospective cardiac and respiratory gating of x-ray fluoroscopy images in normal dose x-ray fluoroscopy images, and demonstrate how a modification of the technique allows application to very low dose scenarios. We validated our method on ten mono-plane imaging sequences comprising a total of 610 frames from ten different patients undergoing radiofrequency ablation for the treatment of atrial fibrillation. For normal dose images we established systole, end-inspiration and end-expiration gating with success rates of 100%, 92.1% and 86.9% respectively. For very low dose applications, the method was tested on the same ten mono-plane x-ray fluoroscopy sequences without noise and 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. The method was able to detect the CS catheter even in the lowest SNR images with median errors not exceeding 2.6 mm per electrode. Furthermore, gating success rates of 100%, 71.4% and 85.7% were achieved at the low SNR value of √2, representing a dose reduction of more than 25 times. Thus, the technique has the potential to extract useful information whilst substantially reducing the radiation exposure.

Four patients with left-sided accessory pathways (APs) and unusual coronary sinus (CS) received radiofrequency ablation. Unusual CS included occlusion of CS (patient 1), acute angulation of proximal CS (patients 2 and 3), and narrowing of CS orifice and proximal segment (patient 4). CS catheterization and AP mapping along the CS could not be performed in the four patients. Radiofrequency ablation by left ventricular retrograde technique for the manifest left posteroseptal AP (patient 1), concealed left posterior AP (patient 2), and transseptal left atrial technique for the manifest left posteroseptal AP (patient 3) and manifest left posterior AP (patient 4) were performed successfully without CS catheter guidance. This study suggests that radiofrequency ablation of left-sided AP with unusual CS is feasible by some special techniques.

New cardiological techniques such as coronary sinus catheterization and selective catheterization of the cardiac veins permit the opening of new experimental and clinical fields, for instance in venous angiography and the reverse nourishment of myocardium which is endangered by ischemia,and also in the electrophysiological study of the components of the conduction system. New approaches in heart surgery, such as the removal of accessory pathways of the conduction system (as in WPW syndrome), necessitate the realization of the topographical relationships of the vessels in the various sections of the coronary sulci in a different way. The objective of this work is, therefore, to present comprehensive and almost new macro- and microanatomical data about the venous drainage of the myocardium via the coronary sinus and its related and unrelated (non-coronary) cardiac veins. Examination of meticulously dissected heart specimens (of individuals who had achieved old or extreme old age at the time of their death in Germany: n=250) as well as corrosion casts of adult cardiac vessels (of individuals of all ages, n=25) formed the basis for the exact description and documentation of the occurrence, frequency, origin, and courses of both the normal and anomalously developed human coronary sinus and cardiac veins. A wide range of morphological and experimental references was consulted in order to enable thorough discussion of the anatomical findings in the light of modern cardiological diagnostics and treatment. The anatomical and clinical nomenclature is presented and there is a brief comment on modern diagnostic techniques and their applications where the cardiac veins are concerned. The two principal and one compound cardiac venous system are defined and discussed with reference to the existence of both the normal and anomalous coronary sinus and cardiac vein. 1. The greater (major) cardiac venous system (2) The smaller (minor) cardiac venous system (3)The compound cardiac venous system. The microanatomy of the various proper cardiac veins is not very well explained and illustrated in old or new literature; therefore, special attention is paid in the present study to the detailed microanatomy of the cardiac venous drainage. This includes the topograpy and structural and surface anatomy of the coronary sinus (position, length and shape, diameters, area of cross-section, circumference and volume, curvature, elevation, ostial angle, enlargement, duplication, absence), and the exact enternal and internal morphological landmarks of the coronary sinus with reference to its myocardial cover, isolated myocardial belts, and "free" myocardial cords which connect the atrial and ventricular myocardium, and the atrial ostium of the coronary sinus. It is established that the frequency, distribution pattern, courses and mode of opening of the major ventricular and atrial cardiac veins and the occurrence, morphology, and efficiency of the ostial valves of the coronary sinus and its tributaries all influence the success of any selective catheter implantation and venous reperfusion technique to a great degree. There are many peculiarities of the cardiac veins which are worthy of consideration, for instance intramyocardial and aberrant courses of the anterior interventricular vein, the oblique vein of the left atrium, the posterior interventricular vein, the small cardiac vein, the posterior vein of the left ventricle, the left and right marginal veins, and the anterior cardiac veins. Various forms and courses of the intramural venous tunnel, sinus or channel of the right atrium were found and illustrated, and discussed in terms of developmental and comparative anatomy. This review incorporates a great variety of clinically significant, new morphological findings with regard to the coronary sinus and the cardiac venous system. The many anatomical peculiarities and hindrances to the catheterization of the coronary sinus and the reperfusion of (even selected) cardiac veins are documented and evaluated; the various problems which may arise in venous reperfusion due to the presence of anatomical anomalies of the coronary sinus, cardiac veins, and ostial valves (of greater or lesser efficiency) are addressed. The presentation narrows a gap in the rather incomplete knowledge of the venous drainage of the human myocardium.

Atrial Effective Refractory Periods in Patients With Frequent Premature Atrial Complexes: Implications for Atrial Fibrillation.