Endocardial Mapping Research Articles

Analysis of the driving mechanism in paroxysmal atrial fibrillation: comparison of the activation sequence between the left atrial body and pulmonary vein

BackgroundIt has been shown that most paroxysmal atrial fibrillation (AF) can be terminated by pulmonary vein (PV) isolation alone, suggesting that rapid discharges from PV drive AF. To define the driving mechanism of AF, we compared the activation sequence in the body of left atrium (LA) to that within PV. MethodsEndocardial noncontact mapping of LA body (LA group; n = 16) and selective endocardial mapping of left superior PV (LSPV) (PV group; n = 13) were performed in 29 paroxysmal AF patients. The frequency of pivoting activation, wave breakup, and wave fusion observed in LA were compared to those in LSPV to define the driving mechanism of AF. Circumferential ablation lesion around left PV was performed after right PV isolation to examine the effect of linear lesion around PV on AF termination both in LA and PV groups. ResultsThe frequency of pivoting activation, wave breakup, and wave fusion in PV group were significantly higher than those in LA group (36.5 ± 17.7 vs 5.0 ± 2.2 times/seconds, p < 0.001, 10.1 ± 4.3 vs 5.0 ± 2.2 times/seconds, p = 0.004, 18.1 ± 5.7 vs 11.0 ± 5.2, p = 0.002). Especially in the PV group, the frequency of pivoting activation was significantly higher than that of wave breakup and wave fusion (36.5 ± 17.7 vs 10.1 ± 4.3 times/seconds, p < 0.001, 36.5 ± 17.7 vs 18.1 ± 5.7 times/seconds, p < 0.001). These disorganized activations in LSPV were eliminated by the circumferential ablation lesion around left PV (pivoting activation; 36.5 ± 17.7 vs 9.3 ± 2.3 times/seconds, p < 0.001, wave breakup; 10.1±1.3 times/seconds, p = 0.003, wave fusion; 18.1 ± 5.7 vs 5.7 ± 1.8, p < 0.001), resulted in AF termination in all patients in both LA and PV groups. ConclusionsActivation sequence within PV was more disorganized than that in LA body. Frequent episodes of pivoting activation rather than wave breakup and fusion observed within PV acted as the driving sources of paroxysmal AF.

The influence of scar on the spatio-temporal relationship between electrical and mechanical activation in heart failure patients.

The aim of this study was to determine the relationship between electrical and mechanical activation in heart failure (HF) patients and whether electromechanical coupling is affected by scar. Seventy HF patients referred for cardiac resynchronization therapy or biological therapy underwent endocardial anatomo-electromechanical mapping (AEMM) and delayed-enhancement magnetic resonance (CMR) scans. Area strain and activation times were derived from AEMM data, allowing to correlate mechanical and electrical activation in time and space with unprecedented accuracy. Special attention was paid to the effect of presence of CMR-evidenced scar. Patients were divided into a scar (n = 43) and a non-scar group (n-27). Correlation between time of electrical and mechanical activation was stronger in the non-scar compared to the scar group [R = 0.84 (0.72-0.89) vs. 0.74 (0.52-0.88), respectively; P = 0.01]. The overlap between latest electrical and mechanical activation areas was larger in the absence than in presence of scar [72% (54-81) vs. 56% (36-73), respectively; P = 0.02], with smaller distance between the centroids of the two regions [10.7 (4.9-17.4) vs. 20.3 (6.9-29.4) % of left ventricular radius, P = 0.02]. Scar decreases the association between electrical and mechanical activation, even when scar is remote from late activated regions.

Characterization of Structural Changes in Arrhythmogenic Right Ventricular Cardiomyopathy With Recurrent Ventricular Tachycardia After Ablation: Insights From Repeat Electroanatomic Voltage Mapping.

