Anders Sommer

Multimodality imaging-guided left ventricular lead placement in cardiac resynchronization therapy: a randomized controlled trial.

Left ventricular (LV) lead position at the latest mechanically activated non‐scarred myocardial LV region confers improved response to cardiac resynchronization therapy (CRT). We conducted a double‐blind, randomized controlled trial to evaluate the clinical benefit of multimodality imaging‐guided LV lead placement in CRT.

Left and right ventricular lead positions are imprecisely determined by fluoroscopy in cardiac resynchronization therapy: a comparison with cardiac computed tomography

AIMS Fluoroscopy is the routine method for localizing left ventricular (LV) and right ventricular (RV) lead positions in cardiac resynchronization therapy (CRT). However, the ability of fluoroscopy to determine lead positions in a standard ventricular segmentation is unknown. We aimed to evaluate the accuracy and reproducibility of fluoroscopy to determine LV and RV lead positions in CRT when compared with cardiac computed tomography (CT). METHODS AND RESULTS Fifty-nine patients undergoing CRT were included. Bi-plane fluoroscopy and cardiac CT were evaluated in all patients. Pacing lead positions were assessed in a standard LV 16-segment model and in a simplistic RV 8-segment model. Four patients with LV lead displacement were excluded from the agreement analysis of LV lead position. Agreement of LV lead position between fluoroscopy and cardiac CT was observed in 19 (35%) patients with fluoroscopy demonstrating a 1-segment and ≥2-segment error in 30 (55%) and 6 (11%) patients, respectively. Agreement of RV lead position was found in 13 (22%) patients with fluoroscopy showing a 1-segment and ≥ 2-segment error in 28 (47%) and 18 (31%) patients, respectively. The interobserver agreement on LV and RV lead positions was poor for fluoroscopy (kappa 0.20 and 0.23, respectively) and excellent for cardiac CT (kappa 0.87 and 0.85, respectively). CONCLUSION Fluoroscopy is inaccurate and modestly reproducible when assessing LV and RV lead positions in a standard ventricular segmentation when compared with cardiac CT. Cardiac CT should be applied to determine the exact pacing site in future research evaluating the optimal pacing lead position in CRT.

Empiric versus imaging guided left ventricular lead placement in cardiac resynchronization therapy (ImagingCRT): study protocol for a randomized controlled trial.

BackgroundCardiac resynchronization therapy (CRT) is an established treatment in heart failure patients. However, a large proportion of patients remain nonresponsive to this pacing strategy. Left ventricular (LV) lead position is one of the main determinants of response to CRT. This study aims to clarify whether multimodality imaging guided LV lead placement improves clinical outcome after CRT.Methods/DesignThe ImagingCRT study is a prospective, randomized, patient- and assessor-blinded, two-armed trial. The study is designed to investigate the effect of imaging guided left ventricular lead positioning on a clinical composite primary endpoint comprising all-cause mortality, hospitalization for heart failure, or unchanged or worsened functional capacity (no improvement in New York Heart Association class and <10% improvement in six-minute-walk test). Imaging guided LV lead positioning is targeted to the latest activated non-scarred myocardial region by speckle tracking echocardiography, single-photon emission computed tomography, and cardiac computed tomography. Secondary endpoints include changes in LV dimensions, ejection fraction and dyssynchrony. A total of 192 patients are included in the study.DiscussionDespite tremendous advances in knowledge with CRT, the proportion of patients not responding to this treatment has remained stable since the introduction of CRT. ImagingCRT is a prospective, randomized study assessing the clinical and echocardiographic effect of multimodality imaging guided LV lead placement in CRT. The results are expected to make an important contribution in the pursuit of increasing response rate to CRT.Trial registrationClinicaltrials.gov identifier NCT01323686. The trial was registered March 25, 2011 and the first study subject was randomized April 11, 2011.

