<HTML><BODY style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; "><DIV><DIV style="text-align: justify;margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Arial" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;">Dear Miguel Angel Sanchez Verduzco from Guadalajara Jalisco Mexico. Here Andrés Ricardo Pérez Riera from Sao Paulo Brazil answer.</SPAN></FONT></DIV><DIV style="text-align: justify;margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Arial" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;"><B>Sudden death</B></SPAN></FONT><FONT class="Apple-style-span" face="Arial" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;"> (SD) is defined as a death that occurs suddenly, develops during an unpredictable course, and is due to natural or unnatural causes. Although there is no universally standardized definition on how "sudden" a SD is, WHO defines SD as a death that occurs within 24 hours after the onset of symptoms.</SPAN></FONT></DIV><P align="justify" style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "> </P><DIV style="text-align: justify;margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Arial" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;"><B>Sudden Cardiac Death</B></SPAN></FONT><FONT class="Apple-style-span" face="Arial" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;"> (SCD) is defined as unexpected natural death due to cardiac causes, heralded by abrupt loss of consciousness within one hour after the onset of symptoms in a person without any prior condition that would appear fatal(1). SCD is the sudden, abrupt loss of heart function (ie, cardiac arrest) in a person who may or may not have been diagnosed with heart disease. The time and mode of death are unexpected. It occurs instantly or shortly after the onset of symptoms. Out-of-hospital SCD is a frequent cause of death. Survival rates remain low despite increasing efforts in medical care. Recently information on cases of out-of-hospital SCD was collected in the Berlin, Germany, and emergency medical system via a questionnaire by Muller et al.(2) Bystander interviews were performed by the emergency physician on scene immediately after declaration of death or return of circulation. Of 5831 rescue missions, 406 involved patients with presumed cardiac arrest. 66% had a known cardiac disease. In 72%, the arrest occurred at home, and in 67%, it occurred in the presence of an eyewitness. Information on symptoms immediately preceding the arrest was available in 80% of all 406 patients. Typical angina was present for a median of 120 minutes in 25% of the 274 patients with witnessed arrest and in 33% with a symptom duration of less than 1 hour. The authors conclude that SCD occurs most often at home in the presence of relatives and after a longer period of typical warning symptoms. Although the much-hailed use of public access external defibrillation is supported by several studies, the present results raise the question of whether educational measures and targeted educational programs tailored for patients at risk and their relatives should have a higher priority.</SPAN></FONT></DIV><DIV style="text-align: justify;margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Arial" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;"> SCD is a dramatic and/or spontaneous death that is thought to be (and usually is) caused by a heart condition and may have been brought on by exercise.</SPAN></FONT></DIV><DIV style="text-align: justify;margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Arial" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;">The mechanisms of SCD are the following: 1)</SPAN></FONT><FONT class="Apple-style-span" face="Times New Roman" size="2"><SPAN class="Apple-style-span" style="font-size: 9.3px;"> </SPAN></FONT><FONT class="Apple-style-span" face="Arial" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;">VF; 2)</SPAN></FONT><FONT class="Apple-style-span" face="Times New Roman" size="2"><SPAN class="Apple-style-span" style="font-size: 9.3px;"> </SPAN></FONT><FONT class="Apple-style-span" face="Arial" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;">VT and ventricular flutter with subsequent VF; 3)</SPAN></FONT><FONT class="Apple-style-span" face="Times New Roman" size="2"><SPAN class="Apple-style-span" style="font-size: 9.3px;"> </SPAN></FONT><FONT class="Apple-style-span" face="Arial" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;">TdP followed by VF; 4)</SPAN></FONT><FONT class="Apple-style-span" face="Times New Roman" size="2"><SPAN class="Apple-style-span" style="font-size: 9.3px;"> </SPAN></FONT><FONT class="Apple-style-span" face="Arial" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;">Bradyarrhythmias and 5)</SPAN></FONT><FONT class="Apple-style-span" face="Times New Roman" size="2"><SPAN class="Apple-style-span" style="font-size: 9.3px;"> </SPAN></FONT><FONT class="Apple-style-span" face="Arial" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;">Asystolic arrest.</SPAN></FONT></DIV><DIV style="text-align: justify;margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Arial" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;">White the main risk factor is the presence of coronary artery disease(CAD), any organic or functional disease of the heart can predispose for SCD. </SPAN></FONT></DIV><DIV style="text-align: justify;margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Arial" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;">SCD (also called sudden cardiac arrest (SCA) or cardiovascular collapse,) is death resulting from an abrupt loss of heart function. The victim may or may not have diagnosed heart disease. The time and mode of death are </SPAN></FONT><FONT class="Apple-style-span" face="Arial" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;"><I>unexpected</I></SPAN></FONT><FONT class="Apple-style-span" face="Arial" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;">. It occurs within 60 minutes after symptoms appear in a person with known or unknown cardiac disease in whom no previously diagnosed fatal condition is apparent. The most common underlying reason for patients to die suddenly from SCA is CHD.