Data characterizing structural changes of arrhythmogenic right ventricular (RV) cardiomyopathy are limited. Patients presenting with left bundle branch block ventricular tachycardia in the setting of arrhythmogenic RV cardiomyopathy with procedures separated by at least 9 months were included. Nineteen consecutive patients (84% males; mean age 39±15 years [range, 20-76 years]) were included. All 19 patients underwent 2 detailed sinus rhythm electroanatomic endocardial voltage maps (average 385±177 points per map; range, 93-847 points). Time interval between the initial and repeat ablation procedures was mean 50±37 months (range, 9-162). No significant progression of voltage was observed (bipolar: 38 cm2 [interquartile range (IQR), 25-54] versus 53 cm2 [IQR, 25-65], P=0.09; unipolar: 116 cm2 [IQR, 61-209] versus 159 cm2 [IQR, 73-204], P=0.36) for the entire study group. There was a significant increase in RV volumes (percentage increase, 28%; 206 mL [IQR, 170-253] versus 263 mL [IQR, 204-294], P<0.001) for the entire study population. Larger scars at baseline but not changes over time were associated with a significant increase in RV volume (bipolar: Spearman ρ, 0.6965, P=0.006; unipolar: Spearman ρ, 0.5743, P=0.03). Most patients with progressive RV dilatation (8/14, 57%) had moderate (2 patients) or severe (6 patients) tricuspid regurgitation recorded at either initial or repeat ablation procedure. In patients with arrhythmogenic RV cardiomyopathy presenting with recurrent ventricular tachycardia, >10% increase in RV endocardial surface area of bipolar voltage consistent with scar is uncommon during the intermediate term. Most recurrent ventricular tachycardias are localized to regions of prior defined scar. Voltage indexed scar area at baseline but not changes in scar over time is associated with progressive increase in RV size and is consistent with adverse remodeling but not scar progression. Marked tricuspid regurgitation is frequently present in patients with arrhythmogenic RV cardiomyopathy who have progressive RV dilation.

Percutaneous Epicardial Approach toCatheterAblation of CardiacArrhythmias.

Since their introduction >2 decades ago, percutaneous catheter-based epicardial mapping and ablation have become widely adopted by cardiac electrophysiologists around the world. Although epicardial mapping has been used for catheter ablation of a wide variety of cardiac arrhythmias, its most common use is for ablation of intramural and subepicardial substrates that give rise to ventricular tachycardia, particularly in patients with nonischemic cardiomyopathy. As such, the subxiphoid percutaneous epicardial approach has emerged as an important adjunct, and, in some cases, is the preferred strategy in this regard. This review discusses the rationale and indications for epicardial catheter mapping and/or ablation. This paper also reviews the prevalence of epicardial arrhythmias and their electrocardiographic criteria. In addition, it examines the anatomy of the pericardium and commonly used epicardial access techniques, as well as the optimal methodologies for epicardial mapping and ablation and the impact of epicardial fat. Finally, this review discusses the potential of the various complications associated with the percutaneous epicardial approach, in addition to patient-specific risk factors, and potential strategies to mitigate the risk of complications.

Одномоментное эндокардиальное и эпикардиальное картирование левого предсердия у пациентов с длительно персистирующей формой фибрилляции предсердий

Одномоментное эндокардиальное и эпикардиальное картирование левого предсердия у пациентов с длительно персистирующей формой фибрилляции предсердий

Classification of intracavitary electrograms in atrial fibrillation using information and complexity measures

