MEDEST

New 2025 Guidelines on Cardiopulmonary Resuscitation stated that alternative strategy for defibrillation of persistent VF/pVT are not yet ready for prime line based on the actual available evidences.

Previously ILCOR stated about the same topic: We suggest that a double sequential defibrillation strategy (weak recommendation, low certainty of evidence) or a vector change defibrillation strategy (weak recommendation, very low certainty of evidence) may be considered for adults with cardiac arrest who remain in ventricular fibrillation or pulseless ventricular tachycardia after 3 or more consecutive shocks.

So AHA degraded the ILCOR “may be considered to a “non useful” despite the same level of grade and evidences. Let’s see why and why THIS IS WRONG

AHA: It found significant improvement in survival at hospital discharge with VC and DSED compared to standard defibrillation by intention-to-treat, but notably not when trial findings were analyzed by the treatment strategy patients actually received

In summary, AHA highlighted one point for not suggesting VC or DSED over standard defibrillation. The reason is that the DOSE VF trial did not show any statistically relevant advantage in “per protocol analysis”!

I’m not a methodologist but I think that any of them can suffer of an heart attack hearing this statement! Intention to treat analysis is the core of randomization!

To summarize this concept here is a head to head compare between Intention to treat analysis VS per protocol analysis 

In randomized control trials, analyzing patients “per protocol” removes the advantages of randomization. This choice degrades the study results to an observational level. So AHA statement is incorrect and the trial results are highly relevant

AHA: Furthermore, in a secondary exploratory analysis a significant survival benefit from DSD was only observed in the 17% of study patients in whom VF was incessant, and not in the vast majority (83%) of patients in whom VF recurred after a successful shock.

You can find the cited secondary analysis here: The impact of alternate defibrillation strategies on shock-refractory and recurrent ventricular fibrillation: A secondary analysis of the DOSE VF cluster randomized controlled trial. And the following are the results:

Shock-Refractory VF (n. 60)

Shock-Recurrent VF (n. 285)

In both cases, recurrent or persistent, even if not always statistically significant, DSD and VC performed much better than standard defibrillation WITH RESULTS ABSOLUTELY CLINICALLY RELEVANT ON ALL MAJOR OUTCOMES

AHA: The interval between each sequential “double” shock required for successfully terminating VF has also been shown experimentally (animal studies 10-100 Mses) and demonstrated in DOSE-VF itself (mean interval 650 Mses. ) to require a level of precision (separated by milliseconds) unlikely to be consistently achievable by manual activation of two defibrillators. 

Th is totally wrong. The small ( 10- 100 Mses) cited from the guidelines refers to experimental animal study . DOSE-VF trial demonstrates statistically significant superiority to standard defibrillation. This superiority is observed with intervals >500 Msec that is absolutely replicable in clinical practice. The investigators also demonstrated the increase of advantages for shorter intervals. But, this increase is not seen at 10 Mses, which is only referred to in animal studies.

• DSED and VC are superior to standard defibrillation on every clinical relevant clinical outcome
• DSED and VC uphold clinical advantages on both persistent and recurrent VF/pVT
• When you chose DSED the interval between the 2 shocks is easily reproducible in clinical practice

In case of VF/pVT. First approach:

If recurrent or refractory VF/pVT

Tags: ACLS, ACR, arresto cardiaco, dual sequential defibrillition, emergency medicine, emergenza sanitaria territoriale, Guidelines, litterature review, medicina d'urgenza, medicina d'urgenza preospedaliera, refractory ventricular fibrillation, vector change defibrillation