Orthodromic and Antidromic Snare Techniques for Left Ventricular Lead Implantation in Cardiac Resynchronization Therapy

Figure 1. Study Flow. According to LV lead implantation method, patients were classified into the snare technique group and the conventional method group. CRT, cardiac resynchronization therapy; LV, left ventricle.

Figure 2. The Orthodromic Snare Technique. (A) Venography showed that the proximal portion of the target branch (anterolateral vein) was tortuous with a connecting vein present between anterolateral and posterolateral veins. (B) A 0.014″ guidewire was advanced into the anterolateral vein and back into the CS ostium via the connecting vein (white arrow). (C) LV lead insertion into the target branch was unsuccessful due to its tortuous course. (D) The distal end of the guidewire was snared at the right atrium. (E) The distal end of the guidewire was snared out of the sheath. The LV lead was inserted via the guidewire proximal end (yellow arrow), and they traveled in the same direction. (F) Successful LV lead implantation into the anterolateral vein. CS, coronary sinus; LV, left ventricle; RV, right ventricle.

Figure 3. The Antidromic Snare Technique. (A) Venography showed the target vein (lateral) and the connecting vein to the middle cardiac vein. (B) Failure to advance the LV lead into the target vein. (C) Re-wiring into the target branch was unsuccessful due to the dissected ostium of the target vein. (D) The 0.014″ guidewire was advanced into the middle cardiac vein and back into the CS ostium via the connecting vein (white arrow). (E) The guidewire distal end was snared at the right atrium. (F) The distal end of the guidewire was snared out of the sheath. The LV lead was advanced into the target vein via the guidewire distal end (yellow arrow). The LV lead and guidewire traveled in opposite directions. CS, coronary sinus; LV, left ventricle.

Figure 4. LV Lead Pacing Threshold and Impedance between the Snare and Conventional Groups. (A) LV lead pacing threshold and (B) LV lead impedance at baseline and 3, 6, 12, and 24 months after CRT implantation was compared between the snare and conventional groups. CRT, cardiac resynchronization therapy; LV, left ventricle.

Figure 5. Comparison of Electrocardiographic and Echocardiographic Responses between the Snare and Conventional Groups. (A) Absolute increase in LVEF, (B) relative reduction in LVESV, (C) follow-up QRS duration (msec), and (D) responder rates (%) are compared between the snare and conventional groups. Values are mean ± standard deviation or proportion (%). In box-and-whisker plots, horizontal line indicates median value, box indicates the interquartile range, and whiskers indicate the minimum and maximum values excluding outliers. LVEF, left ventricular ejection fraction; LVESV, left ventricular end-systolic volume.

Figure 6. Comparison of Clinical Outcomes between the Snare and Conventional Groups. (A) The primary outcome (a composite of all-cause death or heart failure readmission) and (B) cardiac death compared between the snare and conventional groups.