BackgroundClassification of complex fractionated atrial electrograms is crucial for the study of atrial fibrillation and the development of treatment strategies, because these electrophysiological phenomena represent a common substrate for radiofrequency ablation in treatment of this arrythmia. ObjectiveThe objective of this work is the characterization of short term atrial electrograms using nonlinear dynamics measures, helping in the automatic classification of electrograms. MethodsThe dataset consists of 113 atrial electrograms recordings from left-atrial endocardial mapping. These signals were classified by three expert electrophysiologists into four classes, from C0 (non fractionated) to C3 (high degree of fractionation). The calculated features were Approximate entropy, Dispersion entropy, Fuzzy entropy, Permutation entropy, Tsallis entropy, Shannon entropy, Renyi entropy, and Lempel-Ziv complexity. Features were selected for classification using Neighborhood Component Analysis. Different classifiers were tested using selected features, and the one with maximum sensitivity and specificity in each task was reported. ResultsWe obtained a classification performance that overcome previous works on this database and are comparable to the results of studies performed over bigger datasets. Separation between C3 signals from (C0, C1, C2) signals was performed with 99.98% sensitivity and 96.61% specificity. Non-fractionated signals (C0 + C1) were separated from fractionated signals (C2 + C3) with 96.72% sensitivity and 94.51% specificity. Moreover, the estimation times of the selected features are low enough to consider the online application of this scheme. Conclusions and significanceClassification performance obtained using information and complexity measures shown better results than previous works over this dataset, encouraging the application of these features to characterize atrial electrograms.

Chemical mapping as a predictor of vein of Marshall ethanol ablative effects.

The aim of this study was to test regional pharmacological effects of an antiarrhythmic agents to predict ablative effects. The vein of Marshall (VOM) providing vascular access to myocardial tissue has been used for ablative purposes using ethanol. A total of 35 patients (male 21, 63.2±7.8 years old) were included. A balloon-tipped infusion catheter was inserted into the VOM. Endocardial ultrahigh-resolution mapping was performed along the VOM region to record the change in atrial electrograms (AEs) after VOM injection of cibenzoline of 3.5mg during sustained atrial fibrillation (AF). Subsequently, ethanol was infused into the VOM and ablative region was mapped. In 17 patients (49 %), cibenzoline reduced AEs amplitude by>50%, all of which had also complete elimination of AEs following ethanol (Group A). In 18 patients (Group B), cibenzoline failed to eliminate AEs; yet, in 13 of 18 AEs were eliminated by ethanol. In the remaining five patients, ethanol did not eliminate AE. Cibenzoline into the VOM could reliably predicts the results of subsequent ethanol infusion into the VOM using ultrahigh-resolution mapping system, which leads to avoid unnecessary permanent lesion creation by ethanol infusion.

Hybrid Radiofrequency Ablation for a Patient with WPW Syndrome and Complicated Cardiovascular Malformation

Wolff-Parkinson-White (WPW) syndrome causes paroxysmal supraventricular tachycardia (PSVT) and catheter ablation is the most effective therapy method. We summarized a rare case of WPW syndrome. The patient suffered from WPW syndrome complicated with an atrial septal defect (ASD), persistent left superior vena cava, and absence of inferior vena cava. A hybrid operation was arranged to solve his problem. During the procedure, we did endocardial and epicardial mapping and ablation, respectively. Conduction of the accessory pathway could be temporarily obstructed, but recovered soon later. Considering it was a rare and interesting case worth recording and discussing, we share it with the public.

MAGNETIC RESONANCE IMAGING FOR THE DETECTION OF LEFT ATRIAL SCAR: CORRELATION WITH HIGH-DENSITY VOLTAGE MAPPING

There is limited data on the accuracy and reproducibility of cardiac magnetic resonance imaging (CMR) for the detection of left atrial (LA) scar/fibrosis in patients with AF. In this study, we sought to (1) evaluate the presence and extent of left atrial scar detected using delayed enhancement-CMR and to (2) determine the correlation between CMR findings and endocardial voltage mapping-detected LA scar. Patients accepted for catheter ablation for AF were eligible for the study. Delayed enhancement CMR and endocardial voltage mapping for the assessment of LA scar data were both performed during sinus rhythm (requiring cardioversion in most patients). CMR-detected scar was identified as LA regions with tissue-to-blood signal intensity ratio > 1.25 and bipolar voltage < 0.5mV was used to define atrial scar. Scar burden was calculated by dividing the scar area by the total LA area. High-density voltage mapping was acquired using multipolar catheters and a semi-automated software to ensure homogeneous data collection (Confidense module, Biosense Webster, Inc). CMR and endocardial voltage maps were interpreted by blinded to the other investigation result. Forty-five patients were enrolled; LA scar burden assessment with CMR was completed in 43 patients. Two patients were excluded due to poor CMR image quality. Thirty-one patients had persistent and 12 paroxysmal AF. Mean age 64±9 years, LVEF 61±9%. The mean normalized LA volume was 52±17ml/m2. The average number of endocardial points acquired for atrial voltage mapping was 1387±1060. Overall, the correlation for the percentage of atrial scar detected with CMR and endocardial voltage mapping was poor (rho=0.13; 95%CI -0.17 to 0.42; P=0.3). Table1 shows the scar burden by CMR and endocardial voltage map. In this study, the correlation between high-density voltage mapping and CMR-detected atrial scar burden was poor. The overall extent of scar was generally more extensive on CMR when compared to intracardiac mapping. Further research is needed to improve the accuracy of CMR for the detection and quantification of atrial scar in patients with AF.

