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Background: Pacemapping (PM) is a useful maneuver for aiding premature ventricular complex (PVC) ablation. Its standalone clinical value is still to be defined., Objectives: The purpose of this study was to analyze the efficacy of a predefined PM protocol for low-burden PVC ablation, regardless of their site of origin (SOO) and the presence of structural heart disease., Methods: This was a prospective, nonrandomized, multicenter study. The PM protocol was performed when <1 PVC/min was found. The "target area" was delimited by the 3 best matching points >94% correlation, and 3 radiofreqency (RF) applications were delivered., Results: Of 185 patients, 105 (57%) underwent activation mapping, 60 (32%) were PM-guided, and 20 (11%) were canceled due to absence of PVCs. Baseline QRS, PVC burden, and outflow tract origin were independent predictors of PM-guided ablation. A higher proportion of right ventricular outflow tract SOO in the PM group (52% vs 40%; P = .03) was observed. Mean target area was 0.6 ± 0.9 cm 2 . Mean 10-ms isochronal area in local activation time (LAT)-guided procedures was higher (1.7 ± 2.3 cm 2 ; P <.001). Mean number of PM matching points acquired was 39 ± 21 (range 6-98). Mean mapping and RF times were similar in both groups. However, significantly shorter procedural (53 ± 24 vs 61 ± 26 minutes; P = .04) as well as RF times (111 ± 51 vs 149 ± 149 seconds; P = .05) were needed in the PM group using the proposed protocol. Global clinical success reached 87% for the PM group and 90% (P = .58) the for LAT mapping group., Conclusion: When LAT mapping is precluded, application of a PM-guided ablation protocol directed to >94% matching correlation target area is a more efficient alternative with comparable clinical results., (Copyright © 2021. Published by Elsevier Inc.)

Background: Frequent premature ventricular complexes (PVCs) are common after a myocardial infarction (MI), but data on PVC ablation in this population are limited., Objective: The purpose of this study was to analyze data on PVC ablation in post-MI patients., Methods: Three hundred thirty-two patients with frequent PVCs and left ventricular (LV) dysfunction were prospectively studied. Data from 67 patients (20%; age 63 ± 10 years; 65 men [93%]) with previous MI were compared with the remaining 265 patients., Results: PVCs in post-MI patients originate predominantly from the LV (92% LV vs 6% right ventricle [RV]; P <.001). The most frequent sites of origin (SOO) were MI scar in 23 patients (34%) and left ventricular outflow tract (LVOT) in 22 patients (33%). A papillary muscle origin was more frequent in post-MI patients (16% vs 4%; P = .001), whereas an RV outflow tract origin was less frequent (1% vs 33%; P <.001) compared to patients without MI. In post-MI patients, PVC burden decreased from 29% ± 12% at baseline to 4.6% ± 7% (P <.001); left ventricular ejection fraction (LVEF) improved from 33.6% ± 8% to 42% ± 10% (P <.001); and New York Heart Association functional class improved from 2.1 ± 0.7 to 1.4 ± 0.5 points (P <.001) at 12 months. Compared with the remaining 265 patients, there were no differences in acute ablation success (85% vs 85%; P = .45), complication rate (6% vs 6%; P = .41), or absolute improvement in LVEF (8.8 ± 10 vs 9.9 ± 11 absolute points; P = .38)., Conclusion: PVC ablation significantly improves cardiac function and functional status in post-MI patients. PVCs predominantly originate from MI scar and LVOT. A papillary muscle SOO was found to be strongly associated with previous MI., (Copyright © 2020 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

This paper presents a new registration algorithm, called Temporal Diffeomorphic Free Form Deformation (TDFFD), and its application to motion and strain quantification from a sequence of 3D ultrasound (US) images. The originality of our approach resides in enforcing time consistency by representing the 4D velocity field as the sum of continuous spatiotemporal B-Spline kernels. The spatiotemporal displacement field is then recovered through forward Eulerian integration of the non-stationary velocity field. The strain tensor is computed locally using the spatial derivatives of the reconstructed displacement field. The energy functional considered in this paper weighs two terms: the image similarity and a regularization term. The image similarity metric is the sum of squared differences between the intensities of each frame and a reference one. Any frame in the sequence can be chosen as reference. The regularization term is based on the incompressibility of myocardial tissue. TDFFD was compared to pairwise 3D FFD and 3D+t FFD, both on displacement and velocity fields, on a set of synthetic 3D US images with different noise levels. TDFFD showed increased robustness to noise compared to these two state-of-the-art algorithms. TDFFD also proved to be more resistant to a reduced temporal resolution when decimating this synthetic sequence. Finally, this synthetic dataset was used to determine optimal settings of the TDFFD algorithm. Subsequently, TDFFD was applied to a database of cardiac 3D US images of the left ventricle acquired from 9 healthy volunteers and 13 patients treated by Cardiac Resynchronization Therapy (CRT). On healthy cases, uniform strain patterns were observed over all myocardial segments, as physiologically expected. On all CRT patients, the improvement in synchrony of regional longitudinal strain correlated with CRT clinical outcome as quantified by the reduction of end-systolic left ventricular volume at follow-up (6 and 12months), showing the potential of the proposed algorithm for the assessment of CRT., (Copyright © 2011 Elsevier B.V. All rights reserved.)

