Impact of moderate exercise workload on predicted optimal AV and VV delays determined by an intracardiac electrogram-based method for optimizing cardiac resynchronization therapy.

AIMS: Aim of this study is to evaluate reproducibility, consistency and the impact of moderate exercise workload on optimized PV and VV delays as determined by the IEGM-based QuickOpt™ method (St. Jude Medical), that was shown to produce hemodynamic performance similar to that obtained by echo-guided aortic VTI maximization. METHODS: Sixty patients with CRT-ICD (65 ± 9 years, 12% female, LVEF 28 ± 9%, 48% CAD and 52% DCM) were enrolled. IEGM-based PV/VV optimization was conducted six times: twice at rest, twice immediately after a 6-min walk test and twice following a 3-min recovery period. Timing cycle delays were programmed in accordance with the optimization results. Follow-up was performed after 1 year. RESULTS: Although significant difference in heart rate was reached [68 ± 9 bpm (REST) vs. 79 ± 12 (6MWT), p < 0.001], differences were not observed between IEGM-based optimized PV/VV delays: PV(opt) = 128 ± 14 ms (REST) versus 130 ± 17 ms (6MWT) versus 129 ± 16 ms (RECOV); VV(opt) = 15 ± 24 ms (REST) versus 15 ± 22 ms (6MWT) versus 16 ± 24 ms (RECOV). During 1-year follow-up PV(opt) and VV(opt) remained stable (ΔPV(opt) = 10 ± 10 ms, ΔVV(opt) = 9 ± 11 ms). CONCLUSION: Optimized IEGM-based timing cycle delays are independent of moderate exercise status within a particular patient but varied between patients. This supports the use of PV/VV optimization in each CRT patient.

Impact of left ventricular lead position on the incidence of ventricular arrhythmia and clinical outcome in patients with cardiac resynchronization therapy.

PURPOSE: The aim of the study was to evaluate the incidence of ventricular arrhythmia and clinical outcome in patients receiving a cardiac resynchronization therapy (CRT) depending on the left ventricular (LV) lead position. METHODS: A total of 187 consecutive patients with advanced heart failure who received a CRT-implantable cardioverter defibrillator were analyzed. Forty patients (21%) had a LV lead in the anterior/apical (anterior) and 147 patients (79%) in the posterior/posterolateral (posterior) region. The total median follow-up time was 644 days. RESULTS: The incidence of ventricular arrhythmia was 35% in patients with an anterior LV lead versus 30% in patients with a posterior LV lead (p = 0.53). The 1- and 2-year mortality in the anterior LV lead group was 19% and 22%, as compared with 0.7% and 3.2%, respectively, in the posterior LV lead group (p < 0.001). In a multivariable analysis, an anterior LV lead was independently associated with an increased mortality (hazard ratio 5.88, 95% confidence interval 2.22-16.67). The major cause of death was end-stage heart failure whereas the incidence of sudden cardiac death was not different between both groups. CONCLUSIONS: Thus, biventricular pacing with an anterior LV lead seems to have no impact on the incidence of ventricular arrhythmia but may be associated with an increased mortality rate due to worsening heart failure.

Prevalence of bacterial colonization of generator pockets in implantable cardioverter defibrillator patients without signs of infection undergoing generator replacement or lead revision.

AIMS: This study was designed to evaluate the prevalence of bacterial colonization of generator pockets in implantable cardioverter defibrillator (ICD) patients without signs of infection and to analyse the impact of bacterial colonization on the incidence of device infection during follow-up. METHODS AND RESULTS: In 122 ICD patients undergoing generator replacement or surgical lead revision between January 2006 and July 2008, microbiological cultures of generator pockets and extracted leads were consecutively obtained. Patients with clinical evidence of a device infection were excluded. Positive cultures from the generator pocket and leads were found in 40 (33%) patients. The most common bacteria isolated were coagulase negative staphylococci (68%). During a median follow-up time of 203 days after the revision device infection occurred in three [7.5%, confidence interval (CI) 1.6-20.4%] patients with a positive culture vs. two (2.4%, CI 0.3-8.5%) patients with a negative culture (P = 0.33). Time from revision to infection was 108 +/- 73 days in patients with positive culture vs. 60 +/- 39 days in patients with negative culture (P = 0.50). CONCLUSION: A third of ICD patients undergoing generator replacement or lead revision have an asymptomatic bacterial colonization of generator pockets. After revision 7.5% of these patients develop a device infection with the same species of microorganism.