A novel ex vivo heart model for the assessment of cardiac pacing systems.
J Biomech Eng
; 127(6): 894-8, 2005 Nov.
Article
in En
| MEDLINE
| ID: mdl-16438224
ABSTRACT
BACKGROUND:
Advances in endocardial device design have been limited by the inability to visualize the device-tissue interface. The purpose of this study was to assess the validity of an isolated heart approach, which allows direct ex vivo intracardiac visualization, as a research tool for studying endocardial pacing systems. METHOD OFAPPROACH:
Endocardial pacing leads were implanted in the right atria and ventricles of intact swine (n = 8) under fluoroscopic guidance. After collection of pacing and sensing performance parameters, the hearts were excised with the leads intact and reanimated on the isolated heart apparatus, and parameters again recorded.RESULTS:
Atrial ex vivo parameters significantly decreased compared with in vivo measurements P-wave amplitudes by 39%, slew rates by 61%, and pacing impedances by 42% (p < 0.05 for each). Similarly, several ventricular ex vivo parameters decreased R-wave amplitudes by 39%, slew rates by 62%, and pacing impedances by 31%. In contrast, both atrial (4.4 +/- 2.8 vs 3.3 +/- 2.8 V; p = ns) and ventricular thresholds increased (1.2 +/- 0.7 vs 0.6 +/- 0.1 V; p < 0.05 for all). Three distinct phenomena were observed at the lead-tissue interface. Normal implants (70%) demonstrated minimal tissue distortion and resulted in elevated impedance and threshold values. Three implants (13%) resulted in severe tissue distortion and/or tissue wrapping and were associated with highly elevated pacing parameters. Tissue coring occurred in four implants (17%) where the lead would spin freely in the tissue after overtorquing of the lead.CONCLUSIONS:
The utility of the isolated heart approach was demonstrated as a tool for the design and assessment of the performance of endocardial pacing systems. Specifically, the ability to visualize device-heart interactions allows new insights into the impact of product design and clinical factors on lead performance and successful implantation.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Pacemaker, Artificial
/
Equipment Failure Analysis
/
Models, Animal
/
Electrocardiography
/
Electrodes, Implanted
/
Heart Conduction System
Type of study:
Guideline
/
Health_technology_assessment
/
Prognostic_studies
Limits:
Animals
Language:
En
Journal:
J Biomech Eng
Year:
2005
Document type:
Article
Affiliation country:
United States