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The Relationship Between Cardiac Vulnerability and Restitution Properties of the Ventricular Activation Recovery Interval
Author(s) -
YAMASHITA SOICHIRO,
YOSHIDA AKIHIRO,
FUKUZAWA KOJI,
NAKANISHI TOMOYUKI,
MATSUMOTO AKINORI,
KONISHI HIROKI,
ICHIBORI HIROTOSHI,
HYOGO KIYOHIRO,
IMADA HIROSHI,
HIRATA KENICHI
Publication year - 2015
Publication title -
journal of cardiovascular electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.193
H-Index - 138
eISSN - 1540-8167
pISSN - 1045-3873
DOI - 10.1111/jce.12672
Subject(s) - restitution , medicine , cardiology , ventricular fibrillation , anesthesia , law , political science
Upper Limit of Vulnerability and the APD Dynamics Introduction The restitution of the action potential duration (APD) is an important contributor to ventricular fibrillation (VF) initiation by a single critically timed ectopic beat. We hypothesized that a steep slope of the activation recovery interval restitution curve was related to the upper limit of vulnerability (ULV). Methods and Results Fifty‐four consecutive patients with implantable cardioverter defibrillators (ICDs) implanted between April 2012 and July 2013 were included. At the implantation, pacing from the right ventricular (RV) coil to an indifferent electrode inserted in the ICD pocket was performed, and the unipolar electrograms from the RV coil were simultaneously recorded. We assessed the standard restitution by introducing extra‐stimuli, while measuring the activation recovery interval (ARI). Our protocol for the vulnerability test consisted of delivering three 15 J shocks on the T‐peak and within ±20 milliseconds of it. If VF was not induced by that procedure, a ULV of ≤15 J was defined. The relationship between the ULV and maximum slope of the restitution curve was analyzed. A restitution curve could finally be obtained in a total of 40 patients. The background characteristics were similar between the two groups. The maximum slope of the restitution curve was steeper in the ULV > 15 J group than ULV ≤ 15 J group (1.55 ± 0.45 vs. 0.91 ± 0.64, P < 0.05). A maximum slope exceeding 1.0 was the optimal point for discriminating patients with a ULV > 15 J from a ULV ≤ 15 J (sensitivity 61.5% and specificity 96.3%). Conclusion The maximum slope of the restitution curve was significantly related to the ULV. High defibrillation threshold patients could be detected by the ARI dynamics.