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Benefits of Cardiac Resynchronization Therapy in an Asynchronous Heart Failure Model Induced by Left Bundle Branch Ablation and Rapid Pacing
Published on: December 11, 2017
Left ventricular lead proximity to an akinetic segment and impact on outcome of cardiac resynchronization therapy
Daniel Arzola-Castaner1, Cynthia Taub, E Kevin Heist
1Cardiac Arrhythmia Service, Cardiac Ultrasound Laboratory, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA.
Insights
Cardiac resynchronization therapy (CRT) lead placement near akinetic segments does not affect patient outcomes. Pacing site proximity to akinetic areas did not influence acute hemodynamic or long-term clinical response in CRT patients.
Area of Science:
- Cardiology
- Electrophysiology
- Heart Failure Management
Background:
- Optimal cardiac resynchronization therapy (CRT) pacing is typically along the left ventricular (LV) lateral and postero-lateral (PL) walls.
- The impact of pacing over an akinetic (non-contractile) cardiac segment on CRT response is not well understood.
Purpose of the Study:
- To investigate whether LV lead placement adjacent to an akinetic myocardial segment affects acute hemodynamic and long-term clinical outcomes in patients undergoing CRT.
- To compare CRT response based on LV lead position relative to akinetic segments.
Main Methods:
- 38 patients with ischemic cardiomyopathy received CRT.
- Acute hemodynamic response was assessed by the percentage change in dP/dt (%DeltadP/dt) using mitral regurgitation Doppler.
- LV lead position was determined and categorized as 'on' or 'off' an akinetic site identified via echocardiography.
Main Results:
- No significant difference in acute hemodynamic response (%DeltadP/dt) or 12-month clinical outcomes (heart failure hospitalization/mortality) was observed between patients paced on or off an akinetic site.
- Lead placement in postero-lateral (PL) or mid-lateral (ML) positions showed a trend towards better acute hemodynamic response compared to antero-lateral (AL) positions (P=0.014).
Conclusions:
- Left ventricular lead proximity to akinetic myocardial segments does not appear to influence the acute hemodynamic or 12-month clinical effectiveness of cardiac resynchronization therapy.
- Specific lead positions (PL, ML) may be associated with improved acute hemodynamic response, independent of akinetic segment proximity.
Background:
Previous studies report that the optimal pacing site for cardiac resynchronization therapy (CRT) is along the left ventricular (LV) lateral and postero-lateral (PL) wall. However, little is known regarding whether pacing over an akinetic site impacts the contractile response and long-term outcome from CRT.
Methods And Results:
A total of 38 patients with ischemic cardiomyopathy were studied for their acute hemodynamic and 12-month clinical response to CRT. The intraindividual percentage change in dP/dt (%DeltadP/dt), over baseline, was derived from the mitral regurgitation (MR) Doppler profile with CRT on versus off. Two-dimensional echocardiography was used for myocardial segmentation and determinination of akinetic sites. LV lead implant site was determined using angiographic and radiographic data and categorized as being "on" (group 1) or "off" (group 2) an akinetic site. Long-term response was measured as a combined endpoint of hospitalization for heart failure and/or all cause mortality at 12 months. Time to primary endpoint was estimated by the Kaplan-Meier method. Clinical characteristics and acute hemodynamic response was similar in both (group 1 [n = 14]; %DeltadP/dt 48.8 +/- 67.4% vs group 2 [n = 24]; %DeltadP/dt 32.2 +/- 40.1%, P = 0.92). No difference in long-term outcome was observed (P = 0.59). In contrast, lead placement in PL or mid-lateral (ML) positions was associated with a better acute hemodynamic response when compared to antero-lateral (AL) positions (PL, %DeltadP/dt 45.7 +/- 50.7% and ML, %DeltadP/dt 45.1 +/- 58.8% vs AL, %DeltadP/dt 2.9 +/- 30.9%, respectively, P = 0.014).
Conclusion:
LV lead proximity to an akinetic segment does not impact acute hemodynamic or 12-month clinical response to CRT.
