For the pocket a cm incision was made along
For the pocket, a 6cm incision was made along the predefined Langer’s lines. Subcutaneous dissection was carried out using an electrosurgical cutting and coagulation device, parallel to the incision, down to the fascia overlying the latissimus dorsi muscle (shining transparent membrane).
Intermuscular sars-cov places the S-ICD in the virtual space between the latissimus dorsi and serratus anterior muscles (Fig. 1). This area may be accessed with scissors by a blunt dissection, parallel to the vertical latissimus dorsi muscle fibers. When the serratus anterior is reached, it is important to recognize the change in the fiber pathway, horizontal versus vertical, so that the muscular fascia may be preserved in order to minimize bleeding. The pocket was formed over the serratus anterior muscular fascia and beneath the latissimus dorsi muscle by detaching the fibrous tissue between the muscles.
Electrode positioning was performed following the two-incision technique described by Knops and co-workers . Once the electrode was connected to the generator and the latter was seated in the pocket, two separate non-absorbable sutures were inserted through the connector block suture portal and a suture knot was tied to anchor the S-ICD to the latissimus dorsi muscle, preventing both device migration and rotation.
Results An S-ICD was implanted in 14 consecutive patients using the intermuscular pocket approach for device positioning. The characteristics of the patient population are displayed in Table 1. All patients underwent pre-implant screening using the only commercially available S-ICD pre-implant screening tool; all patients had at least two vectors suitable for S-ICD sensing (three vectors in 6 patients). The implantations, including the defibrillation test (DFT), were each performed within 60 minutes (55±12min). The DFT was performed after the generator had been positioned in the pocket and the pocket closed completely. The most time-consuming step was the closing of the wound to ensure optimal cosmetic results. No specific bleeding issues were encountered during the procedures. In all patients, the DFT was performed at 65J after induction of ventricular fibrillation (VF) by 50-Hz burst stimulation. The DFT was deemed successful if the device detected and converted the ventricular tachycardia (VT) or VF into sinus rhythm using 65-J standard polarity. During VF conversion testing, all 14 episodes of induced VT or VF resulted in accurate arrhythmia detection and termination with a shock energy ≤65J and with mean time to therapy of 15.1±2.2s (range 12–19s). After implantation, all patients had at least two vectors suitable for S-ICD sensing based on the S-ICD software algorithm. No significant differences were found in terms of vector suitability determined by the pre-implant screening tool (ECG screening) and the S-ICD software algorithm. During a mean follow up of 9 months (range 3–12 months), no dislocations of either the S-ICD pulse generator or the electrode were observed on routine chest X-rays obtained 1day and 2 months after implantation. One patient reported mild discomfort from the S-ICD pocket during the first week after implantation. This discomfort resolved spontaneously and did not necessitate pocket revision. No infections, hematoma formations, or skin erosions occurred during the follow up. All device parameters were in range; in particular, no difference was found in terms of vector suitability for S-ICD sensing. All patients were comfortable with the position and appearance of the device (Figs. 2 and 3).
Discussion Because of the absence of appropriate or inappropriate shocks in our series of patients, we have no data about the arrhythmia termination efficacy during spontaneous VT/VF. Based on the high rate of DFT efficacy (100% at implantation), we may expect shock conversion efficacy during spontaneous arrhythmia events to be at least comparable with the efficacy rates reported in previous published studies [5–7]. Moreover, the nearer to the heart the pulse generator is placed, the more the shock vector efficacy might be improved. With the intermuscular pocket approach, the S-ICD is nearer to the heart than it is in the conventional subcutaneous approach.