ZOLL E Series Monitor Defibrillator Rev R - Manual (Page 121)

9650-1210-01 Rev. R A-23
between the two waveforms were considered statistically significant when the 95% confidence interval between the
two waveforms was greater than 0%.
Results: The study population of 165 patients had a mean age of 66±12 years with 116 male patients.
The total efficacy of consecutive rectilinear biphasic shocks was significantly greater than that of monophasic shocks.
The following table displays the Kaplan-Meier (product-limit) survival curves for each of the two waveforms. As all
patients begin in the failure mode, the estimated life-table probabilities refer to the chance of still being in failure after
the kth shock (k=1,2,3,4):
As can be seen from the table, the biphasic experience is superior over the entire course of shocks delivered. The one
degree of freedom chi-square statistic for the Mantel-Haenszel test is 30.39 (p<0.0001). Similarly, the log-rank test,
also a one degree of freedom chi-square statistic, is 30.38 (p<0.0001). The residual number of patients not
successfully treated after four shocks is 5.7% for biphasic compared to 20.8% for monophasic.
There was a significant difference between the first shock efficacy of biphasic shocks at 70 J of 68% and that of
monophasic shocks at 100 J of 21% (p=0.0001, 95% confidence interval of the difference of 34.1% to 60.7%).
Successful cardioversion with rectilinear biphasic shocks was achieved with 48% less delivered current than with
monophasic shocks (11 ±1 vs. 21 ±4 A, p<0.0001).
One half of the patients who failed cardioversion after four consecutive escalating monophasic shocks were
subsequently successfully cardioverted using a biphasic shock at 170 J. No patient was successfully cardioverted
using a 360 J monophasic shock after the patient had failed cardioversion with biphasic shocks.
Conclusion: The data demonstrate the superior efficacy of low energy rectilinear biphasic shocks compared to high
energy monophasic shocks for transthoracic cardioversion of atrial fibrillation. There were no unsafe outcomes or
adverse events due to the use of Rectilinear Biphasic Waveform.
Synchronized Cardioversion of Atrial Fibrillation
Cardioversion of atrial fibrillation (AF) and overall clinical effectiveness is enhanced by proper pad placement. Clinical
studies (refer to above) of the M Series Biphasic Defibrillator Waveform demonstrated that high conversion rates are
achieved when defibrillation pads are placed as shown in the diagram below.
Place the front (apex) pad on the third intercostal space, mid clavicular line on the right anterior chest. The back/
posterior pad should be placed in the standard posterior position on patient’s left as shown.
Shock # Kaplan-Meier Estimate for the Probability of Shock Failure
Biphasic Monophasic
0 1.000 1.000
1 0.318 0.792
2 0.147 0.558
3 0.091 0.324
4 0.057 0.208
Recommended Anterior/Posterior Placement
Back/
Posterior Front/
Apex