P5689First intention epicardial VT ablation: what are the results?

Abstract Introduction Ventricular tachycardia (VT) endocardial mapping and ablation may not be sufficient in several arrhythmogenic contexts, because ventricular myocardium may comprise intricate endocardial, intramural and epicardial substract. Thus, epicardial ablation has lately become a complementary and necessary tool to approach some VTs in different types of cardiomyopathies. Purposes To evaluate the clinical characteristics of patient most suitable for first intention epicardial VT ablation and to describe our centre experience. Methods Single-centre prospective study of consecutive patients (pts) undergoing isolated first intention epicardial VT mapping and ablation since August 2015. All pts had clinical assessment, electrocardiogram (ECG), echocardiogram and cardiac magnetic resonance when feasible. Pts with a previous endocardial ablation were excluded. Epicardial subxiphoid access utilizing a tuhoy needle was performed under fluoroscopic guidance. High-density mapping was performed using CARTO® V4 and EnSite PrecisionTM systems and multipolar catheters. Radiofrequency energy was applied with an irrigated-tip catheter. Results First intention epicardial VT ablation was attempted in 12 pts (mean age 57.6±14.6 years, 91% male). The majority had non-ischemic dilated cardiomyopathy, of unknown aetiology in 59%, hereditary dilated cardiomyopathy in 17% ethanolic origin in 8% and post-myocarditis in 8%. Right Ventricular Arrhythmogenic Cardiomyopathy was present in 1 patient. As expected, our population presented a mean ejection fraction of 29% and 11 pts (92%) had an implantable cardioverter defibrillator - ICD (55% as primary prevention, 45% as secondary prevention). All pts had experienced symptomatic VT, with all ICD carriers receiving appropriate shocks. Only 4 pts had an available 12 lead ECG of the VT, and all of them had a QS pattern in lead aVL and a slurred initial QRS complex. The majority of patients presented low voltage areas and local abnormal ventricular activities at the epicardial surface, with the exception of 2 pts in whom ablation was not performed (one non-ischemic cardiomyopathy of ethanolic aetiology and the other of unknown origin). Mean ablation application time was 68 minutes, with an average maximum power of 39.9 watts. Mean overall procedure and fluoroscopic time was 132 and 24 minutes, respectively, with no major intraprocedural complications. During a mean follow-up of 307±328 days, 3 pts died (mean 121 days after procedure), 3 had recurrent VT episodes and ICD shocks, and 2 received heart transplant. Conclusion In selected pts, with non-ischemic dilated cardiomyopathy and ECG with QS pattern in aVL and slurred QRS, epicardial VT mapping and ablation may be used as first approach, preventing unnecessary endocardial mapping. This procedure demonstrated to be safe.

Epicardial Electrical Activation During Atrial Fibrillation: Looking at the Other Side of the Coin

High-definition mapping of atrial fibrillation is most commonly performed from the endocardial surface. This report describes an example of a case in which combined mapping of the endocardium and epicardium of the left atrium demonstrated electrical dissociation between the 2 surfaces and implies that endocardial mapping alone may not provide sufficient information. (Level of Difficulty: Advanced.)

