Cardiac contractility modulation in non-responders to cardiac resynchronization therapy

Area of Science:

• Cardiology
• Biomedical Engineering
• Heart Failure Management

Background:

• Cardiac Resynchronization Therapy (CRT) is a standard treatment for heart failure with asynchrony.
• A significant portion of patients (20-30%) do not respond to CRT, necessitating alternative or adjunctive therapies.
• Cardiac Contractility Modulation (CCM) is explored as a novel approach to enhance cardiac function.

Purpose of the Study:

• To evaluate the feasibility and efficacy of CCM as an adjunctive therapy in patients non-responsive to CRT.
• To assess the impact of CCM on cardiac contractility and hemodynamic parameters in this patient cohort.
• To identify potential complications and outcomes associated with CCM implantation in CRT non-responders.

Main Methods:

• Sixteen patients with heart failure, non-responsive to CRT and optimized medical therapy, received CCM implantation.
• CCM involves delivering non-excitatory impulses during the absolute refractory period to improve left ventricular (LV) contractility (measured by LV dp/dt).
• Acute hemodynamic changes were assessed during implantation, followed by prospective patient monitoring.

Main Results:

• CCM significantly increased acute left ventricular dp/dt by 14% (P < 0.001).
• Over a mean follow-up of 147 days, New York Heart Association (NYHA) class improved (3.4 to 2.8, P < 0.01) and ejection fraction increased (27.3% to 31.1%, P < 0.01).
• Complications included lead dislocations, cardiac decompensations, arrhythmias, and renal failure; 19% of patients experienced sudden death.

Conclusions:

• CCM is a feasible adjunctive therapy for CRT non-responders, offering potential benefits when other options are exhausted.
• The procedure carries calculated risks, with high mortality and event rates observed in this critically ill population.
• No electrical interference was noted between CCM and CRT systems.