Left ventricular longitudinal systolic function after alcohol septal ablation for hypertrophic obstructive cardiomyopathy: a long-term follow-up study focused on speckle tracking echocardiography

AIMS To examine left ventricular (LV) longitudinal systolic myocardial function in patients with hypertrophic obstructive cardiomyopathy (HOCM) before and after transcoronary ablation of septal hypertrophy (TASH). METHODS AND RESULTS Twenty-three of 39 consecutive patients with HOCM had serial two-dimensional (2D) echocardiograms available for speckle tracking analyses before and up to 36 months after TASH. Before TASH, overall LV myocardial longitudinal systolic 2D strain was decreased despite normal LV ejection fraction (EF). A significant reduction of LV mass and left ventricular outflow tract (LVOT) gradients occurred during long-term follow-up after TASH, but this was not accompanied by improvement of average LV longitudinal systolic strain. However, in the basal LV segments remote to the site of alcohol injection longitudinal systolic strain increased [baseline: -13.1 ± 5.4%; 1 month: -16.0 ± 5.5% (NS); 12 months: -16.5 ± 4.9% (P < 0.05 vs. baseline); 36 months: -17.4 ± 4.2% (P < 0.01 vs. baseline)]. In contrast, the alcohol-treated basal segments of the septum and adjacent myocardium showed unchanged strain over time. CONCLUSION Average LV longitudinal myocardial systolic function is depressed in HOCM despite normal LV EF. TASH-induced reduction of the LVOT obstruction does not improve average LV longitudinal systolic 2D strain. This is in contrast to global improvement of longitudinal systolic function after valve replacement in aortic valve stenosis. The discrepancy may be caused by the fact that HOCM is a primary myocardial disease.

The paced electrocardiogram cannot be used to identify left and right ventricular pacing sites in cardiac resynchronization therapy: validation by cardiac computed tomography

AIMS Paced electrocardiogram characteristics to confirm left ventricular (LV) and right ventricular (RV) pacing sites in cardiac resynchronization therapy (CRT) have not been validated with accurate knowledge of pacing lead positions. We aimed to evaluate the ability of the paced QRS morphology to differentiate between various LV and RV lead positions using cardiac computed tomography (CT) as the reference for LV and RV pacing site. METHODS AND RESULTS Ninety-seven CRT patients were included. The QRS morphology was evaluated during forced LV-only and RV-only pacing. Pacing lead positions were assessed in a standard LV 16-segment model and a simplistic RV 6-segment model using cardiac CT. Ten patients with LV lead displacement or a LV pacing site outside the non-apical free wall were excluded from the analysis of the LV paced QRS complex. Pacing within the LV free wall was associated with a superior and a right-axis deviation (P = 0.02 and 0.04, respectively). Pacing from basal LV segments mainly produced a late (V5 or later) precordial QRS transition as compared with mid-LV pacing (P = 0.001). No significant associations were found between RV pacing site and QRS axis or precordial transition. Different QRS morphologies were observed during single-chamber pacing from identical LV or RV myocardial segments. CONCLUSION Weak associations exist between LV and RV pacing sites and the paced QRS axis. None of the paced QRS characteristics can be used to reliably confirm specific LV and RV pacing sites in CRT patients.

Left ventricular regional remodeling and lead position during cardiac resynchronization therapy

BACKGROUND Cardiac resynchronization therapy (CRT) induces segmental left ventricular (LV) remodeling. The LV lead position (LV-LP) affects response to CRT and remodeling. OBJECTIVE We aimed to assess segmental remodeling concordant, adjacent, and remote to LV-LP using cardiac computed tomography (CT). METHODS We included patients from the Empiric Versus Imaging-Guided Left Ventricular Lead Placement in Cardiac Resynchronization Therapy trial. Dynamic cardiac CT was performed at baseline and after 6 months. We assessed systolic wall thickening (WT) and exact LV-LP from the CT scans according to a 16-segment model. Response to CRT was defined as ≥15% reduction in LV end-systolic volume. RESULTS A total of 107 consecutive patients were included. The change in WT from baseline to follow-up was -19% (95% confidence interval [CI] -25% to -13%; P < .001) in concordant segments, -0.1% (95% CI -5% to 5%; P = .97) in adjacent segments, and 20% (95% CI -17% to 23%; P < .001) in remote segments. Diastolic wall thickness changed only marginally. Twenty patients (19%) were nonresponders at follow-up. In nonresponders with nonischemic cardiomyopathy, we observed a significant reduction in WT in concordant and adjacent segments with no increase in WT in remote segments. CONCLUSION During CRT, systolic WT increases in segments remote to LV-LP, decreases in concordant segments, and remains unchanged in adjacent segments. Only marginal changes occur in wall thickness. In nonresponders with nonischemic cardiomyopathy, deleterious changes in segmental myocardial function occur, and further studies on how to treat these patients best are warranted.

