Cardiac resynchronization therapy

Cardiac resynchronization therapy

1. Welcome to 5 minutes presentation Dr. Sayeedur Rahman Khan Rumi [email protected] MD (Cardiology) Final Part Student National Heart Foundation Hospital and Research

2. Cardiac Resynchronization Therapy (CRT)

3. Typical LV myocardial activation occurs from the apex to base, simultaneously in the septum and in the LV free wall, and is described as synchronous . In the setting of conduction delay, the electromechanical coupling of the heart is disrupted, leading to dyssynchrony . Over time, electromechanical uncoupling leads to impaired stroke volume, worsened mitral insufficiency, prolonged LV isovolumetric events, and impaired diastolic filling. These effects contribute to adverse remodeling in the already impaired heart, creating a vicious cycle that perpetuates this process into more advanced HF.

4. TYPES OF DYSSYNCHRONY AV dyssynchrony Interventricular dyssynchrony Intraventricular dyssynchrony Others types: Mechanical dyssynchrony Electrical dyssynchrony

5. ASSESSMENT OF DYSSYNCHRONY Approximately 30% of patients meeting current implantation criteria fail to respond to CRT. Studies have revealed that up to 30% of patients with a prolonged QRS duration do not have mechanical dyssynchrony as assessed by MRI or echocardiography . W hereas up to 30% of patients with a normal QRS duration and symptomatic HF have evidence of mechanical dyssynchrony on echo or MRI and could potentially benefit from resynchronization therapy.

6. Echocardiographic assessment of dyssynchrony Pulsed-wave Doppler Septal to posterior wall motion delay Tissue Doppler imaging Three-dimensional imaging New echocardiographic indices of mechanical dyssynchrony : Strain imaging Speckle tracking

7. Commonly Used Echocardiographic Measurements of Dyssynchrony

8. ROLE OF CRT The primary role of CRT is to improve systolic and diastolic LV performance via an improvement in chamber efficiency, thereby leading to symptomatic improvements in patients with medication refractory HF. The systolic improvement is usually noticed within a week of device implantation . T he EF improved by an average of about 5% with a significant improvement in MR and was accompanied by symptomatic improvement. The remodeling of the LV takes at least 3 or more months.

9. CURRENT GUIDELINES AND RECOMMENDATIONS The Task Force for Cardiac Pacing and Cardiac Resynchronization Therapy of the European Society of Cardiology, in collaboration with the European Heart Rhythm Association, provides the following recommendations for CRT . The use of CRT or CRT-D is recommended in patients with HF who remain symptomatic in NYHA classes III–IV despite optimal medical therapy and with an LVEF ≤ 35%, LV dilation with LV end-diastolic diameter > 55 mm, NSR, and wide QRS complex (≥120 milliseconds) ( class I, level of evidence A for CRT; class I, level of evidence B for CRTD ).

10. The use of CRT is also recommended in patients with HF with NYHA classes III–IV despite optimal medical therapy and with an LVEF ≤ 35%, LV dilation, and a concomitant indication for permanent pacing (first implant or upgrade of conventional pacemaker) ( class IIa , level of evidence C ). The use of CRT is also recommended in patients with HF who remain symptomatic in classes III–IV despite optimal medical therapy and with an LVEF ≤ 35%, LV dilation, permanent atrial fibrillation, and indication for AV junction ablation ( class IIa , level of evidence C ). The use of CRT is also recommended in patients with HF who remain symptomatic in classes III–IV despite optimal medical therapy and with an LVEF ≤ 35%, QRS ≥ 130 milliseconds, permanent atrial fibrillation, and indication for AV junction ablation ( class IIa , level of evidence C ).

11. IMPLANTATION PROCEDURE Unlike conventional transvenous pacemaker or ICD implantation that requires lead placement in the right atrium and/or the right ventricle only, Bi-V pacing requires LV lead implantation. Initially , this was achieved via a thoracotomy; however, currently up to 98% of Bi-V devices are placed via a transvenous approach.

12. Typically, a cephalic or axillary vein approach to venous access is used . The right atrial and RV leads are implanted in a fashion similar to a pacemaker or ICD implantation. The LV lead is placed through the CS into a CS branch on the lateral free wall of the left ventricle. Performing an occlusive CS venogram may help identify the appropriate vein .

13. Thank You