</SPAN></FONT></DIV><DIV style="text-align: justify;margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Arial" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;">Approximately half of all cardiac deaths can be classified as SCDs.</SPAN></FONT></DIV><DIV style="text-align: justify;margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Arial" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;">SCD occurs as the first expression of cardiac disease in many individuals presenting as out-of-hospital patients with SCA.</SPAN></FONT></DIV><DIV style="text-align: justify;margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Arial" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;">To evaluate the risk of SCD noninvasive (Holter, echocardiography, exercise test, SA-ECG, MTWA, and often invasive PES tests are necessary.</SPAN></FONT></DIV><DIV style="text-align: justify;margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Arial" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;">The therapy is based on drugs (mainly beta blockers and amiodarone), coronary revascularization, catheter ablation techniques and the implantation of a CDI. The latter appears to be the most promising approach(3).</SPAN></FONT></DIV><P align="justify" style="margin-top: 0px; margin-right: 0px; margin-bottom: 12px; margin-left: 0px; "><FONT class="Apple-style-span" face="Arial" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;"><B>Sudden Arrhythmia Death Syndrome </B></SPAN></FONT><FONT class="Apple-style-span" face="Arial" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;">(SADS) In about 1 in every 20 cases of SCD, no definite cause of death can be found, even after the heart has been examined by an expert cardiac pathologist. This is then called Sudden Arrhythmic Death Syndrome or SADS. (In the past it has also been called Sudden Adult Death Syndrome or Sudden Death Syndrome but, because it affects children too, the term Sudden Arrhythmic Death Syndrome is now used.) It is thought that cot death (Sudden Infant Death Syndrome, or SIDS) may be partly due to the same causes responsible for SADS.</SPAN></FONT></P><P align="justify" style="margin-top: 0px; margin-right: 0px; margin-bottom: 12px; margin-left: 0px; "><FONT class="Apple-style-span" face="Arial" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;">SADS is a disorder of the electrical system of the heart that can lead to the death of apparently healthy people without any warning. The condition is caused by dysfunction ion channels. These channels control the flow of ions like Ca++, Na+ and K+. The flow of these ions in and out of the cells produces the electrical activity of the heart. Abnormalities of these channels can be acquired or inherited. The acquired form is caused by certain medications or physiopatological conditions.</SPAN></FONT></P><P align="justify" style="margin-top: 0px; margin-right: 0px; margin-bottom: 12px; margin-left: 0px; "><FONT class="Apple-style-span" face="Arial" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;"><B>References</B></SPAN></FONT></P><DIV style="text-align: justify; text-indent: -24px;margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 48px; "><FONT class="Apple-style-span" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;">1)</SPAN></FONT><FONT class="Apple-style-span" face="Times New Roman" size="2"><SPAN class="Apple-style-span" style="font-size: 9.3px;"> </SPAN></FONT><FONT class="Apple-style-span" face="Arial" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;">Zheng ZJ, Croft JB, Giles WH, et al. Sudden cardiac death in the United States, 1989 to 1998. </SPAN></FONT><FONT class="Apple-style-span" face="Arial" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;"><I>Circulation. </I></SPAN></FONT><FONT class="Apple-style-span" face="Arial" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;">2001; 104: 2158–2163.</SPAN></FONT></DIV><DIV style="text-align: justify; text-indent: -24px;margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 48px; "><FONT class="Apple-style-span" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;">2)</SPAN></FONT><FONT class="Apple-style-span" face="Times New Roman" size="2"><SPAN class="Apple-style-span" style="font-size: 9.3px;"> </SPAN></FONT><FONT class="Apple-style-span" face="Arial" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;">Muller D, Agrawal R, Arntz HR. How sudden is sudden cardiac death? Circulation. 2006; 114:1146-1150.</SPAN></FONT></DIV><DIV style="text-align: justify; text-indent: -24px;margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 48px; "><FONT class="Apple-style-span" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;">3)</SPAN></FONT><FONT class="Apple-style-span" face="Times New Roman" size="2"><SPAN class="Apple-style-span" style="font-size: 9.3px;"> </SPAN></FONT><FONT class="Apple-style-span" face="Arial" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;">Evequoz D, Zuber M, Erne P.Sudden cardiac death: definition, mechanisms and risk factors Synonyms and related keyword: sudden arrest: Schweiz Rundsch Med Prax. 1996; 85:188-196.</SPAN></FONT></DIV><DIV style="text-align: justify; text-indent: -24px;margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 48px; "><FONT class="Apple-style-span" face="Arial" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;">All the best</SPAN></FONT></DIV><DIV style="text-align: justify; text-indent: -24px;margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 48px; "><FONT class="Apple-style-span" face="Arial" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;">Andrés Ricardo Pérez Riera</SPAN></FONT></DIV><DIV style="text-indent: 0px;text-align: justify; margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Arial" size="4"><SPAN class="Apple-style-span" style="font-size: 13.3px;">Chief of Electro-Vectocardiology Sector of the Discipline of Cardiology, ABC Faculty of Medicine (FMABC), Foundation of ABC (FUABC) - Santo André - Sao Paulo - Brazil. Rua Sebastiao Afonso 885 - Zip Code: 044417-100- Jardim Miriam S.P Brazil</SPAN></FONT></DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">--</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Dr. Sergio