P5702Non-invasive epicardial and endocardial mapping in patients with idiopathic right ventricular outflow tract premature ventricular contractions: new insights into arrhythmia substrate

Abstract Background It has been accepted for years that idiopathic premature ventricular contractions (PVCs) with origin in the right ventricular outflow tract (RVOT) are benign. They are thought to result from triggered activity and most studies do not describe abnormal findings during electroanatomical mapping Dispersion of ventricular repolarization is associated with the susceptibility to ventricular arrhythmias and may indicate the presence of diseased myocardium. The activation recovery interval (ARI) has been used as a surrogate measure of ventricular action potential duration and refractory period. Purpose The aim of this study was to use the new non-invasive epicardial and endocardial mapping system (NEES) to study patients with RVOT PVCs in order to evaluate the ARI in the epicardium of RVOT during sinus rhythm (SR). Methods Non-invasive mapping was performed with the NEES, based on body surface electrocardiograms of a maximum of 224 electrodes and computed tomography imaging data. Unipolar electrograms were reconstructed on the epicardial and endocardial surfaces. Patients were excluded if they had structural heart disease, previous ablation or conduction abnormalities. ARI was defined as the interval between times of minimum derivative of the QRS and the maximum derivative of the T wave in the unipolar electrograms. We evaluated the ARI map in patients with RVOT PVCs and in a control group of patients without PVCs (Figure). We assessed the maximum value of ARI (Max ARI), the minimum value of ARI (Min ARI) and the difference between the Max ARI and the Min ARI (Diff ARI). Results We studied 8 patients with RVOT PVCs and 8 patients without PVCs. The results are presented in the table. Demographic and NEES data RVOT PVCs (n=8) Control (n=8) P value* Demographic data Age in years, median (IQR) 53 (48–65) 59 (52–67) 0.536 Male gender, n (%) 4 (50) 6 (75) 0.608 NEES data Max ARI in msec, median (IQR) 285 (236–331) 228 (197–298) 0.195 Min ARI in msec, median (IQR) 176 (138–192) 216 (185–255) 0.161 ARI diff in msec, median (IQR) 111 (83–147) 15 (4–34) &lt;0.0001 NEES map Conclusion In this group of patients we found a significantly higher dispersion of the ARI measurements through the epicardium of the RVOT in patients with PVCs in comparison with patients without PVCs.

P3687Abnormal voltage recordings in patients with ventricular arrhythmias: comparison between right and left cardiomyopathy

Abstract Background Arrhythmogenic Cardio-Myopathy (ACM) is characterized by epi-endocardial fibro-fatty replacement. Depending on the most affected ventricle, right dominant (RDACM) or left dominant (LDACM) phenotypes can be defined. RDACM voltage mapping characteristics have already been described, with late potentials strongly correlating with arrhythmia recurrence risk; LDACM voltage features have not been described yet. Purpose To analyze voltage map characteristics in LDACM patients (pts) and compare them with RDACM; to assess if there is any correlation between late potentials and recurrence rate in LDACM as well. Methods We retrospectively enrolled all consecutive ACM patients treated c/o our center and diagnosed according to the 2010 Task Force Criteria. Procedural and follow up data were collected. Patient were sorted by ventricular involvement lateralization. Recurrence rates were evaluated and linearly regressed for the presence of late potentials. Results 89 ACM patients were enrolled (67 RDACM, 22 LDACM; 76% males, 69±4 y.o.) in our study. All patients underwent endocardial voltage mapping; procedurally, 43 (48%) pts underwent catheter ablation, while 46 (52%) were managed conservatively with anti-arrhythmic drugs. Bipolar pathological potentials were found in 43 (64%) and 13 (59%), unipolar pathological potentials in 45 (67%) and 14 (63%), while late potentials in 19 (31%) and 8 (36%) in the RDACM and LDACM group respectively [p = 0.66, p=0.63, and p=0.33]. The average follow-up was 18 months [14–48]; 15 (22%) in the RDACM and 9 (40%) in LDACM arrhythmic recurrences were respectively encountered; recurrences in both groups were regressed for the presence of late potentials. Results were as follows: the presence of late potentials correlated with recurrences with an 4,3 [1.15–16.1; p=0.03] OR and with an 11 [0.4–85; p=0.022] OR in the RDACM and LDACM group respectively. Conclusion Pathologically low unipolar, bipolar and late potentials can be found in comparable % both in RDACM and LDACM; like in RDACM, late potentials represent an important risk factor for arrhythmic recurrence in LDACM as well.

