Not left ventricular lead position, but the extent of immediate asynchrony reduction predicts long-term response to cardiac resynchronization therapy

Feasibility of Left Ventricle Lead Implantation in Cardiac Resynchronization Therapy Guided by Gated SPECT and Ventricular Remodeling

BACKGROUND

Cardiac resynchronization therapy (CRT) may benefit patients with advanced heart failure (HF). Abnormal eccentricity index by gated SPECT is related to structural and functional alterations of the left ventricle (LV).

OBJECTIVE

The aim of this study is to evaluate the feasibility of LV lead implantation guided by phase analysis and its relationship to ventricular remodeling.

METHODS

Eighteen patients with indication for CRT underwent myocardial scintigraphy for implant orientation, and eccentricity and ventricular shape parameters were evaluated. P < 0.05 was adopted as statistical significance.

RESULTS

At baseline, most patients were classified as NYHA 3 (n = 12). After CRT, 11 out of 18 patients were reclassified to a lower degree of functional limitation. In addition, patients' quality of life was improved post-CRT. Significant reductions were observed in QRS duration, PR interval, end-diastolic shape index, end-systolic shape index, stroke volume, and myocardial mass post-CRT. The CRT LV lead was positioned concordant, adjacent, and discordant in 11 (61.1%), 5 (27.8%), and 2 (11.1%) patients, respectively. End-systolic and end-diastolic eccentricity demonstrated reverse remodeling post-CRT.

CONCLUSIONS

LV lead implantation in CRT guided by gated SPECT scintigraphy is feasible. The placement of the electrode concordant or adjacent to the last segment to contract was a determinant of reverse remodeling.

Cardiac resynchronization therapy outcomes with left ventricular lead concordant with latest mechanical activation: A meta-analysis

BACKGROUND

For cardiac resynchronization therapy (CRT), image-guided approaches targeting left ventricular (LV) lead placement at the site of latest mechanical activation had inconsistent outcomes. We examined evidence for improved CRT outcomes when LV lead placement concordant with latest mechanical activation occurred.

METHODS

A review of EMBASE and PubMed was performed for randomized controlled trials or prospective observational studies from October 2008 through October 2020 comparing outcomes with concordant versus discordant LV lead placement. Meta-analyses were performed to assess the association between concordance and death, death or heart failure (HF) hospitalization, ≥ 15% reduction in LV end systolic volume (LVESV), and changes in LVESV or ejection fraction (LVEF).

RESULTS

From 5897 citations, nine publications (eight studies) with 1355 patients were selected; 975 with a concordant LV lead and 380 with a discordant lead. Mean age was 66-68 years, 82% were male, and 64% had ischemic cardiomyopathy. Meta-analyses demonstrated a statistically significant reduction in death/HF hospitalization at 2 years (OR 0.38; 95% CI 0.16, 0.92) and LVESV at 6 months (mean difference [MD] -13.4%; 95% CI -6.7%, -20.0%), and an increase in LVEF (MD 4.03; 95% CI 0.77, 7.30) with the concordant LV lead. There were trends toward decreased death at 2 years (OR 0.49; 95% CI 0.19, 1.23) and ≥ 15% reduction in LVESV at 6 months (OR 3.81; 95% CI 0.24, 61.24) with concordant LV lead placement.

CONCLUSION

A concordant LV lead was associated with better CRT outcomes. Further study of feasible methods to achieve LV lead concordance is needed.

Atrial and ventricular signal averaging electrocardiography in pacemaker and cardiac resynchronization therapy

Cardiac resynchronization therapy with atrioventricular and interventricular delay optimized biventricular pacing is an established therapy for symptomatic heart failure patients with prolongation of QRS duration, left bundle branch block and reduced left ventricular ejection fraction. The aim of the investigation was to evaluate right atrial, right ventricular and left ventricular electrical signals of implantable electronic cardiac devices with and without signal averaging technique with novel LabVIEW software. Electrical interatrial conduction delay and inter-ventricular conduction delay may be useful parameters to evaluate electrical atrial and ventricular desynchronization in heart failure patients.