To the Editor:
We would like to share in this letter our initial experience in implanting epicardial leads for left and biventricular pacing as well as congratulate the authors1 for the excellent results obtained. In our experience with our last four patients, it is possible to obtain a better view of the working area by making a higher incision, in the second or third intercostal space (in the left subclavicular region), to insert the video-assisted thoracoscopy device. In this way, instead of having the camera almost perpendicular (as shown in the photos from the cited article) and requiring different angles to see the different sectors, we can position the camera parallel to the long axis of the thorax leaving it effectively fixed there (with the help of a second operator who kept it fixed by simply placing the head of the device on the left shoulder of the patient) thereby considerably expanding the field of vision. Furthermore, as the incision is performed approximately in the same area where the generator will be implanted, the remaining scar is smaller, since once the endoscope is removed we only have to expand the incision and to make the pocket for the generator in the same place. The rest of our technique was effectively the same.
Theoretically, the epicardial approach allows us to choose at will the best possible place to implant the leads, although up to the present there is no clear evidence regarding how to choose the best implantation site (the basal posterolateral region is large). Thanks to the input of Julio Spinelli (an engineer at Guidant, United States) we have also modified our technique (for both endocardial and epicardial implants) as follows: we connect the patient to the programmer (we use a Medtronic programmer) in order to have at least one surface lead in it. Once the best possible anatomical site is chosen, we connect the lead for setting thresholds and take note of whether the sensor of our left lead coincides with the end-half of the native QRS complex of the patient. In this way we at least confirm we are in an area of electrical delay. Otherwise, we will not be "resynchronizing" but possibly creating further asynchronism. Although the ultrasound scan tries to find out how to optimally guide the bi-ventricular pacing,2 the problem is that the settings are adjusted once the leads have been implanted in a given place. If the principle is to resynchronize areas with electromechanical delay by electric stimulation, it seems logical not to stimulate an area where there is no electric delay, even if this is a good anatomical site.
Once again, we would like to congratulate you for your excellent work.