Longer inter-lead electrical delay is associated with response to cardiac resynchronization therapy in patients with presumed optimal left ventricular lead position

Aims In a randomized trial of cardiac resynchronization therapy (CRT), a presumed optimal left ventricular (LV) lead position close to the latest mechanically activated non-scarred myocardium was achieved in 98% of patients by standard implantation. We evaluated whether inter-lead electrical delay (IED) was associated with response to CRT in these patients. Methods and results We prospectively included 160 consecutive patients undergoing CRT. Pre-implant speckle-tracking echocardiography radial strain and 99mTc myocardial perfusion imaging determined the latest mechanically activated non-scarred myocardial segment. We measured procedural IED as the time interval between sensed signals in right ventricular and LV lead electrograms. All patients had LV pacing site concordant or adjacent to the latest mechanically activated non-scarred segment verified by cardiac computed tomography. Response to CRT was defined as ≥15% reduction in LV end-systolic volume at 6 months follow-up. Selecting a practical IED cut-off value of 100 ms, more patients with long IED than patients with short IED responded to CRT (87 vs. 68%; P = 0.004). In multivariate logistic regression analysis, IED ≥100 ms remained associated with CRT response after adjusting for baseline characteristics, including QRS duration and scar burden [odds ratio 3.19 (1.24-8.17); P = 0.01]. Categorizing IED by tertiles, CRT response improved with longer IED (P = 0.03). Comparable response rates were observed in patients with a concordant and adjacent LV lead position. Conclusion A longer IED was associated with more pronounced LV reverse remodelling response in CRT recipients with a presumed optimal LV lead position concordant or adjacent to the latest mechanically activated non-scarred segment.

Guided left ventricular lead placement for cardiac resynchronization therapy - an opportunity for image integration: reply

Dr Behar, Dr Rajani, and Dr Rinaldi are thanked for their interest in our recent trial evaluating the clinical benefit of multimodality imaging-guided left ventricular (LV) lead placement in cardiac resynchronization therapy (CRT).1,2 We acknowledge the potential of image integration for improving the precision of LV lead positioning towards a predefined optimal LV pacing site. A validated accurate algorithm for fusion of procedural fluoroscopic venography with pre-implant imaging is required to benefit from such a strategy. Preferably, a pre-implant ‘all-in-one’ imaging modality (e.g. cardiac magnetic resonance imaging) for visualizing myocardial scar, mechanical activation pattern, and cardiac venous anatomy should be performed and accurately integrated with the procedural venography to target the desired level of the optimal cardiac vein. The potential clinical benefit of such an approach remains to be evaluated in a prospective randomized setting. Previous trials investigating the impact of imaging-guided LV lead placement on CRT outcome applied fluoroscopy to guide lead position towards a predefined optimal segment for LV pacing as determined by .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. echocardiography.3,4 Designing the present trial, we acknowledged the inaccuracy and poor reproducibility of fluoroscopy to determine lead position in heart failure patients.5 Accordingly, we performed a pre-implant cardiac computed tomography (CT) to visualize the anatomical relation between available cardiac veins and underlying LV myocardium. Moreover, a three-dimensional reconstruction of cardiac venous anatomy could easily be co-registered with the procedural fluoroscopic venography to identify and target the optimal cardiac vein closest to the predefined optimal myocardial segment for LV pacing. Furthermore, cardiac CT verified final LV lead position according to the myocardial segmentation including relation to the optimal pacing site and pre-implant visualized cardiac veins.1 A LV lead location concordant or adjacent to optimal pacing site is generally considered ideal as reaching a concordant position is constrained by cardiac venous anatomy, lead stability, pacing threshold, and phrenic nerve stimulation. The present trial supports the use of an imaging-guided strategy for LV lead placement. Nevertheless, challenging the need for imaging-guided LV lead positioning, our control group routine approach targeting the LV lead towards a non-apical posterolateral region with late electrical activation resulted in a lead position concordant or adjacent to the optimal pacing site in the vast majority (98%) of patients. Accordingly, other strategies for optimizing LV lead positioning should be investigated. The alternative individualized strategy for LV lead placement, without the need for pre-implant imaging, targeting the region with .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. latest electrical activation needs prospective evaluation.6