Late complications following permanent pacemaker implantation or elective unit replacement.

OBJECTIVE: To determine the rate of late complications following first implantation or elective unit replacement of a permanent pacemaker system. DESIGN: Analysis of pacemaker data and complications prospectively acquired on a computerised database. Complications were studied over an 11 year period from January 1984 to December 1994. SETTING: Tertiary referral cardiothoracic centre. PATIENTS: Records of 2621 patients were analysed retrospectively. MAIN OUTCOME MEASURES: Complications requiring repeat procedures occurring more than six weeks after pacemaker implantation or elective unit replacement. RESULTS: The overall rate of late complications was significantly lower after first implantation of a permanent pacemaker (34 cases, complication rate 1.4%, 95% confidence interval 0.9% to 1.9%) than after elective unit replacement (16 cases, complication rate 6.5% (3.3% to 9.7%). There were 20 cases of erosion, 18 infections, five electrode problems, and seven miscellaneous problems. Complications were more common with inexperienced operators (18.9% (6.0% to 31.8%)) than with experienced operators (0.9% (0.3% to 1.5%). CONCLUSIONS: The incidence of late complications following pacemaker implantation is low and compares favourably with early complication rates. The majority are caused by erosion and infection. Patients who have undergone elective unit replacement are at particular risk.

Measurement of myocardial blood flow with positron emission tomography before and after transmyocardial laser revascularization.

BACKGROUND: Transmyocardial laser revascularization (TMLR) has been proposed for treatment of refractory angina. It has been hypothesized that transmural left ventricular channels created by laser improve myocardial blood flow (MBF) in the treated zones. We aimed to assess the effect of TMLR on MBF and coronary vasodilator reserve (CVR). METHODS AND RESULTS: We measured MBF by means of PET with (15)O-labeled water in 7 patients with refractory angina, Canadian Cardiovascular Society (CCS) class 3.6+/-0.5, on 3 occasions: before and at 7.5+/-2.8 weeks (FU-1) and 34.6+/-4.7 weeks (FU-2) after TMLR performed with a synchronized, high-powered CO(2) laser. In each study, MBF was measured at rest and during maximal intravenous dobutamine. CVR was computed as dobutamine divided by resting MBF. After TMLR, CCS class was 2.2+/-1.7 at FU-1 and 2.4+/-1 at FU-2 (P=0.04 versus pre-TMLR). Resting MBF in both lasered and nonlasered regions was unchanged after TMLR. Dobutamine MBF at baseline was 1.45+/-0.52 and 1.55+/-0.52 mL. min(-1). g(-1) in lasered and nonlasered regions, respectively (P=NS). At FU-1, dobutamine MBF in nonlasered regions had increased significantly to 1.89+/-0.82 mL x min(-1) x g(-1) (P<0.05) and was higher than in lasered regions (1.51+/-0.61 mL x min(-1) x g(-1); P<0.05 versus nonlasered). At FU-2, dobutamine MBF in nonlasered regions was still higher than in lasered regions (1.56+/-0.54 versus 1.21+/-0.44 mL x min(-1) x g(-1); P<0.01). CVR was comparable in nonlasered and lasered regions at baseline and FU-1, whereas it was higher in nonlasered regions at FU-2 (1.86+/-0.67 versus 1.53+/-0.72 mL x min(-1) x g(-1); P<0.05). CONCLUSIONS: TMLR has been shown to reduce angina in severely diseased patients. The results of our study do not support the hypothesis that the symptomatic benefit of TMLR can be ascribed to improved myocardial perfusion or CVR in lasered areas.