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High density endocardial mapping of shifts in the site of earliest depolarization during sinus rhythm and sinus tachycardia

High density endocardial mapping of shifts in the site of earliest depolarization during sinus rhythm and sinus tachycardia
High density endocardial mapping of shifts in the site of earliest depolarization during sinus rhythm and sinus tachycardia
Previous mapping studies of sinus rhythm suggest faster rates arise from more cranial sites within the lateral right atrium. In the intact, beating heart, mapping has been limited to epicardial plaques or single endocardial catheters. The present study was designed to examine shifts in the site of the earliest endocardial depolarization during sinus rhythm and sinus tachycardia using high density activation mapping. Noncontact mapping of the right atrium during sinus rhythm was performed on ten anesthetized swine. Recordings were made during sinus rhythm, phenylephrine infusion, and isoproterenol infusion. The hearts were then excised and the histological sinus node identified. The mean minimum and maximum cycle lengths recorded were355 ± 43and717 ± 108 ms. A median of three (range two to five) sites of earliest endocardial depolarization were documented in each animal. With increasing heart rate the site of earliest endocardial depolarization remained stationary until a sudden shift in a cranial or caudal direction, often to sites beyond the histological sinoatrial node. The endocardial shift was unpredictable with considerable variation between animals; however, faster rates arose from more cranial sites(r = 0.46, P = 0.023). There was no difference in the mean cycle length of sinus rhythm originating from specific positions on the terminal crest(r = 0.44, P = 0.17). Cranial sites displayed a more diffuse pattern of early depolarization than caudal sites. In the porcine heart the relationship between heart rate and site of earliest endocardial depolarization shows considerable variation between individual animals. These findings may have implications for clinical mapping and ablation procedures.
874-882
Betts, Tim R.
deac7746-b99a-4316-a312-16a3e43ab0ec
Roberts, Paul R.
193431e8-f9d5-48d6-8f62-ed9052b2571d
Ho, Siew Yen
2183d00f-cdd7-4c3c-81ac-d10dfe2b5d62
Morgan, John M.
ac98099e-241d-4551-bc98-709f6dfc8680
Betts, Tim R.
deac7746-b99a-4316-a312-16a3e43ab0ec
Roberts, Paul R.
193431e8-f9d5-48d6-8f62-ed9052b2571d
Ho, Siew Yen
2183d00f-cdd7-4c3c-81ac-d10dfe2b5d62
Morgan, John M.
ac98099e-241d-4551-bc98-709f6dfc8680

Betts, Tim R., Roberts, Paul R., Ho, Siew Yen and Morgan, John M. (2003) High density endocardial mapping of shifts in the site of earliest depolarization during sinus rhythm and sinus tachycardia. Pacing and Clinical Electrophysiology, 26 (4 Pt 1), 874-882. (doi:10.1046/j.1460-9592.2003.t01-1-00153.x).

Record type: Article

Abstract

Previous mapping studies of sinus rhythm suggest faster rates arise from more cranial sites within the lateral right atrium. In the intact, beating heart, mapping has been limited to epicardial plaques or single endocardial catheters. The present study was designed to examine shifts in the site of the earliest endocardial depolarization during sinus rhythm and sinus tachycardia using high density activation mapping. Noncontact mapping of the right atrium during sinus rhythm was performed on ten anesthetized swine. Recordings were made during sinus rhythm, phenylephrine infusion, and isoproterenol infusion. The hearts were then excised and the histological sinus node identified. The mean minimum and maximum cycle lengths recorded were355 ± 43and717 ± 108 ms. A median of three (range two to five) sites of earliest endocardial depolarization were documented in each animal. With increasing heart rate the site of earliest endocardial depolarization remained stationary until a sudden shift in a cranial or caudal direction, often to sites beyond the histological sinoatrial node. The endocardial shift was unpredictable with considerable variation between animals; however, faster rates arose from more cranial sites(r = 0.46, P = 0.023). There was no difference in the mean cycle length of sinus rhythm originating from specific positions on the terminal crest(r = 0.44, P = 0.17). Cranial sites displayed a more diffuse pattern of early depolarization than caudal sites. In the porcine heart the relationship between heart rate and site of earliest endocardial depolarization shows considerable variation between individual animals. These findings may have implications for clinical mapping and ablation procedures.

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Published date: 2003

Identifiers

Local EPrints ID: 25257
URI: https://eprints.soton.ac.uk/id/eprint/25257
PURE UUID: e779b7cb-fc5a-44ba-963d-ea80025c2406

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Date deposited: 06 Apr 2006
Last modified: 15 Jul 2019 19:16

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Contributors

Author: Tim R. Betts
Author: Paul R. Roberts
Author: Siew Yen Ho
Author: John M. Morgan

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