PMC5412653_01
Data in case 1. A and G: 12-lead electrocardiograms before and after the cardiac resynchronization therapy (CRT), respectively. The QRS duration of 164 milliseconds before the implantation shortened to 140 milliseconds during CRT. B and H: 2-dimensional speckle tracking-derived displacement curves of right ventricle (RV) and septal segments in an apical 4-chamber view before and after the implantation, respectively. Positive and negative values indicate the location of each sample relative to baseline, inside and outside the RV cavity. Red and green dotted arrows indicate negative peak of the curves of RV free wall (RVFW) and apical septal wall (SEP), respectively. Contraction delay of RVFW relative to the SEP (indicated by horizontal bidirectional arrows) was 228 milliseconds, whereas the delay was improved by 72 milliseconds after CRT. C and D: Activation maps of the RV septum and RVFW, respectively, during sinus rhythm with right bundle branch block (RBBB) in a right anterior oblique view. Left-to-right transseptal wavefront breakthrough from the RV midseptum, with propagation to the basal lateral wall with a delay of 129 milliseconds, compared with that of the RV septal wall. E and F: Fluoroscopic views in left and right oblique projections showing lead positions. I and J: Abdominal computed tomography before and after the implantation, respectively. CS = coronary sinus, RA = right atrium, RVA = RV apex.
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A 12-lead electrocardiogram (ECG) during sinus rhythm showed complete RBBB and prolonged PQ interval of 250 milliseconds (Figure 1A). A transthoracic echocardiogram revealed preserved left ventricular (LV) size and an ejection fraction of 63% with paradoxical septal motion, but a moderate or severe impairment of RV contractile function (Table 1), and marked conduction delay of the RV free wall compared with that of the septal wall, consistent with mechanical dyssynchrony in the RV (Figure 1B). RV during sinus rhythm made by using a CARTO XP 3-dimensional electroanatomic mapping system (Biosense Webster, Diamond Bar, CA) also demonstrated the conduction delay of the RV basal lateral wall compared with that of the septal wall, consistent with electrical dyssynchrony in the RV (Figures 1C and 1D). Right heart catheterization revealed an RV pressure of 42/17/31 mm Hg (systolic/diastolic/end-diastolic) with a dip and plateau pattern, a mean right atrial (RA) pressure of 26 mm Hg, and a pulmonary capillary wedge pressure of 20 mm Hg. Consulta CRT-P C3TR01 device (Medtronic, Minneapolis, MN) (Figure 1E and 1F). CRT was achieved by atrial synchronous, simultaneous biventricular multifocal pacing with sensed atrioventricular delay of 100 milliseconds, resulting in a shortening of the QRS width (Figure 1G) An echocardiogram showed normalization of RV dyssynchrony (Figure 1H) and improvement of RV contractile function (Table 1). Compared with massive ascites before the CRT-RV, obviously decreased ascites showed in the results of follow-up computed tomography (Figures 1I and 1J).
PMC5412653_02
Data in case 2. A and E: 12-lead electrocardiograms before and after the implantation, respectively. QRS duration shortened from 194 to 172 milliseconds after the CRT. B and F: 2-dimensional speckle tracking-derived displacement curves of RV and septal segments in an apical 4-chamber view before and after the CRT, respectively. Red and blue dotted arrows indicate the negative peaks of the curves of the RVFW and mid SEP, respectively. The contraction delay of RVFW relative to the SEP was markedly improved from 259 to 0 milliseconds. C and D: Fluoroscopic views in left and right oblique projections showing lead positions. Other abbreviations are as in Figure 1.
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On the patient's admission to the hospital, a 12-lead ECG showed RV paced rhythm with atrial fibrillation (Figure 2A). The analysis of longitudinal strain with 2-dimensional speckle tracking demonstrated RV dyssynchrony (Figure 2B). Paul, MN) (Figures 2C and 2D). CRT was achieved by atrial asynchronous, simultaneous biventricular multifocal pacing, resulting in a shortening of QRS width (Figure 2E). A follow-up echocardiogram demonstrated an improvement in RV dyssynchrony (Figure 2F).