[en] Life is a journey sometimes interrupted in a sudden and unexpected way. In 40% of sudden out-of-hospital cardiac arrest (OHCA) cases the initially recorded heart rhythm is ventricular fibrillation (VF). The only effective way to treat VF is by procuring a defibrillating electrical shock to the heart. In an out-of-hospital setting, the shock is delivered using an automated external defibrillator (AED), a device capable of analyzing the victim's electrocardiogram (ECG)to detect if a shockable rhythm is present. Survival from OHCA depends largely on two factors: early defibrillation and early cardiopulmonary resuscitation (CPR), which prolongs the window of opportunity for defibrillation. CPR must be stopped for a reliable AED rhythm analysis because chest compressions introduce artifacts in the ECG. Unfortunately, interrupting CPR adversely affects defibrillation success. The use of AEDs in 1 to 8 year olds was approved in 2003. AEDs, which were originally designed for adult patients, must accurately discriminate pediatric arrhythmias to be safely used in children. Several AEDs have been adapted for pediatric use, either by demonstrating that existing adult algorithms accurately diagnose pediatric arrhythmias or by creating specific algorithms to diagnose pediatric arrhythmias. This thesis presents a new AED algorithm designed for adult and pediatric patients together. The algorithm is thoroughly tested using pediatric and adult arrhythmia databases compliant with the American Heart Association (AHA) statements, and on real resuscitation data with and without CPR artifacts. The work started with a long experimental phase in which 1090 pediatric rhythms were retrospectively collected and classified to create a comprehensive database of pediatric arrhythmias. Additionally, an existing adult database was revised and 928 new adult rhythms were collected and classified. The complete dataset is composed of 2782 registers, 1270 were used to develop the algorithm and 1512 to test it. Then, a new AED shock advice algorithm composed of four subalgorithms was designed. These sub-algorithms are based on a set of new arrhythmia detection features derived from several signal domains such as time, frequency, slope or the autocorrelation function. The algorithm exceeded the AHA performance goals for the detection of shockable and non-shockable rhythms both on adult and pediatric arrhythmias. The work concluded with the analysis of the performance of the algorithm for real resuscitation data extracted from a comprehensive database of OHCA episodes. All AHA performance goals were met for artifact-free OHCA rhythms. Then, the performance of the algorithm during chest compressions was assessed, before and after the suppression of the CPR artifact. The CPR artifact was suppressed using a new methodology developed as part of this thesis work. Although shockable rhythms were accurately identified after filtering, non-shockable rhythms were not.

[eu] Bizitza bidaia da, batzuetan bat-batean eta ezustean eteten den bidaia. Ospitaletik kanpo gertatzen diren bat-bateko bihotz-biriketako geldiketa-kasuen %40an lehendabizi grabatutako bihotz-erritmoa fibrilazio bentrikularra (FB) da. Bihotzean desfibrilazioa eragingo duen deskarga elektrikoa ematea da FBa tratatzeko modu eraginkor bakarra. Ospitaletik at, kanpoko desfibrilagailu automatikoa (KDA) erabiltzen da deskarga emateko, pazientearen elektrokardiograma (EKG) aztertu eta desfibrilagarriak diren erritmoak detektatzeko gaitasuna duen aparagailua, alegia. Kasu horietan, biziraupena bi faktore hauen menpekoa da: desfibrilazio goiztiarraren menpekoa eta bihotz-biriketako berpizte (BBB) goiztiarraren menpekoa (desfibrilazioa emateko aukera-lehioa luzatzen duena). BBBan ematen diren bular-sakadek interferentzia sortzen dute EKGan; ondorioz, BBBa gelditu behar da KDAk bihotz erritmoa egokiro azter dezan. Tamalez, geldiketa horiek desfibrilazioaren arrakasta maila txikiagotzen dute. KDA-aren erabilera 1 eta 8 urte bitarteko umeekin 2003an onartu zen. Ordura arte paziente helduak tratatzeko diseinatutako KDAk modu zehatzean identifikatu behar dituzte arritmia pediatrikoak, umeekin erabili ahal izateko. Zenbait KDA umeekin erabiltzeko egokitu dira, bi eratara: helduekin erabiltzen diren algoritmoak umeekin ere zehatzak direla frogatuz, eta umeen arritmiak identikatzeko algoritmo bereziak erabiliz. Tesi honetan KDA algoritmo berri bat garatu da, diseinua paziente heldu eta pediatrikoekin batera eginez. Algoritmoa sakon egiaztatu da. Batetik, American Heart Association (AHA) erakundeak ezarritako baldintzak betetzen dituzten helduen eta umeen arritmia datu-baseak erabiliz, eta, bestetik, bihotz-geldiketetan grabatutako arritmiak erabiliz, BBB interferentziaz kutsatutako eta interferentziarik gabeko kasuetan. Tesi-lana atal experimental luze batekin hasi zen. Fase horretan 1090 arritmia pediatriko bildu eta klasifikatu ziren, arritmia pediatrikoen datu-base zabal bat sortuz. Horrez gain, helduen datu-base oso bat berraztertu eta 928 helduen arritmia berri bildu eta klasifikatu ziren. Datu-base osoak 2782 erregistro ditu: 1270 algoritmoa garatzeko erabili ziren eta 1512 algoritmoa egiaztatzeko. Ondoren, lau azpialgoritmoz osatutako algoritmo berria garatu zen. Azpialgoritmoek seinalearen zebait eremutan kalkulatutako parametro berriak erabiltzen dituzte arritmiak etektatzeko; adibidez, denbora, maiztasuna, pendiza edo autokorrelazio-funtzioa. Algoritmo berriak AHAk ezarritako mailak gainditzen ditu erritmo desfibrilagarri eta ez-desfibrilagarriak detektatzeko, paziente pediatriko zein helduekin. Lanaren azken atalean, algoritmo berriak bihotz-geldiketan grabatutako erregistroak identifikatzeko duen ahalmena aztertu zen. BBB interferentziarik gabeko erritmoetan, algoritmoak AHAk ezarritako mailak gainditzen ditu. Ondoren, erritmoak aztertu ziren bular-sakadak ematen ziren bitartean, BBB interferentzia ezabatu aurretik eta ezabatu ondoren. Interferentzia ezabatzeko, tesian zehar garatutako metodo berri bat erabili zen. BBB interferentzia ezabatu ondoren, erritmo desfibrilagarriak modu zehatzean identifikatu ziren; erritmo ez-desfibrilagarriak, ez.