Predictive value of amplitude spectrum area of ventricular fibrillation waveform in patients with acute or previous myocardial infarction in out-of-hospital cardiac arrest

Abstract

The prognostic value of AMSA is altered by the presence of STEMI: while AMSA has strong predictive value in patients without STEMI, AMSA is not a predictor of survival in STEMI-patients.

Amplitude spectrum area: The “clairvoyance” during resuscitation in the era of predictive medicine

“…Indeed, the absence of rises in AMSA during CPR, despite increases in coronary perfusion pressure, was initially observed in animal models of cardiac arrest with concurrent STEMI and then confirmed in a small retrospective clinical database [11][12][13]. This potentially critical relationship has been now shown in the large ARREST registry [9]. How should we use this information?…”

“…In this issue of Resuscitation, Dr. Hulleman and colleagues have presented an elegant retrospective analysis of AMSA during CPR, aiming to investigate its association with the presence of acute ST-elevation myocardial infarction (STEMI), as cause of the outof-hospital cardiac arrest, and/or with previous MI and survival [9]. The study was performed in a large database including more than 700 patients from the ARREST (AmsteRdam REsuscitation STudies) prospective registry, which enrolls all resuscitation attempts in the North-Holland province of The Netherlands [10].…”

“…Thus, the primary endpoint of studies focusing on AMSA or other ECG-derived predictors, should be defibrillation outcome or at least ROSC, while relationship between AMSA and long term outcomes, i.e. hospital discharge as reported by Hulleman and colleagues [9], or 1-year survival and neurological recovery used by others [5,6], is probably not appropriate. Accordingly, a real-time AMSA analysis during CPR may be an effective tool to guide individual treatment and improve survival.…”

“…Unfortunately, data specifically on defibrillation outcome were not reported in Hulleman's article, making the capability of AMSA to predict defibrillation success in STEMI patients not evaluable [9]. Nevertheless, the results presented in this study represent the starting point to understand that, beside the relationship between AMSA and STEMI, many other potential confounding factors, able to lower or increase AMSA and eventually alter its predictive role, need to be acknowledged and investigated: duration of untreated cardiac arrest, quality of CPR, use of vasopressors, comorbidities and chronic drug treatments, etc [5,6,[13][14][15].…”

“…For this reason, additional uses of AMSA have been extrapolated, i.e. for identifying the presence of specific pathologies, like STEMI, although all the above conclusions derive, again, only from retrospective analyses with many limitations and selection biases [5,6,9,13]. Surprisingly, AMSA may become an almost complete clairvoyant during CPR, capable to predict not only defibrillation success but also comorbidities, drug assumptions, and even more, such as long term survival and neurological outcome.…”