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Long-term RV threshold behavior by automated measurements: safety is the standpoint of pacemaker longevity!
MedLine Citation:
PMID:  21029120     Owner:  NLM     Status:  In-Process    
BACKGROUND: We studied long-term right ventricular (RV) pacing threshold (RVPT) behavior in patients consecutively implanted with pacemakers capable of automatic output reprogramming tracked by automatic RV threshold measurement (automatic verification of capture [AVC]).
METHODS: All the patients had state-of-the art steroid-eluting bipolar pacing leads and were RV-paced by an AVC algorithm from the three American manufacturers. Follow-up occurred twice in the first year after implantation, then yearly until approaching elective replacement indicator.
RESULTS: Three hundred and twenty-one patients aged 73 ± 12 years were observed for 49 ± 26 months on average. At implantation, RVPT was 0.54 ± 0.2 V at 0.4 ms at an average 774 ± 217 Ω impedance. Forty-one of the 321 patients (12.8%) had a permanent RVPT increase above 1.5 V at 0.4 ms: RVPT was between 1.6 and 2.5 V in 29 of 321 (9%) patients, whereas it was between 2.6 and 3.5 V in seven of 321 (2.2%) patients, and >3.5 V in five of 321 (1.5%) patients. No exit block occurred because of automatic RV output adjustment by AVC algorithms. No predictor of RVPT increase was found at multivariable analysis. The maximum RVPT increase occurred within 12 months from implantation in 19 of 321 (5.9%) patients, between the first and the second year in 12 of 321 (3.7%), between the second and the sixth year in eight of 321 (2.5%), and after the sixth year in two of 321 (0.6%).
CONCLUSION: Despite technologic improvement in lead manufacturing, long-term increase of the RVPT occurs in about 13% of patients, possibly representing a serious safety issue in 3.7% when 2.5 V at 0.4 ms is exceeded. AVC algorithms can improve patients' safety by automatic tailoring of the pacing output to threshold fluctuations, while maximizing device longevity.
Mauro Biffi; Matteo Bertini; Andrea Mazzotti; Beatrice Gardini; Valentina Mantovani; Matteo Ziacchi; Cinzia Valzania; Christian Martignani; Igor Diemberger; Giuseppe Boriani
Publication Detail:
Type:  Journal Article     Date:  2010-10-01
Journal Detail:
Title:  Pacing and clinical electrophysiology : PACE     Volume:  34     ISSN:  1540-8159     ISO Abbreviation:  Pacing Clin Electrophysiol     Publication Date:  2011 Jan 
Date Detail:
Created Date:  2011-01-10     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7803944     Medline TA:  Pacing Clin Electrophysiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  89-95     Citation Subset:  IM    
Copyright Information:
©2010, The Authors. Journal compilation ©2010 Wiley Periodicals, Inc.
S.Orsola-Malpighi Hospital, Institute of Cardiology, University of Bologna, Bologna, Italy.
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