Right ventricular outflow tract low-voltage areas identify the site of origin of idiopathic ventricular arrhythmias: A high-density mapping study.

Electronatomical mapping allows direct and accurate visualization of myocardial abnormalities. This study investigated whether high-density endocardial bipolar voltage mapping of the right ventricular outflow tract (RVOT) during sinus rhythm may guide catheter ablation of idiopathic ventricular arrhythmias (VAs). Forty-four patients (18 males, mean age: 38.1 ± 13.8 years) with idiopathic RVOT VAs and negative cardiac magnetic resonance imaging underwent a stepwise mapping approach for the identification of the site of origin (SOO). High-density electronatomical mapping (1096.6 ± 322.3 points) was performed during sinus rhythm and identified at least two low bipolar voltage areas less than 1 mV (mean amplitude of 0.20 ± 0.10 mV) in 39 of 44 patients. The mean low-voltage surface area was 1.4 ± 0.8 cm2 . Group 1 consisted of 28 patients exhibiting low-voltage areas and high-arrhythmia burden during the procedure. Pace match to the clinical VAs was produced in one of these low-voltage areas. Activation mapping established the SOO at these sites in 27 of 28 cases. Group 2 comprised 11 patients exhibiting abnormal electroanatomical mapping, but very low-arrhythmia burden during the procedure. Pace mapping produced a near-perfect or perfect match to the clinical VAs in one of these areas in 9 of 11 patients which was marked as potential SOO and targeted for ablation. During the follow-up period, 25 of 28 patients from group 1 (89%) and 7 of 9 patients from group 2 (78%) were free from VAs. Small but detectable very low-voltage areas during mapping in sinus rhythm characterize the arrhythmogenic substrate of idiopathic RVOT VAs and may guide successful catheter ablation.

Epicardial Conduction Speed, Electrogram Abnormality, and ComputedTomography Attenuation Associations in Arrhythmogenic RightVentricular Cardiomyopathy.

This study sought to evaluate the association between contrast-enhanced multidetector computed tomography (CE-MDCT) attenuation and local epicardial conduction speed (ECS) and electrographic abnormalities in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) and ventricular tachycardia (VT). CE-MDCT is a widely available and fast imaging technology with high spatial resolution that is less prone to defibrillator generator-related safety issues and image artifacts. However, the association between hypoattenuation on MDCT and VT substrates in ARVC remains unknown. Patients with ARVC who underwent CE-MDCT followed by endocardial (n=30) and epicardial (n=21) electroanatomical mapping (EAM) and VT ablation were prospectively enrolled. Right ventricular (RV) mid-myocardial attenuation was calculated from 3-dimensional MDCT images and registered to EAM. Local ECS was calculated by averaging the ECS between each point and 5 adjacent points with concordant wave front direction. A total of 17,311 epicardial and 5,204 endocardial points were included. In multivariable regression analysis clustered by patient, RV myocardial attenuation was associated with epicardial bipolar voltage amplitude (2.5% decrease in amplitude per 10 HU decrease in attenuation; p<0.001), with endocardial unipolar voltage amplitude (0.9% decrease in amplitude per 10 HU decrease in attenuation; p<0.001), and with ECS (0.4% decrease in ECS per 10 HU decrease in attenuation; p=0.001). CE-MDCT attenuation distribution is associated with regional ECS and electrographic amplitude in ARVC. Regions with low attenuation likely reflect fibro-fatty involvement in the RV and may serve as important VT substrates in patients with ARVC who are undergoing VT ablation.

