ZOLL X Series Monitor Defibrillator Rev H - Manual (Page 313)

Clinical Trial Results for the Biphasic Waveform
9650-001355-01 Rev. H X Series Operator’s Guide A-27
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 k
th
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 70J of
68% and that of monophasic shocks at 100J 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 170J. No patient
was successfully cardioverted using a 360J 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.
Table A-3. Kaplan-Meier Estimate for the Probability of Shock Failure
Shock # 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