Implantation
LPM implantation was performed a median of 8 days following admission in ICU (range 1-180, IQR 10 days) (Table 2 ). Indication was high degree atrioventricular block in 86 patients, and sick sinus syndrome in 13. Only 52% of patients had a concomitant atrial arrhythmia.
LPM implantation was successfully performed in all but 2 cases (98%): no adequate acute pacing threshold (≤2.0 volts) could be obtained after up to 15 different positionings in 1 patient; the tricuspid valve could not be crossed in 1 patient with a history of heart transplantation. Approach was through the right femoral vein in 95 patients, left femoral vein in 4. A total of 71% of patients underwent a single positioning before reaching a final position (91% interventricular septum, 9% right ventricular apex), the total of positionings being ≤2 in 88% of cases. Median pacing threshold at implantation was as low as 0.38 volt, with 0.24 millisecond of pacing spike duration (range 0.13-1.63, IQR 0.25 volt).
A total of 4 procedure-related cardiac injuries occurred: 3 patients with a tamponade requiring percutaneous pericardial drainage, and 1 with a well-tolerated pericardial effusion (Table 3 ). One patient died, an 82-year-old woman hospitalized following a prolonged cardiac arrest due to complete atrioventricular block: a cardiac tamponade after the procedure was successfully drained, however she developed rapid lethal multi-system organ failure. Patients with cardiac injury were significantly more likely to have diabetes (75% versus 26%, p=0.04), liver failure (75% versus 5%, p=0.001) and normal coronary arteries (100% versus 42%, p=0.0002).
No complication related to the vascular access (groin hematoma, fistula, etc) occurred.