Achieving durable mitral isthmus block: Challenges, pitfalls, and methods of assessment.

Macroreentrant atrial tachycardias often occur following atrial fibrillation ablation, most commonly due to nontransmural lesions in prior ablation lines. Perimitral atrial flutter is one such arrhythmia which requires ablation of the mitral isthmus. Our objectives were to review the literature regarding ablation of the mitral isthmus and to provide our approach for assessment of mitral isthmus block. We review anatomical considerations, ablation strategies, and assessment of conduction block across the mitral isthmus, which is subject to several pitfalls. Activation sequence and spatial differential pacing techniques are discussed for assessment of both endocardial and epicardial bidirectional mitral isthmus block. Traditional methods for verifying mitral isthmus block include spatial differential pacing, activation mapping, and identification of double potentials. Up to 70% of cases require additional ablation in the coronary sinus (CS) to achieve transmural block. Interpretation of transmural block is subject to six pitfalls involving pacing output, differentiation of endocardial left atrial recordings from epicardial CS recordings, identification of a slowly conducting gap in the line, and catheter positioning during spatial differential pacing. Interpretation of unipolar electrograms can identify nontransmural lesions. We employ a combined epicardial and endocardial assessment of mitral isthmus block, which involves using a CS catheter for epicardial recording and a duodecapolar Halo catheter positioned around the mitral annulus for endocardial recording. The assessment of transmural mitral isthmus block can be challenging. Placement of an endocardial mapping catheter around the mitral annulus can provide a precise assessment of conduction across the mitral isthmus.

Noninvasive Mapping of PrematureVentricular Contractions byMerging Magnetocardiography andComputedTomography.

This study aimed to develop a novel premature ventricular contraction (PVC) mapping method to predict PVC origins in whole ventricles by merging a magnetocardiography (MCG) image with a cardiac computed tomography (CT) image. MCG can noninvasively discriminate PVCs originating from the aortic sinus cusp from those originating from the right ventricular outflow tract. This study was composed of 22 candidates referred for catheter ablation of idiopathic PVCs. MCG and CT were performed the same day before ablation. Estimated origins by MCG-CT imaging using the recursive null steering spatial filter algorithm were compared with origins determined by electroanatomic mapping (CARTO, Biosense Webster, Inc., Diamond Bar, California) during the ablation procedure. Radiopaque acrylic markers for the CT scan and coil markers generating a weak magnetic field during MCG measurements were used as reference markers to merge the 2 images 3-dimensionally. PVC origins were determined by endocardial and epicardial mapping and ablation results in 18 (86%) patients (right ventricular outflow tract in 10 patients, aortic sinus cusp in 2 patients, interventricular septum in 1 patient, near His bundle in 1 patient, right ventricular free wall in 1 patient, and left ventricular free wall in 3 patients). Estimated origins by MCG-CT imaging matched the origins determined during the procedure in 94% (17 of 18) of patients, whereas the electrocardiography algorithms were accurate in only 56% (10 of 18). Discrimination of an epicardium versus an endocardium or right- versus left-sided septum was successful in 3 of 4 patients (75%). The diagnostic accuracy of noninvasive MCG-CT mapping was high enough to allow clinical use topredict the site of PVC origins in the whole ventricles.

Случай одномоментного эндокардиального и эпикардиального картирования левого предсердия при выполнении операции «Лабиринт IIIБ»

Случай одномоментного эндокардиального и эпикардиального картирования левого предсердия при выполнении операции «Лабиринт IIIБ»

Evaluation of a real-time magnetic resonance imaging-guided electrophysiology system for structural and electrophysiological ventricular tachycardia substrate assessment.

