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Sequential Shocks are Comparable to Single Shocks Employing Two Current Pathways for Internal Defibrillation in Dogs
Author(s) -
WETHERBEE JULE N.,
CHAPMAN PETER D.,
BACH STANLEY M.,
TROUP PAUL J.
Publication year - 1988
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.1540-8159.1988.tb06019.x
Subject(s) - defibrillation , medicine , anode , electrode , cathode , superior vena cava , volt , defibrillation threshold , ventricular fibrillation , biomedical engineering , voltage , cardiology , electrical engineering , physics , quantum mechanics , engineering
Sequential pulse defibrillation using two current pathways was compared with single shocks simultaneously utilizing both pathways in 16 dogs to assess the effects of temporal summation. A cardioverter‐defibrillator catheter was positioned via the external jugular vein with the distal 4 cm 2 shocking electrode located in the right ventricular apex and the proximal 8 cm 2 electrode located in the superior vena cava. Three electrode configurations were tested(1) single pulse, distal electrode (cathode) to proximal electrode and chest wall patch (common anode), (2) sequential 5 ms pulses with 1 ms interpulse delay, distal electrode (cathode] to proximal electrode (anode) followed by distal electrode (cathode) to chest wall patch (anode), and (3] sequential 10 ms pulses with I ms interpulse delay using same current pathways described for configuration 2. The lowest energies resulting in termination of AC induced ventricular fibrillation on four trials were 27.9. 26.6, and 42.3 joules respectively for configurations 1, 2, and 3. The mean energy levels were not significantly different for configurations 1 and 2, both of which were significantly lower than that for configuration 3. The lowest peak voltages terminating ventricular fibrillation on four trials were 595 ± 176, 521 ± 134 and 579 ± 171 volts for configuration 1, 2, and 3. The mean voltage level for configuration 2 was significantly lower than that for configurations 1 and 3, which were not significantly different. The mean calculated impedance for the pathway utilizing the catheter was 74.6 ±13.7 ohms, for the pathway utilizing the distal catheter electrode to the chest wall electrode was 102.9 ± 19.7 ohms, and for simultaneous discharge employing both current pathways was 65.0 ±11.3 ohms. In conclusion, for the lead system tested, sequential pulses were not associated with lower energies than single pulses delivered through the same pathways and therefore, temporal summation is comparable to a single shock for internal defibrillation.