Cardiac Resynchronization Therapy Optimization

| May 08, 2009 | International | Electrophysiology | CRT Systems : CRTs

One-third of patients with low ejection fraction (EF) and class III to IV heart failure exhibit wide QRS duration.  Wide QRS duration is associated with ventricular dyssynchrony which, in turn, can manifest in:

  • Suboptimal ventricular filling
  • Reduction in left ventricular dP/dt (rate of rise of ventricular contractile force or pressure)
  • Prolonged duration and severity of mitral regurgitation
  • Paradoxical septal wall motion.1

The Challenge

Cardiac resynchronization therapy (CRT) is designed to improve myocardial performance by electrically activating the right and left sides of the heart to optimize atrioventricular, intraventricular and interventricular synchronization.  To optimize CRT and enhance clinical outcomes, studies recommend:

  • Selecting the shortest possible A-V delay which allows complete ventricular filling, thereby optimizing stroke volume and minimizing pre-systolic mitral regurgitation.2
  • Optimizing VV timing. 3,4,5

However, CRT programming can be challenging:

  • Optimal AV delays vary between patients6 and optimal AV and VV delays for individual patients change over time necessitating individualized and ongoing optimization7.

 

 Graph of optimal AV delay

  • Traditional echo-based methods of optimization require a skilled echo sonographer and coordination of clinical services which creates time, cost and other resource constraints 

The Solution

In one simple step, QuickOptTM Timing Cycle Optimization helps clinicians quickly achieve optimal hemodynamic performance for their patients through individually tailored AV delays. Using IEGM-based optimization, QuickOpt Optimization characterizes interatrial conduction patterns in order to maximize preload and allow proper timing of mitral valve closure. QuickOpt Timing Cycle Optimization provides a clinically proven 97% correlation to echocardiography, providing the opportunity for optimization of AV delay in about a minute at every visit.8

Clinical Evidence

Porciani, et al., used real-time 3D echocardiography to assess the clinical effects of QuickOpt Timing Cycle Optimization on LV asynchrony and performance. During patient follow-up (9 +/- 8 months post-implant) echocardiography was performed before and after QuickOpt optimization of AV and VV delays. The study found significant improvements in cardiac function.9


Baker, et al, compared IEGM methods and echocardiogram for optimization of AV and VV delay in heart failure patients.  IEGM was found to provide a reliable, clinically correlated alternative to echo-based optimization techniques.10

 

 

1 A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, J Am Coll Cardiol 2009; 53:1-90.

2 Schoenfeld MH. Contemporary Pacemaker and Defibrillator Device Therapy: Challenges Confronting the General Cardiologist. Circulation 2007; 115:638-653.

3 Sogaard, et al. Sequential Versus Simultaneous Biventricular Resynchronization for Severe Heart Failure: Evaluation by Tissue Doppler Imaging. Circulation 2002; 106:2078-2084.

4 Bordachar, et al. Echocardiographic Parameters of Ventricular Dyssynchrony Validation in Patients with Heart Failure Using Sequential Biventricular Pacing. JACC 2004; 44(11):2157-2165.

5 van Gelder BM, et al.  Effect of optimizing the VV interval on left ventricular contractility in cardiac resynchronization therapy.  Am J Cardiol 2004; 93(12):1500-1503.

6 O'Donnell, et al. Long-term variations in optimal programming of cardiac resynchronization therapy devices.  PACE 2005; 28 Supp S24-S26.

7 Delugio, et al. Chronic study of biventricular pacing.  Optimal AV delay determined via trans-mitral flow [abstract].  PACE 2001: Vol 24:651.

8 Porterfield JG, Porterfield LM, Baker JH, et al. Device based intracardiac delay optimization vs. echo in ICD patients [abstract]. Europace 2006, 8(suppl 1):176. 

9 Porciani MC.  A real-time three-dimensional echocardiographic validation of intracardiac electrogram based method for optimizing cardiac resynchronization.  PACE 2008; 31:56-63.

10 Baker et al. Acute evaluation of programmer-guided AV/PV and VV delay optimiztion comparing an IEGM method and electrocardiogram for cardiac resynchronization therapy in heart failure patients and dual-chamber implants. J Cardiovasc Electrophysiol 2007; 18;1-7.

 

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