Postextrasystolic Contractility Normally Decays in Alternans in Canine In Situ Heart

Juichiro Shimizu; Satoshi Mohri; Gentaro Iribe; Yutaka Kitagawa; Haruo Ito; Junichi Araki; Miyako Takaki; Hiroyuki Suga

doi:10.2170/jjphysiol.53.313

Postextrasystolic Contractility Normally Decays in Alternans in Canine In Situ Heart

Juichiro Shimizu, Satoshi Mohri, Gentaro Iribe, Yutaka Kitagawa, Haruo Ito, Junichi Araki, Miyako Takaki, Hiroyuki Suga

Research output: Contribution to journal › Article › peer-review

3 Citations (Scopus)

Abstract

We have reported that the postextrasystolic (PES) potentiation of left ventricular (LV) contractility usually decays in alternans at heart rates above 80-100beats/min in the canine excised, cross-circulated heart. We examined whether the PES contractility would also decay in alternans even in the canine in situ heart presumably more physiological than the excised heart. In anesthetized, ventilated, and open-chest mongrel dogs, we measured LV pressure and volume with a micromanometer and a conductance catheter cannulated into the LV and obtained LV end-systolic maximum elastance (E_max) as the reasonably load-independent contractility index. We inserted an extrasystole followed by a compensatory pause into steady-state regular beats at heart rates above 90beats/min and analyzed the PES decay pattern of E_max. We found that E_max potentiated in the first PES beat decayed in alternans within 5-6 PES beats. This indicates that PES contractility also decays in alternans in the normal canine in situ heart.

Original language	English
Pages (from-to)	313-318
Number of pages	6
Journal	Japanese journal of physiology
Volume	53
Issue number	4
DOIs	https://doi.org/10.2170/jjphysiol.53.313
Publication status	Published - Aug 2003
Externally published	Yes

Keywords

Arrhythmia
Ca recirculation
Compensatory pause
E
Pressure-volume loop

ASJC Scopus subject areas

Physiology

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title = "Postextrasystolic Contractility Normally Decays in Alternans in Canine In Situ Heart",

abstract = "We have reported that the postextrasystolic (PES) potentiation of left ventricular (LV) contractility usually decays in alternans at heart rates above 80-100beats/min in the canine excised, cross-circulated heart. We examined whether the PES contractility would also decay in alternans even in the canine in situ heart presumably more physiological than the excised heart. In anesthetized, ventilated, and open-chest mongrel dogs, we measured LV pressure and volume with a micromanometer and a conductance catheter cannulated into the LV and obtained LV end-systolic maximum elastance (Emax) as the reasonably load-independent contractility index. We inserted an extrasystole followed by a compensatory pause into steady-state regular beats at heart rates above 90beats/min and analyzed the PES decay pattern of Emax. We found that Emax potentiated in the first PES beat decayed in alternans within 5-6 PES beats. This indicates that PES contractility also decays in alternans in the normal canine in situ heart.",

keywords = "Arrhythmia, Ca recirculation, Compensatory pause, E, Pressure-volume loop",

author = "Juichiro Shimizu and Satoshi Mohri and Gentaro Iribe and Yutaka Kitagawa and Haruo Ito and Junichi Araki and Miyako Takaki and Hiroyuki Suga",

year = "2003",

month = aug,

doi = "10.2170/jjphysiol.53.313",

language = "English",

volume = "53",

pages = "313--318",

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T1 - Postextrasystolic Contractility Normally Decays in Alternans in Canine In Situ Heart

AU - Shimizu, Juichiro

AU - Mohri, Satoshi

AU - Iribe, Gentaro

AU - Kitagawa, Yutaka

AU - Ito, Haruo

AU - Araki, Junichi

AU - Takaki, Miyako

AU - Suga, Hiroyuki

PY - 2003/8

Y1 - 2003/8

N2 - We have reported that the postextrasystolic (PES) potentiation of left ventricular (LV) contractility usually decays in alternans at heart rates above 80-100beats/min in the canine excised, cross-circulated heart. We examined whether the PES contractility would also decay in alternans even in the canine in situ heart presumably more physiological than the excised heart. In anesthetized, ventilated, and open-chest mongrel dogs, we measured LV pressure and volume with a micromanometer and a conductance catheter cannulated into the LV and obtained LV end-systolic maximum elastance (Emax) as the reasonably load-independent contractility index. We inserted an extrasystole followed by a compensatory pause into steady-state regular beats at heart rates above 90beats/min and analyzed the PES decay pattern of Emax. We found that Emax potentiated in the first PES beat decayed in alternans within 5-6 PES beats. This indicates that PES contractility also decays in alternans in the normal canine in situ heart.

AB - We have reported that the postextrasystolic (PES) potentiation of left ventricular (LV) contractility usually decays in alternans at heart rates above 80-100beats/min in the canine excised, cross-circulated heart. We examined whether the PES contractility would also decay in alternans even in the canine in situ heart presumably more physiological than the excised heart. In anesthetized, ventilated, and open-chest mongrel dogs, we measured LV pressure and volume with a micromanometer and a conductance catheter cannulated into the LV and obtained LV end-systolic maximum elastance (Emax) as the reasonably load-independent contractility index. We inserted an extrasystole followed by a compensatory pause into steady-state regular beats at heart rates above 90beats/min and analyzed the PES decay pattern of Emax. We found that Emax potentiated in the first PES beat decayed in alternans within 5-6 PES beats. This indicates that PES contractility also decays in alternans in the normal canine in situ heart.

KW - Arrhythmia

KW - Ca recirculation

KW - Compensatory pause

KW - E

KW - Pressure-volume loop

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Postextrasystolic Contractility Normally Decays in Alternans in Canine In Situ Heart

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Keywords

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