title: Improvement of cardiac function by increasing stimulus strength during left ventricular pacing in cardiac resynchronization therapy.
abstract: Cardiac resynchronization therapy (CRT) is an established therapy in patients with severe heart failure due to left ventricular (LV) dyssynchrony. Increasing stimulus strength (SS) of LV pacing could capture an enlarged myocardial area and provide rapid electrical conduction. The aim of the present study was to investigate whether increasing SS of LV pacing improves LV mechanical dyssynchrony and cardiac function in patients treated with CRT.We enrolled 26 patients with CRT and changed the SS of LV pacing: 2.5 V (standard SS) and 5 V (high SS). Electrocardiography and echocardiography were performed to assess QRS duration, LV mechanical dyssynchrony, and cardiac function under each condition.The QRS duration (138.6 ± 21.4 ms versus 126.8 ± 23.1 ms, P < 0.001), septal-posterior wall motion delay (126.5 ± 42.7 ms versus 111.4 ± 55.3 ms, P = 0.012), standard deviation of time from QRS (69.6 ± 21.8 ms versus 55.6 ± 19.4 ms, P < 0.001), LV ejection fraction (29.4 ± 10.6% versus 33.4 ± 11.6%, P = 0.005), and LV stroke volume (50.7 ± 15.5 mL versus 63.8 ± 18.3 mL, P < 0.001) improved significantly in high SS compared with standard SS.Increasing SS of LV pacing in CRT improves LV mechanical dyssynchrony and cardiac function. The capture of an enlarged myocardial area by increasing SS of LV pacing might offer an acute hemodynamic benefit to patients treated with CRT.
authors.affiliation: Department of Cardiovascular Medicine, Wakayama Medical University.
authors.forename: Kohei
authors.initials: K
authors.lastname: Ishibashi
authors.forename: Takashi
authors.initials: T
authors.lastname: Kubo
authors.forename: Hironori
authors.initials: H
authors.lastname: Kitabata
authors.forename: Shigeho
authors.initials: S
authors.lastname: Takarada
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Shimamura
authors.forename: Takashi
authors.initials: T
authors.lastname: Tanimoto
authors.forename: Makoto
authors.initials: M
authors.lastname: Orii
authors.forename: Yasutsugu
authors.initials: Y
authors.lastname: Shiono
authors.forename: Takashi
authors.initials: T
authors.lastname: Yamano
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Ino
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Yamaguchi
authors.forename: Kumiko
authors.initials: K
authors.lastname: Hirata
authors.forename: Atsushi
authors.initials: A
authors.lastname: Tanaka
authors.forename: Toshio
authors.initials: T
authors.lastname: Imanishi
authors.forename: Takashi
authors.initials: T
authors.lastname: Akasaka
mesh_terms: D000368:Aged; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D003627:Data Interpretation, Statistical; D004452:Echocardiography; D004558:Electric Stimulation / Q000379:methods; D004562:Electrocardiography; D005260:Female; D006333:Heart Failure / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D016277:Ventricular Function, Left