Reduction in pacing rate and pain during cardiac contractility modulation: an overview of the problem and its solution using device programming

Aim. Evaluation of a patient group with a reduced percentage of stimulation, pain sensation, and the impact of adjusting stimulation programming parameters on achieving a positive effect from cardiac contractility modulation (CCM) therapy.

Methods. The study included 117 patients implanted with a CCM device. Personalized parameter settings were programmed intraoperatively and postoperatively. Transthoracic echocardiography (TTE) was performed before implantation and 6 months after surgery.

Results. The median age was 59.5 years, with 93.7% being male patients. The primary etiology of heart failure was ischemic heart disease (53.8%). A part of patients required a reduction in stimulation amplitude from 7.5 V (79%) to a maximum of 5 V (9%). After 6 months, the group with 7.5 V stimulation amplitude showed a significant increase in LVEF to 37 [32; 43] % (p=0.0001). However, in the group with 5 V stimulation amplitude, the increase in LVEF did not reach statistical significance during follow-up: 35 [34; 40] (p=0.211). Patients without discomfort during CCM therapy had lower LVEF (p=0.048), increased LV volumes (p=0.024; p=0.034), and a thinner LV posterior wall (p=0.028). However, the relationship between cardiac wall thickness and pain during ССМ therapy requires further research. Also, in patients without stimulation discomfort, the electrodes were more frequently implanted in the middle third of the interventricular septum (p=0.025). 83.7% of patients were programmed with standard stimulation duration - 7 hours per day (hrs/day). For 5.9%, the stimulation duration was 10 to 14 hours due to failure to achieve the required stimulation percentage. In this patient group, increasing the stimulation duration achieved a stimulation percentage exceeding 70%. In 15.3% of cases, patients with a CCM device had a therapy percentage above 90%. In 68.3% of cases, the daily therapy percentage was 80- 90%, and in 12% - 70 to 80%. A positive, moderate, significant correlation was noted between the stimulation percentage and the increase in LVEF (r=0.3; p=0.05).

Conclusion. CCM is an effective method of interventional treatment for patients with CHF. When programming CCM devices, it is necessary to achieve a stimulation percentage exceeding 70% per day, as the stimulation percentage directly correlates with an increase in myocardial contractility. Additionally, the stimulation amplitude should reach the target level of 7.5 V. If pain occurs, a reduction in stimulation amplitude to the minimum tolerable level is permissible. Further study of the nuances of device operation and training of specialists in programming intracardiac devices are necessary.

1. Galyavich AS, Tereshchenko SN, Uskach TM, et al. 2024 Clinical practice guidelines for Chronic heart failure. Russian Journal of Cardiology. 2024;29(11): 6162. (In Russ.) https://doi.org/10.15829/1560-4071-2024-6162.

2. Lund LH, Jurga J, Edner M, et al. Prevalence, correlates, and prognostic significance of QRS prolongation in heart failure with reduced and preserved ejection fraction. European Heart Journal 2013; 34(7): 529-39 https://doi.org/10.1093/eurheartj/ehs305.

3. Winter J, Brack KE, Ng GA. Cardiac contractility modulation in the treatment of heart failure: initial results and unanswered questions. European Journal Heart Failure. 2011 Jul;13(7): 700-10. https://doi: 10.1093/eurjhf/hfr042.

4. Safiullina AA, Uskach TM, Sapelnikov OV, et al. Improvement of the technique of positioning the endocardial electrodes of the cardiac contractility modulation device in patients with CHF with reduced ejection fraction and atrial fibrillation. Terapevticheskii arkhiv. 2024;96(7): 675-682 (In Russ) https://doi.org/10.26442/00403660.2 024.07.202782.

5. Lyon AR, Samara MA. Feldman DS. Cardiac contractility modulation therapy in advanced systolic heart failure. Nature Reviews Cardiology. 2013;10: 584-598. https://doi.org/10.1038/nrcardio.2013.114.

6. Mohri S, Shimizu J, Mika Y, et al. Electric currents applied during refractory period enhance contractility and systolic calcium in the ferret heart. American Journal of Physiology-Heart and Circulatory Physiology. 2003;284(4): H1119-23. https://doi: 10.1152/ajpheart.00378.2002.

7. Imai M, Rastogi S, Gupta RC, et al. Therapy with cardiac contractility modulation electrical signals improves left ventricular function and remodeling in dogs with chronic heart failure. Journal of the American College of Cardio­ logy. 2007; 29;49(21): 2120-8. https://doi: 10.1016/j.jacc.2006.10.082.

8. Pappone, C. et al. First human chronic Experience with cardiac contractility modulation by nonexcitatory electrical currents for treating systolic heart failure. Journal Cardiovascular. Electrophysiology. 2004;15: 418-427. https://doi.org/10.1046/j.1540-8167.2004.03580.x.

9. Morita H, Suzuki G, Haddad W, et al. Long-term effects of non-excitatory cardiac contractility modulation electric signals on the progression of heart failure in dogs. European Journal Heart Failure. 2004;6(2): 145-150. https://doi.org/10.1016/j.ejheart.2003.11.001. PMID: 14984721.

10. Kadish A, Nademanee K, Volosin K, et al. A randomized controlled trial evaluating the safety and efficacy of cardiac contractility modulation in advanced heart failure. American Heart Journal. 2011;161(2): 329-337.e1-2. https://doi.org/10.1016/j.ahj.2010.10.025.

11. Amanatova VA, Uskach TM, Vashtanian AK, Drozdov DV. Interpretation of electrocardiograms and results of daily ECG Holter monitoring in patients with an implanted cardiac contractility modulator. Medical alphabet. 2024;1(6): 21-26. (In Russ.) https://doi.org/10.33667/2078-5631-2024-6-21-26.

12. Имплантируемый генератор импульсов OPTIMIZER® Smart. Инструкция по применению. № части: 13-290-008‑ru -2016. [Электронный ресурс]. URL: https://impulse-dynamics.com/global/wp-content/uploads/sites/2/2020/10/13-290-008-ru-OPTIMIZER-Smart-IPGIFU-Russian-Rev‑10.pdf. Implantable pulse generator OPTIMIZER® Smart. Instructions for use. Part number: 13-290-008‑ru-2016. [Electronic resource].