The myocardial phosphocreatine-to-ATP ratio, measured noninvasively with 31P-MR spectroscopy, is a predictor of both total and cardiovascular mortality in patients with dilated cardiomyopathy.

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A higher incidence of pacemaker related complications has been reported in DDD systems as compared to VVI devices. The implantation of single lead VDD pacemakers might reduce the complication rate of physiological pacing in patients with AV block. In a retrospective study, the data records of 1,214 consecutive patients with pacemaker implantation for AV block between 1990 and 2001 (VVI 36.5%, DDD 32.9%, VDD 30.6%) were analyzed. Complications requiring surgical interventions were compared during a follow-up period of 64 +/- 31 months. Operation and fluoroscopic times were longer in DDD pacemaker implantation compared to VDD and VVI devices:58 +/- 23 versus 39 +/- 10 and 37 +/- 13 minutes (P<0.001), 9.2 +/- 5.2 versus 4.1 +/- 2.4 and 3.5 +/- 2.3 minutes, respectively. Differences remained significant after correction for covariates. In a multivariate Cox regression model, the corrected complication hazard of a DDD pacemaker implantation was increased by 3.9 (1.4-11.3) compared to VVI and increased by 2.3 (1.1-4.5) compared to VDD pacing. Higher complication rates in DDD pacing were mainly due to a higher incidence of early reoperation for atrial lead dysfunction, whereas the long-term complication rate was not different from VDD or VVI pacing. Early and long-term complication rates did not differ between VDD and VVI pacemaker systems. In conclusion, operation time and complication rates of physiological pacing are reduced by VDD pacemaker implantation achieving values comparable to VVI pacing. Thus, single lead VDD pacing can be recommended for patients with AV block.

With the benefit of a simpler implant procedure, long-term outcome of single lead VDD pacing is equivalent to DDD pacing in patients with AV block and preoperative normal sinus node function.

No abstract