Cardiac Resynchronization Therapy in Difficult Coronary Sinus Anatomy

Figure 1. Diagnostic Evaluation Before CRT Implantation (A) 12-lead electrocardiogram showing sinus rhythm with complete left bundle branch block with QRS duration of145 ms. (B) Apical 4-chamber view on 2D echocardiography revealing volume overload of the left ventricle. (C) Apical 4-chamber view with color Doppler imaging of the mitral valve showing mild to moderate mitral regurgitation. 2D = two-dimensional; CRT = cardiac resynchronization therapy.

Figure 2. Levophase Imaging of Left Coronary Artery Showing Coronary Sinus Anatomy Coronary angiography shows a narrowed ostioproximal coronary sinus with its aberrant anatomical location (red arrow).

Figure 3. Procedural Key Steps for Trans-Septal LV Endocardial Lead Implantation (A) A 260-cm coated 0.035-inch wire was advanced into the LA after trans-septal puncture via femoral route. (B) The coated wire was further advanced into the descending thoracic aorta through the LV with the help of a 5-F internal mammary artery catheter. (C) The floppy end of the coated wire was successfully snared from the right common iliac artery using a 20-mm snare. (D) The stiff end of the same wire was snared from the left subclavian vein and externalized through the left subclavian vein for sheath delivery. (E) A C315 His catheter with dilator was advanced over the wire into the left ventricle lateral wall. (F) A thin (4.1-F), lumenless bipolar pacing lead (SelectSecure 3830, Medtronic) was delivered through the sheath and actively screwed to the LV lateral endocardium. LA = left atrium; LV = left ventricle.

Figure 4. Postprocedural Assessment and 6-Month Follow-Up (A) Fluoroscopic right anterior oblique 30° view showing the RA, RV, and LV endocardial leads in situ. (B) Twelve-lead electrocardiogram demonstrating biventricular pacing rhythm with narrow-paced QRS complex (100 ms), indicating electrical synchrony. (C) Two-dimensional echocardiography apical 4-chamber view showing improved volume overload status. (D) Parasternal short-axis view at the midventricular level demonstrating the LV endocardial lead implanted on the LV lateral wall (arrow). (E) Apical 4-chamber color Doppler echocardiography showing reduced mitral regurgitation grade. LV = left ventricular; RA = right atrial; RV = right ventricular.