XXXX after pacemaker implantation.

@entity1 @entity1479 @entity4264 @entity455 @entity955 @entity432 @entity850 @entity1211
BACKGROUND: Central vein leads are known to predispose to @entity432 . Although usually asymptomatic, obstruction may render electrode removal difficult. This study aimed at quantifying changes in venous calibers in a prospective fashion by intravenous contrast venography (ICV) before and after pacemaker (PM) or cardioverter-defibrillator implantation. METHODS: One hundred and fifty (mean age 67; 61% male) consecutive @entity1 were enrolled, and followed for 6 months. A successful ICV was done at baseline prior to implantation and at 6-month follow-up in 136 (91%) @entity1 . Minimum (D(min)) and maximum (D(max)) vessel diameters were obtained from both ICVs. A new @entity850 was defined as a 50% diameter reduction in a venous segment when compared to baseline. We implanted a total of 230 electrodes: 47 (34.6%) single lead, 84 (61.8%) 2-lead, and 5 (3.7%) 3-lead systems. RESULTS: At baseline ICV, 10 @entity1 (7%) were found to have @entity1211 , including 8 @entity1 with obstructive lesions, 1 @entity1 with a persistent @entity4264 , and 1 @entity1 with double axillary vein. At 6 months, a new obstructive @entity455 had developed in a total of 19 (14%) @entity1 , none of whom exhibited any local symptoms. Of these @entity1 14 (10%) had a @entity850 (mean D(min) 4.6 mm and diameter 38% of baseline), and 5 (3.6%) had a complete @entity432 . In most cases the new @entity850 developed in a location where the vessel was narrowest at baseline. Clinical predictors for the development of @entity850 were @entity955 at baseline and biventricular PM implantation. CONCLUSIONS: This is the first systematic study to quantify venous changes after PM or @entity1479 implantation. Our study shows that @entity1211 rendering PM implantation difficult are not infrequent. The incidence of new @entity432 was 14%. @entity955 and biventricular PM implantation were independent predictors of @entity432 .
