What is the recommended approach for managing a patient with heart failure who is being considered for a Cardiac Contractility Modulation (CCM) implant?

Cardiac Contractility Modulation (CCM) Implant for Heart Failure

Primary Indication and Patient Selection

CCM is approved for patients with NYHA class III heart failure, LVEF between 25-45%, and QRS duration <130 ms who remain symptomatic despite optimal medical therapy and are not candidates for cardiac resynchronization therapy. 1

Specific Eligibility Criteria

• NYHA functional class: Class III symptoms despite guideline-directed medical therapy (GDMT) 1, 2
• Left ventricular ejection fraction: 25% to 45% 1, 2, 3
• QRS duration: <130 ms (narrow QRS complex, making them ineligible for CRT) 2, 3
• Sinus rhythm: Required for optimal CCM function 2
• Optimal medical therapy: Must be on maximally tolerated doses of ACE inhibitors/ARBs, beta-blockers, and mineralocorticoid receptor antagonists for ≥3 months 4

Pre-Implantation Assessment Algorithm

Step 1: Confirm Heart Failure Optimization

• Verify patient has been on GDMT for ≥3 months with ACE inhibitor (or ARB), beta-blocker, and MRA at target or maximally tolerated doses 4
• Consider sacubitril/valsartan as replacement for ACE inhibitor if patient remains symptomatic 4
• Ensure diuretics are optimized if signs of congestion present 4

Step 2: Exclude CRT Candidacy

• Measure QRS duration: if ≥130 ms with LBBB morphology, patient should receive CRT instead of CCM 4
• CRT is Class I recommendation for LVEF ≤35%, QRS ≥150 ms with LBBB, and NYHA class II-IV 4
• CCM fills the gap for patients with narrow QRS who cannot benefit from CRT 2

Step 3: Assess ICD Need

• If LVEF ≤35% and patient meets criteria, ICD is Class I recommendation for primary prevention 4
• CCM can be implanted alongside an existing ICD or as standalone device 5, 3
• Many CCM patients have concurrent ICDs given their LVEF range 5

Step 4: Evaluate Contraindications

• Active infection or recent cardiac surgery within 40 days 4
• Mechanical tricuspid valve (interferes with lead placement) 6
• Severe right ventricular dysfunction 6
• Life expectancy <1 year due to non-cardiac comorbidities 4

Expected Clinical Outcomes

Benefits Demonstrated in Clinical Trials

• Quality of life improvement: Significant improvements in Minnesota Living with Heart Failure Questionnaire scores 1, 3
• Exercise capacity: Enhanced 6-minute walk distance and functional capacity 1, 2
• Symptom improvement: NYHA class reduction maintained over 2 years 3
• Hospitalization reduction: 75% decrease in heart failure hospitalizations (from 1.2 to 0.35 per patient-year) 3

Mortality Data

• Three-year survival of 82.8% in patients with LVEF 25-45%, comparable to Seattle Heart Failure Model predictions 3
• Patients with LVEF 35-45% showed better survival than predicted (88.0% vs. 74.7%) 3
• Important caveat: Current evidence does not yet demonstrate mortality benefit, unlike CRT and ICD therapies 1

Comparison with Alternative Device Therapies

CCM vs. CRT-D

• CCM patients typically present with more advanced disease (lower baseline LVEF, worse NYHA class) but achieve comparable 12-month improvements in functional status and ventricular reverse remodeling 5
• CRT-D reduces paced QRS width, while CCM maintains intrinsic QRS width 5
• Heart failure hospitalizations occur more frequently with CCM (45.7% vs. 16.8% per patient-year), likely reflecting more advanced baseline disease 5

Mechanism Distinction

• CCM: Delivers high-voltage, long-duration electrical signals to right ventricular septum during absolute refractory period to enhance contractility without causing additional depolarization 1
• CRT: Resynchronizes ventricular contraction in patients with conduction delay 4
• ICD: Prevents sudden cardiac death but does not improve contractility 4

Post-Implantation Management

Device Follow-Up

• Initial assessment within 1 month post-implant to verify appropriate CCM signal delivery 4, 7
• Regular follow-up every 3-6 months to optimize device programming and assess clinical response 4, 7
• Monitor for device-related complications including lead dislodgement, infection, and phrenic nerve stimulation 7, 6

Continued Medical Optimization

• Continue GDMT with regular titration to target doses 4, 2
• Monitor renal function and electrolytes, particularly potassium, given triple neurohormonal blockade 4
• Avoid medications that worsen heart failure: NSAIDs, COX-2 inhibitors, thiazolidinediones, diltiazem, verapamil 4

Critical Pitfalls to Avoid

• Premature implantation: Do not implant CCM before ensuring 3 months of optimal medical therapy, as many patients improve with medication optimization alone 4
• Ignoring CRT eligibility: Always measure QRS duration; patients with QRS ≥130 ms and LBBB should receive CRT, which has proven mortality benefit 4
• Overlooking ICD indications: If LVEF ≤35%, patient requires ICD for primary prevention regardless of CCM candidacy 4
• Unrealistic expectations: Counsel patients that CCM improves symptoms and quality of life but lacks proven mortality benefit, unlike CRT and ICD 1
• Inadequate follow-up: CCM requires specialized device programming and troubleshooting; ensure access to experienced providers 7, 6

Expanding Indications

Recent real-world data suggest CCM may benefit patients with LVEF 35-45% (upper range of approved indication) with particularly favorable survival outcomes 3. However, this remains an area requiring further study, and current approval remains for LVEF 25-45% 1.