Coronary sinus electrodes

Benedict et al. (1986) modified the electrical induction of thrombosis by use of two Doppler flow probes proximal and distal to the needle electrode in order to measure changes in blood flow velocity. The electrical current was stopped at 50 % increase in flow velocity and thrombosis then occurred spontaneously. The important role of serotonin was demonstrated by increases in coronary sinus serotonin levels just prior to occlusion. 

Fig. 8. Anteroposterior chest radiograph. Pacemaker electrodes passing through left-sided SVC, entering distal coronary sinus.

Fig. 9. Curved multiplanar reformation, CT. Pacemaker electrodes passing through single PLSVC into coronary sinus.

LV pacing has undergone considerable evolution in its short history. Initially, pacemaker electrodes were placed in the coronary sinus using a stylet-driven technique. This has evolved to the currently acceptable use of a guiding catheter contrast venography for either a stylet-driven or some form of guidewire-assisted placement. 

After venous access, some consideration should be given to the sequence of lead placement. Some operators prefer to place the RV electrode first for emergency RV pacing, should heart block ensue because the heart failure patients commonly have a left bundle branch block and any trauma to the conduction system or right bundle may result in complete heart block. Other operators choose to place the coronary sinus lead first and, if necessary, depend on heart rate support via a temporary transvenous pacemaker placed via the femoral vein. The issue of failure speaks for placing the coronary sinus lead first. Should the procedure fail with unsuccessful left-sided left ventricular lead placement and the patient has already received right-sided electrodes, a pacing system may be left without an indication unless a future second attempt is considered. As more and more systems are placed for a primary prevention indication like MADIT II, this has become less problematic (153). 

Although extremely safe, epicardial left ventricular electrode placement via the coronary sinus is associated with some potential life-threatening complications. The major ones are listed in Table 4.18. 

IV. Add coronary sinus lead ipsilaterally plus contralateral endocardial pacing and shocking electrode placement... 

Hunt D, Sloman G. Long-term electrode catheter placement from coronary sinus. Br Med J 1968 4 495 96. 

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