AimsPotential advantages of real-time magnetic resonance imaging (MRI)-guided electrophysiology (MR-EP) include contemporaneous three-dimensional substrate assessment at the time of intervention, improved procedural guidance, and ablation lesion assessment. We evaluated a novel real-time MR-EP system to perform endocardial voltage mapping and assessment of delayed conduction in a porcine ischaemia–reperfusion model.Methods and resultsSites of low voltage and slow conduction identified using the system were registered and compared to regions of late gadolinium enhancement (LGE) on MRI. The Sorensen–Dice similarity coefficient (DSC) between LGE scar maps and voltage maps was computed on a nodal basis. A total of 445 electrograms were recorded in sinus rhythm (range: 30–186) using the MR-EP system including 138 electrograms from LGE regions. Pacing captured at 103 sites; 47 (45.6%) sites had a stimulus-to-QRS (S-QRS) delay of ≥40 ms. Using conventional (0.5–1.5 mV) bipolar voltage thresholds, the sensitivity and specificity of voltage mapping using the MR-EP system to identify MR-derived LGE was 57% and 96%, respectively. Voltage mapping had a better predictive ability in detecting LGE compared to S-QRS measurements using this system (area under curve: 0.907 vs. 0.840). Using an electrical threshold of 1.5 mV to define abnormal myocardium, the total DSC, scar DSC, and normal myocardium DSC between voltage maps and LGE scar maps was 79.0 ± 6.0%, 35.0 ± 10.1%, and 90.4 ± 8.6%, respectively.ConclusionLow-voltage zones and regions of delayed conduction determined using a real-time MR-EP system are moderately associated with LGE areas identified on MRI.

Assessment of myocardial electrical dissynchrony by noninvasive activation mapping and its role in achieving the success of cardiac resynchronization

To assess and to compare the ventricular myocardium activation patern obtained by non-invasive epi- and endocardial mapping (NIEEM), as well as electrocardiographic (ECG) variants of lef bundle branch block (LBBB) and to estimate the value of these data for the success of cardiac resynchronization therapy (CRT). Te study included 23 patients (mean age 59,6±9,9 years) with LBBB, QRS duration ≥ 130 ms, lef ventricular ejection fraction (LVEF) ≤ 35%, heart failure (HF) NYHA II-IV despite optimal pharmacological therapy during 3 month. All patients had undergone CRT-D implantation. Depending on presence or absence of LBBB ECG-criteria, proposed by Strauss D.G. et. al, patients were divided into 2 groups: 1group - strict LBBB, proposed by Strauss D.G. et. al. (n=14) and 2 group - other ECG morphologies of LBBB (n=9). NIEEM by the Amycard 01C system with an analysis of epi- and endocardial ventricular electrical activation was performed in all patients and 5 healthy volunteers (mean age 29±1,0years). Response to CRT was estimated by echo and was defned as decrease in lef ventricular (LV) end-systolic volume by &gt; 15% afer 6 months of follow-up. LBBB ECG-criteria, proposed by Strauss D.G. et. al, was detected in 14 patients (61% of all included). According to the results of NIEEM, these patients had more pronounced ventricular electrical uncoupling (VEU) (р=0,002). Most ofen the line of block was detected in the anteroseptal or posterolateral region of the LV. Te zone of late LV activation, which is the most optimal position for the LV pacing electrode, was located in the basal and middle segments of the lateral and posterior walls. Afer 6 months of CRT 15 patients (65%) were included in the "response" group, the remaining 8 patients (35%) formed the "non-response" group according to echo criteria. In the "response" group the morphology of the QRS complex more frequently met the criteria, proposed by Strauss D.G. et al, than other ECG variants of LBBB (12 vs. 3 respectively, p = 0.023). Initially, VEU was more pronounced in the "response" group (VEU 55 [51, 64] ms in the "response" group vs 22 [8, 38] ms in the "non-response" group).Сonclusions. LBBB ECG criteria, proposed by Strauss D.G., identify patients with delayed transseptal interventricular conduction due to complete LBBB, what is a good target for CPT. Identifcation of individual ventricular activation properties may help to reveal responders to CRT in patients with LBBB.