Dubner</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">President of Scientific Committee</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 13px/normal Lucida Grande; min-height: 16px; ; font-family: Lucida Grande; font-size: 13px; "><BR style="font-family: Lucida Grande; font-size: 13px; "></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Dr. Edgardo Schapachnik</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">President of Steering Committee</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV><BR class="khtml-block-placeholder"></DIV><BLOCKQUOTE type="cite"><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV> <DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Arial">I can't see hardly any complication, not even semantic, in what we consider cardiac arrest or better, cardiorespiratory arrest, whichever the cause. We may simply consider that any patient that requires cardiorespiratory reanimation is because he/she has: lack of effective cardiac output. </FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 13px/normal GB18030 Bitmap; min-height: 17px; "><FONT class="Apple-style-span" face="Arial" size="3"><SPAN class="Apple-style-span" style="font-size: 12px;"><BR></SPAN></FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Arial">Dr. Miguel Angel Sanchez Verduzco</FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Arial">medicina intensiva. Guadalajara jalisco México</FONT></DIV><FONT class="Apple-style-span" face="Arial"></FONT><DIV><BLOCKQUOTE type="cite"><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><FONT class="Apple-style-span" face="Arial"><BR></FONT></DIV> <DIV class="MsoNormal"><FONT class="Apple-style-span" face="Arial">From a certain point of view, cardiac arrest is the time of death, although we all know there is a margin between brain death, legally considered in many countries as "death" proper, and cardiac arrest or else, tachyarrythmias that condition low output. It would be necessary to differentiate also VT/VF from electrical activity with no pulse, or asystole as cause of death. We know that on many occasions, they are a continuum that we attempt to stop with different interventions that are variably successful according to the opportunity and efficacy. </FONT><FONT class="Apple-style-span" face="Arial"><O:P></O:P></FONT></DIV><DIV class="MsoNormal"><FONT class="Apple-style-span" face="Arial">From my personal point of view, the difference may be more semantic than practical, due to the great amount of variables to take into account: do we consider cardiac arrest as the disappearance of pulse? However, many times there is VT or VF, why can we start CPR even when there are still slow pulses (escape rhythms or AV blocks in ECG)? Again we are involved in a discussion of terms very hard to define because of the number of pathophysiological concepts and mostly, due to the "dynamics" of events and their sequences. What do experts think?</FONT><FONT class="Apple-style-span" face="Arial"><O:P></O:P></FONT></DIV><DIV class="MsoNormal"><FONT class="Apple-style-span" face="Arial"> </FONT><FONT class="Apple-style-span" face="Arial"><O:P></O:P></FONT></DIV><DIV class="MsoNormal"><FONT class="Apple-style-span" face="Arial">Enrique Asensio L.</FONT><FONT class="Apple-style-span" face="Arial"><O:P></O:P></FONT></DIV><DIV class="MsoNormal"><FONT class="Apple-style-span" face="Arial">México</FONT></DIV><FONT class="Apple-style-span" face="Arial"><BR></FONT><DIV> <SPAN class="Apple-style-span" style="border-collapse: separate; -khtml-border-horizontal-spacing: 0px; -khtml-border-vertical-spacing: 0px; color: rgb(0, 0, 0); font-variant: normal; letter-spacing: normal; line-height: normal; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><DIV><FONT class="Apple-style-span" face="Arial"><BR class="khtml-block-placeholder"></FONT></DIV></SPAN></DIV><DIV><BLOCKQUOTE type="cite"><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><FONT class="Apple-style-span" face="Arial"><BR></FONT></DIV> <DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Arial">Dear colleagues, </FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Arial">I am writing to this list because I would to have some concepts clarified to me regarding the subject of discussion. </FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Arial">I have looked through several articles, books and journals, and they are not clear in this sense. For instance: the Spanish guidelines for CPR mention that there is a very narrow and arbitrary limit between the concepts of cardiorespiratory arrest and sudden cardiac death, leaving one for statistic limits, and the cardiorespiratory arrest as a clinical approach of the problem. </FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Arial">My question for the experts: </FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Arial">Is there some way of defining both concepts, or do they overlap in such a way that they can be used without distinction in related studies and papers?</FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Arial">Other authors point out “reanimation from sudden cardiac death”.</FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Arial">Could it be reanimation from a cardiac arrest? Is it not death precisely that, “death”?</FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 13px/normal Lucida Grande; min-height: 16px; "><FONT class="Apple-style-span" face="Arial" size="3"><SPAN class="Apple-style-span" style="font-size: 12px;"><BR></SPAN></FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Arial">I hope you can clarify this dilemma for me, and thanking you in advance,</FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Arial"><BR class="khtml-block-placeholder"></FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Arial">Dr. Oscar Ruiz Ropero</FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Arial">Intensivista</FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT class="Apple-style-span" face="Arial">Hospital General Docente. Guantanamo. Cuba.</FONT></DIV></BLOCKQUOTE></DIV></BLOCKQUOTE></DIV></BLOCKQUOTE></DIV><BR></BODY></HTML>