Residual Dyssynchrony Research Articles

Characterization of non-response to cardiac resynchronization therapy by post-procedural computed tomography.

Causes of non-response to cardiac resynchronization therapy (CRT) include mechanical dyssynchrony, myocardial scar, and suboptimal left ventricular (LV) lead location. We aimed to assess the utility of Late Iodine Enhancement Computed Tomography (LIE-CT) with image subtraction in characterizing CRT non-response. CRT response was defined as a decrease in LV end-systolic volume>15% at 6 months. LIE-CT was performed after 6 months, and analyzed global and segmental dyssynchrony, myocardial scar, coronary venous anatomy, and position of LV lead relative to scar and segment of latest mechanical contraction. We evaluated 29 patients (age 71 ± 12 years; 72% men) including 18 (62%) responders. All metrics evaluating residual dyssynchrony such as wall motion index and wall thickness index were worse in non-responders. There was no difference in presence and extent of scar between responders and non-responders. However, in non-responders, the LV lead was more often over an akinetic/dyskinetic area (72% vs. 22%, p=.007), a fibrotic area (64%vs. 8%, p=.0007), an area with myocardial thickness<6mm (82%vs. 22%, p=.002), and less often concordant with the region of maximal wall thickness (9%vs. 72%, p=.001). Among the 11 non-responders, eight had at least another coronary venous branch visualized by CT, including three (27%) coursing over a potentially interesting myocardial area (free of scar, with normal wall motion, and with a myocardial thickness ≥6mm). LIE-CT with image subtraction allows a comprehensive characterization of patients after CRT and may provide clues for management of non-responders.

Utility of Late Iodine Enhancement computed tomography with image subtraction in the evaluation of Cardiac Resynchronization Therapy response (ULIE-CRT study)

Thirty percent of patients fail to respond to cardiac resynchronization therapy (CRT). The evaluation of left ventricular (LV) dyssynchrony, myocardial scar, and coronary venous anatomy by image subtraction in Late Iodine Enhancement Computed Tomography (LIE-CT) has the potential to comprehensively characterize non- responders. To assess the feasibility and the utility of image subtraction in LIE-CT in CRT patients and compare findings between responders and non-responders. Monocentric prospective study of CRT patients at least 6 months after implantation who underwent post-procedural CT between March and October 2018. CRT-responders were defined as patients with an absolute increase in LV ejection fraction > 5 %. CT-derived residual global and segmental dyssynchrony metrics, extent and location of myocardial scar, and position of LV lead relative to scar and segment of latest mechanical contraction were analyzed. Among the 29 patients (mean age 71 ± 12 years; 72% men), 18 were responders (62%). All CT metrics evaluating residual dyssynchrony such as wall motion index and wall thickness index were worse in non- responders ( P < 0.0001 for both). In LIE-CT, predictive factors of CRT-non-response were an LV lead localized in a region of myocardial scar ( P = 0.0007), in a region with akinesia or dyskinesia ( P = 0.007), and with myocardial thickness < 6 mm ( P = 0.002). Percentage of fibrosis of the myocardial mass and the presence of fibrosis in postero-lateral region were not predictive of CRT-non-response late iodine computed with image ( P = 0.9 and P = 0.3, respectively) ( Fig. 1 ). Image subtraction in LIE-CT in patients who had CRT is feasible and allows better characterization of CRT-non-responders, who have a greater amount of residual dyssynchrony than responders. Distribution of fibrosis in relation to the LV lead and presence of alternative venous branches may help patient management.

P5679Utility of late iodine enhancement computed tomography with image subtraction in the evaluation of cardiac resynchronization therapy response

Abstract Background Despite the impressive results of the large CRT trials, it has been observed that, on an individual basis, about 30% of patients fail to respond to cardiac resynchronization therapy (CRT). The evaluation of left ventricular (LV) dyssynchrony, myocardial scar, and coronary venous anatomy by image subtraction in Late Iodine Enhancement Computed Tomography (LIE-CT) has the potential to comprehensively characterize non-responders. Purpose To assess the feasibility and the utility of image subtraction in LIE-CT in CRT patients and compare findings between responders and non-responders. Methods Monocentric prospective study of CRT patients at least 6 months after implantation who underwent post-procedural CT between March and October 2018. CRT-responders were defined as patients with an absolute increase in LV ejection fraction &gt;5%. CT-derived residual global and segmental dyssynchrony metrics, extent and location of myocardial scar, coronary venous anatomy, and position of LV lead relative to scar and segment of latest mechanical contraction were analyzed. Results Among the 29 patients (mean age 71±12 years; 72% men), 18 were responders (62%). All CT metrics evaluating residual dyssynchrony such as wall motion indexand wall thickness indexwere worse in non-responders (p&lt;0.0001 for both). In LIE-CT, predictive factors of CRT-non-response were an LV lead localized in an region of myocardial scar (p=0.0007), in a region with akinesia or dyskinesia (p=0.007), and with myocardial thickness &lt;6mm (p=0.002). Percentage of fibrosis of the myocardial mass and the presence of fibrosis in postero-lateral region were not predictive of CRT-non-response (p=0.9 and p=0.3, respectively). Of the 11 non-responder patients, 8 (73%) had at least one other coronary venous branch visualized by CT; and among those, 3 (38%) were located in an non-akinetic area with late segmental contraction. Wall Motion and LIE-CT Conclusion Image subtraction in LIE-CT in patients who had CRT is feasible and allows better characterization of CRT-non-responders, who have a greater amount of residual dyssynchrony than responders. Distribution of fibrosis in relation to the LV lead and presence of alternative venous branches may help patient management.

