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Assessing Non-invasive Studies to Evaluate Resynchronization Pacing Effectiveness in the Young
Dipika Menon1, Sanjeev Aggarwal1, Gilda Kadiu1
1Section of Cardiology, Department of Pediatrics, The Children's Hospital of Michigan, Wayne State and Central Michigan University Schools of Medicine, Detroit, MI, USA.
Insights
Newer non-invasive strain measurements, including global longitudinal strain and left atrial strain, provide more accurate assessments of cardiac resynchronization therapy (CRT) response in young patients with heart failure. These advanced echocardiographic parameters correlate better with clinical and hemodynamic improvements than traditional methods.
Area of Science:
- Cardiology
- Biomedical Engineering
- Pediatric Heart Disease
Background:
- Established non-invasive assessments for cardiac resynchronization therapy (CRT) response in young patients, particularly those with congenital heart disease (CHD), are lacking.
- Traditional echocardiography (ECHO) parameters like ejection fraction (EF) and QRS duration can be unreliable in this population due to anatomical variations, prior surgeries, and pacemakers.
Purpose of the Study:
- To correlate updated non-invasive assessments, including novel strain parameters, with clinical and invasive hemodynamic evaluations of CRT response in young patients.
- To establish more reliable non-invasive methods for assessing CRT efficacy in pediatric and young adult populations.
Main Methods:
- Sixteen young patients (mean age 18.5 years) with heart failure (NYHA II-III) underwent CRT.
- Assessments included clinical status (NYHA), invasive hemodynamics (dP/dt-max), ECG, and ECHO (including global longitudinal strain [GLS] and left atrial strain [LAS]) pre-CRT and at 1-month and 1-year post-CRT.
Main Results:
- All patients showed clinical improvement (NYHA II-III to I-II) and increased contractility (dP/dt) after 1 year.
- Standard ECHO parameters (EF, dimensions) showed minimal change, while GLS and LAS significantly improved post-CRT.
- QRS duration shortened only in patients with pre-existing pacemakers.
Conclusions:
- Cardiac resynchronization therapy is effective in younger patients with heart failure, including those with CHD.
- Novel echocardiographic strain parameters (GLS, LAS) offer superior, more accurate non-invasive assessment of CRT response compared to traditional metrics in this population.
Abstract:
Appropriate non-invasive assessments (ECHO/ECG) of cardiac resynchronization pacing therapy (CRT) among younger patients (pts) with/without (w/wo) congenital heart disease (CHD) are not established. Ejection fraction (EF) and QRS can be unreliable due to anatomy, surgical repairs, and pre-existing pacemakers (PM). This study correlates updated non-invasive studies, including newer strain values, with clinical and invasive hemodynamic assessments of CRT response in the young. Sixteen pts (mean age 18.5 ± 6 years, 10/16 with pre-existing pacemakers) underwent CRT for heart failure (NYHA II-III). CHD included septal defects and Tetralogy of Fallot. Assessment of CRT efficacy was based on clinical findings, direct catheterization studies [pressures, contractility indices (dP/dt-max)], ECG changes, and ECHO studies [including updated global (GLS), left atrial strain (LAS), and sphericity indices] pre- and at 1-month and 1-year post-CRT. After 1 year following CRT, all pts improved (II-III to I-II) in clinical NYHA status. Contractility (dP/dt) increased (932 ± 351 vs 561 ± 178.7 mmHg-sec [p = 0.001]). QRS duration shortened only among pts with pre-existing PM (160 ± 25 vs 134 ± 25 ms [p = 0.02]). Standard ECHO parameters, including chamber dimensions and EF, showed no appreciable changes from pre-CRT values. However, endocardial GLS [(- 6.4 vs. - 9.6%) p = 0.0003] and LAS [(- 5.8 vs - 9.3%) p = 0.02] values significantly improved. Although CRT is applicable to younger pts, accurate non-invasive evaluations of response are lacking. This study establishes that newer strain values better correlate with clinical and hemodynamic changes over other parameters and offer more appropriate assessments of CRT response.
