This was a single-centre retrospective study of 204 consecutive patients (age 83 ± 6 years, 68% female, 72% HFrEF) with NYHA class II-IV HF and moderate and moderate-to-severe (grade 2 + or 3+) SMR planned for CMCS implantation between 2021 and 2024.

At 3 months:

• NYHA class improved by ≥1 category in 94% of patients and 98% achieved NYHA class I or II.
• MR decreased by ≥1 grade in 91% of patients, with all patients classified as grade 1+ or 2+ post-procedure.
• Vena contracta width decreased (6.43 ± 0.84 to 3.85 ± 1.19 mm; P < 0.001), and there was a reduction of LA area from 44.4 ± 6.0 to 35.4 ± 5.1 cm2 (P < 0.001).
• Diastolic filling was improved (change in E/E′ ratio from 20.1 ± 5.5 to 14.0 ± 3.8; P < 0.001), systolic pulmonary artery pressure was lower in follow-up (44 ± 11 to 35 ± 9 mm; P < 0.001), and there was also a clinically relevant reduction in median BNP levels from 2849 to 1390 pg/mL (P < 0.001).
• These changes were not different between HFrEF and HFpEF.