Cardiac Devices for Heart Failure Monitoring
For heart failure monitoring, cardiac resynchronization therapy devices (CRT-D or CRT-P) are the recommended cardiac devices, with CRT-D (combined resynchronization and defibrillator) preferred for most patients meeting criteria, as these devices not only monitor but actively treat heart failure through biventricular pacing while providing defibrillation capability. 1
Device Selection Based on Clinical Criteria
CRT-D (Cardiac Resynchronization Therapy with Defibrillator)
CRT-D is the primary recommendation for patients meeting all of the following criteria: 1
- LVEF ≤35% 1
- NYHA class II-IV symptoms on guideline-directed medical therapy 1
- QRS duration ≥120 ms (strongest evidence for ≥150 ms with LBBB pattern) 1
- Sinus rhythm 1
- Life expectancy >1 year with good functional status 1
The 2022 AHA/ACC/HFSA guidelines provide Class 1 (strongest) recommendation for CRT-D in patients with LVEF ≤35%, sinus rhythm, LBBB with QRS ≥150 ms, and NYHA class II-IV symptoms, as this combination reduces total mortality, hospitalizations, and improves symptoms and quality of life. 1
CRT-P (Cardiac Resynchronization Therapy with Pacemaker Only)
CRT-P should be considered instead of CRT-D when: 1
- Life expectancy <1 year due to non-cardiac comorbidities 2
- Patient preference after informed discussion 2
- High risk of non-sudden death (frequent hospitalizations, advanced frailty, severe renal dysfunction, systemic malignancy) 1
- NYHA class III-IV patients where ICD benefit is unlikely to provide meaningful survival benefit 1
The European Society of Cardiology gives this a Class IIa recommendation, recognizing that while CRT improves symptoms and quality of life, the defibrillator component may not benefit patients with limited life expectancy from non-cardiac causes. 1
Special Monitoring Indications
Atrial Fibrillation Patients
For patients with atrial fibrillation, CRT-D/CRT-P can be useful when: 1
- LVEF ≤35% 1
- Atrioventricular nodal ablation or rate control allows near 100% ventricular pacing 1
- QRS ≥130 ms 1
- NYHA class III-IV symptoms 1
This receives a Class IIa recommendation, as achieving consistent biventricular pacing is critical for CRT benefit. 1
Anticipated Frequent Ventricular Pacing
CRT should be considered for patients requiring >40% ventricular pacing: 1
This prevents the detrimental effects of chronic right ventricular pacing in patients with existing left ventricular dysfunction. 1
Critical Pitfalls to Avoid
Do not implant a standard ICD without CRT capability in patients meeting CRT criteria - this misses the opportunity for reverse remodeling and heart failure symptom improvement. 2 The American College of Cardiology gives this a Class I recommendation with Level B evidence. 2
Do not implant CRT devices in patients with QRS <120 ms - there is no evidence of benefit and may cause harm (Class III recommendation). 1, 2 The exception is patients requiring frequent ventricular pacing. 1
Do not use echocardiography alone to determine CRT candidacy - patients should not be denied CRT based solely on echocardiographic parameters, as echo is poor at determining "need" or "response" to CRT. 1
Evidence Quality Considerations
The RAFT trial (2010) demonstrated that CRT-D reduced the primary endpoint of death or heart failure hospitalization by 25% compared to ICD alone in patients with NYHA class II-III heart failure. 3 The MADIT-CRT trial extended these benefits to less symptomatic patients (NYHA class I-II) with LVEF ≤30% and QRS ≥130 ms. 1, 4
The COMPANION trial showed CRT-P/CRT-D reduced all-cause death or hospitalization, with CRT-D showing additional mortality benefit over CRT-P alone. 1 However, the choice between CRT-P and CRT-D should be individualized based on sudden death risk versus non-sudden death risk. 1
All CRT patients require regular device checks (at least annually) and optimization of device settings, as heart failure is a progressive disease requiring ongoing adjustment of both medical therapy and device programming. 1