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Intramyocardial Pacing and Sensing for the Enhancement of Cardiac Stimulation and Sensing Specificity
Author(s) -
ASIRVATHAM SAMUEL J,
BRUCE CHARLES J,
DANIELSEN ANDREW,
JOHNSON SUSAN B,
OKUMURA YASUO,
KATHMANN EVA,
PACKER DOUGLAS L,
FRIEDMAN PAUL A
Publication year - 2007
Publication title -
pacing and clinical electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.686
H-Index - 101
eISSN - 1540-8159
pISSN - 0147-8389
DOI - 10.1111/j.1540-8159.2007.00745.x
Subject(s) - medicine , intracardiac injection , ventricle , lead (geology) , cardiology , phrenic nerve , qrs complex , ventricular pacing , stimulation , biomedical engineering , heart failure , geomorphology , respiratory system , geology
Background:Intracardiac electrodes create an “antenna” capable of unintentionally recording and stimulating tissue beyond the chamber in which they are positioned, resulting in far‐field R wave oversensing in pacemakers and inappropriate detection in defibrillators. This feasibility study sought to determine whether a specially constructed lead with two distal totally intramyocardial electrodes could overcome these limitations.Methods:Two mongrel dogs were anesthetized and a median sternotomy performed. Epicardial intramyocardial pacing and sensing function was assessed and compared to standard active fixation pacing and sensing placed at the same atrial and ventricular sites. Right ventricular pacing was also assessed.Results:For the novel intramyocardial lead, the average R wave amplitude was 7.2 mV, compared to an average R wave of 8.4 mV for the standard active fixation lead placed at identical ventricular sites; P‐waves were also similar. Cross‐chamber sensing was present in the ventricle and atrium with the standard lead, and absent with the intramyocardial lead. The average pacing threshold was 0.7 mA at 0.2 ms for the novel lead compared to 1.1 mA for the standard lead. With the standard lead, phrenic stimulation was seen at threshold (cathode distal) and at 3 mA (cathode proximal electrode). No phrenic stimulation was seen with the novel intramyocardial lead despite outputs up to 20 mA at sites located 3–5 mm from the phrenic nerve.Conclusion:Totally intramyocardial pacing is feasible, and results in site‐specific pacing and sensing function. This may eliminate far‐field signal oversensing and phrenic stimulation in future devices.