In this paper, we present a new method for the automatic comparison of myocardial motion patterns and the characterization of their degree of abnormality, based on a statistical atlas of motion built from a reference healthy population. Our main contribution is the computation of atlas-based indexes that quantify the abnormality in the motion of a given subject against a reference population, at every location in time and space. The critical computational cost inherent to the construction of an atlas is highly reduced by the definition of myocardial velocities under a small displacements hypothesis. The indexes we propose are of notable interest for the assessment of anomalies in cardiac mobility and synchronicity when applied, for instance, to candidate selection for cardiac resynchronization therapy (CRT). We built an atlas of normality using 2D ultrasound cardiac sequences from 21 healthy volunteers, to which we compared 14 CRT candidates with left ventricular dyssynchrony (LVDYS). We illustrate the potential of our approach in characterizing septal flash, a specific motion pattern related to LVDYS and recently introduced as a very good predictor of response to CRT., (Copyright © 2010 Elsevier B.V. All rights reserved.)

Background: Right ventricular apex pacing for gradient reduction in hypertrophic obstructive cardiomyopathy (HOCM) with severe left ventricular (LV) obstruction has yielded conflicting results., Objective: The purpose of this study was to assess the feasibility and effectiveness of biventricular pacing in HOCM., Methods: Transvenous biventricular pacing was attempted in 12 severely symptomatic HOCM patients. Optimal intervals were programmed after implant. Echocardiographic LV pressure gradient and synchrony were assessed. LV lead implantation was successful in 9 patients. Optimal pacing mode was biventricular in 6 patients, left ventricular only in 2 patients, and right ventricular only in 1 patient., Results: Functional capacity and quality of life progressively improved. New York Heart Association functional class decreased from 3.2 ± 0.4 at baseline to 1.9 ± 0.3 at 3 months and to 1.4 ± 0.5 at 1 year (P <.05); 6-minute walk test increased from 349 ± 116 m at baseline to 454 ± 144 m at 3 months and to 517 ± 206 m (P <.05); and quality of life increased from 54 ± 16 points at baseline to 28 ± 13 points at 3 months and 27 ± 15 points at 1 year (P <.05). There was also a progressive reduction in LV gradient from 74 ± 23 mmHg at baseline to 50 ± 27 mmHg acutely, 40 ± 26 mmHg at 3 months, and 28 ± 17 mmHg at 1 year (P <.05). Gradient reduction was associated with diminished peak longitudinal displacement of the LV septum and earlier displacement of the lateral wall. A progressive reduction of LV mass was observed, from 356 ± 110 g at baseline to 315 ± 70 g at 3 months (P = .13) and to 284 ± 42 g at 1 year (P <.05)., Conclusion: Biventricular pacing is feasible and usually the best configuration for gradient reduction in HOCM. Biventricular pacing reduces LV hypertrophy., (Copyright © 2011 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Analysis of myocardial strain using two-dimensional (2D) echocardiography to assess left ventricular (LV) mechanical dyssynchrony by measuring time differences in peak systolic strains from opposing LV walls has been proposed. However, peak systolic strain may be difficult to identify., Objective: The purpose of this study was to evaluate (1) LV dyssynchrony by assessing the overlap among strain traces of the LV walls throughout the cardiac cycle and (2) its usefulness in identifying responders to cardiac resynchronization therapy (CRT)., Methods: Fifty patients with heart failure and LV systolic dysfunction undergoing CRT were studied with 2D echocardiography at baseline and 6-month follow-up. Myocardial radial strain and circumferential strain were analyzed using commercially available software. The resulting strain traces were postprocessed with a mathematical script., Results: Quantification of LV dyssynchrony was expressed as an index of temporal overlap from the analyzed traces. Responders to CRT were defined by ≥15% reduction of LV end-systolic volume at 6-month follow-up. Responders to CRT had higher LV dyssynchrony in both radial strain and circumferential strain analysis. A cutoff time overlap ≥7% for radial strain (area under the curve 0.79) and ≥8.5% for circumferential strain (area under the curve 0.66) identified responders to CRT., Conclusion: Quantifying the temporal superposition of LV wall deformations with a computed algorithm allows measurement of LV intraventricular dyssynchrony throughout the cardiac cycle. The derived index is useful in stratifying the probability of response to CRT., (Copyright © 2010 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)