Triple-site pacing: a new supported therapy approach for bridge to recovery with a left ventricular assist system in a patient with idiopathic dilated cardiomyopathy

Left ventricular assist devices (LVAD) are widely used as bridges to cardiac transplantation or for destination therapy. LVAD support may also function as a bridge to ventricular recovery, but a sufficient rate of recovery has not been obtained, even with various adjuvant therapies. Cardiac resynchronization therapy (CRT) is an effective treatment for heart failure, and there is a report of successful weaning off LVAD with CRT. However, some patients with CRT could not improve their cardiac function because of residual dyssynchrony. Herein, we describe a case of a successful bridge to recovery with triple-site pacing for residual dyssynchrony after biventricular pacing. A 34-year-old woman with heart failure due to dilated cardiomyopathy whose condition deteriorated underwent Toyobo LVAD implantation, resulting in improvement of the left ventricular ejection fraction (LVEF) from 12 to 36%. Because of left ventricular dyssynchrony, we performed CRT, but residual dyssynchrony impeded cardiac recovery. We inserted an additional ventricular lead at the right ventricular outlet to achieve triple-site pacing in order to obtain complete synchronization. The LVEF improved to 45%, and the patient was successfully weaned off the LVAD. In LVAD-supported cases of persistent left ventricular dyssynchrony with CRT, implantation of triple-site pacing could potentially accelerate recovery.

Echocardiographic Aspects of Multisite Pacing in Patients Undergoing Cardiac Resynchronization Therapy

Echocardiography has emerged as an accepted approach to define dyssynchrony in patients with advanced stage of heart failure (HF). Unfortunately no single echocardiographic parameter has been established to predict positive response after cardiac resynchronization therapy (CRT) and the nonresponder rate of 20-30% is still a matter of discussion and research. One of the most promising techniques in this regard is two-dimensional strain echocardiography based on speckle tracking with the potential to disclose residual dyssynchrony after primary CRT. An important reason for weak response to CRT is suboptimal position of the coronary sinus (CS) lead. Initial clinical benefit after CRT may mask partial residual dyssynchrony, which may cause worsening and recurrence of HF symptoms over time. Echocardiography helps to define the location of residual dyssynchrony and may identify patients who would benefit from implantation of a second CS-lead and triple-site pacing. If primary CRT fails due to imperfect placement of the CS-lead or due to coronary vein abnormalities and an epicardial approach is not appropriate, dual site pacing of the right ventricle may be an alternative procedure.

Significance of morphological and electrophysiological left ventricular restoration in idiopathic dilated cardiomyopathy

Treatment of non-ischemic dilated cardiomyopathy (NIDCM) remains a challenge. Morphological left ventricular (LV) restoration such as septal anterior ventricular exclusion (SAVE) can be effective in treating NIDCM; however, residual electrophysiological disorders such as atrioventricular and intraventricular conduction disturbances become apparent in the form of atrial fibrillation (AF) and LV dyssynchrony, which deteriorate postoperative LV function. Thus, the combination of morphological and electrophysiological LV restoration may further improve LV function. Here, we report the case of a patient with end-stage NIDCM complicated with AF and LV dyssynchrony, who was successfully treated with the combined use of SAVE, undersized mitral annuloplasty, left atrial (LA) Maze procedure with cryoablation, and postoperative biventricular pacing. This combination treatment was beneficial in restoring the sinus rhythm and LA and LV functions with improved and synergic wall motion by excluding the dyskinetic/akinetic area, downsizing the LV, resolving mitral regurgitation, and optimizing conduction and rhythm abnormalities. Notably, biventricular pacing was shown to be effective in resolving residual dyssynchrony between the septum and lateral wall after SAVE, wherein a firm, non-compliant Dacron patch was sutured to the septum.