CCM (cardiac contractility modulation) is a very promising therapy in heart failure patients as it allows, by increasing intracellular calcium handling, an improvement in cardiac contractility, ejection fraction, and patient quality of life.
It delivers high-energy (7.5 V) and long-duration (about 20 milliseconds) pulses in absolute refractory period through the use of two leads on the right ventricular septum.
It is indicated in patients with narrow QRS (< 130 msec) and ejection fraction between 25 and 45%.
Therefore, a large proportion of patients suitable for CCM therapy also have an indication for ICD implantation.
The coexistence of an ICD (single-chamber or dual-chamber) and CCM presupposes the presence of 3 leads in the right ventricle and possibly a catheter in the right atrium if a dual-chamber ICD is used. The presence of numerous leads increases the risk of infection, mechanical complications, and damage on the leads.
In view of the above, the strategy we propose in patients with concomitant indication for ICD and CCM is the use of the subcutaneous defibrillator (S-ICD) in patients with potential indication for CCM, narrow QRS, no pacing indication, and ejection fraction <35%, thus limiting the number of leads and the risk of complications.
In our center, we have started using this strategy with excellent clinical results and in the absence of complications.
One of the cases treated with this strategy is a 60-year-old patient with nonischemic dilated myocardiopathy, ejection fraction 34%, QRS < 130 msec, NYHA class III, despite therapy with beta blockers, ARNI, SGLT2-i, MRA at the maximum dose. The patient, also considering the potential future need for CCM implantation, underwent S-ICD implantation. After 3 months, NYHA class III with reduced quality of life persisted (MLHFQ 82). Therefore, the patient successfully underwent CCM implantation, with marked improvement in symptoms (MLHFQ 71) and ejection fraction (43%) 3 months later. This strategy avoided the placement of additional leads in the right ventricle while ensuring protection from potentially fatal arrhythmias and improvement in contractile function and symptoms.
We suggest the use of the subcutaneous defibrillator (S-ICD) in all patients in whom there might be an indication for the use of CCM and no need for pacing, ensuring maximum efficacy and reducing the risk of infection and leads related complications.