WordNet

absence of systole; failure of the ventricles of the heart to contract (usually caused by ventricular fibrillation) with consequent absence of the heart beat leading to oxygen lack and eventually to death (同)cardiac_arrest, cardiopulmonary_arrest
a premature systole resulting in a momentary cardiac arrhythmia

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/01/12 11:30:35」(JST)

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In medicine, asystole /əˈsɪstəliː/, colloquially known as flatline, is a state of no cardiac electrical activity, hence no contractions of the myocardium and no cardiac output or blood flow. Asystole is one of the conditions that may be used for a medical practitioner to certify clinical or legal death.

Asystole is treated by cardiopulmonary resuscitation (CPR) combined with an intravenous vasopressor such as epinephrine (aka adrenaline). Sometimes an underlying reversible cause can be detected and treated (the so-called 'Hs and Ts', an example of which is hypokalaemia). Several interventions previously recommended—such as defibrillation (known to be ineffective on asystole, but previously performed in case the rhythm was actually very fine ventricular fibrillation) and intravenous atropine—are no longer part of the routine protocols recommended by most major international bodies.^[1] Asystole may be treated with 1 mg epinephrine by IV every 3–5 minutes as needed. Vasopressin 40 units by IV every 3–5 minutes may be used in place of the first and/or second doses of epinephrine, but doing so does not enhance outcomes.

Survival rates in a cardiac arrest patient with asystole are much lower than a patient with a rhythm amenable to defibrillation; asystole is itself not a "shockable" rhythm. Out-of-hospital survival rates (even with emergency intervention) are less than 2 percent.^[2]

Cause

Possible underlying causes include the Hs and Ts.^[3]^[4]^[5]

Hypovolemia
Hypoxia
Hydrogen ions (acidosis)
Hypothermia
Hyperkalemia or Hypokalemia
Hypoglycemia
Tablets or Toxins (drug overdose)
Tachycardia
Cardiac Tamponade
Tension pneumothorax
Thrombosis (myocardial infarction or pulmonary embolism)
Trauma (hypovolemia from blood loss)

While the heart is asystolic, there is no blood flow to the brain unless CPR or internal cardiac massage (when the chest is opened and the heart is manually compressed) is performed, and even then it is a small amount. After many emergency treatments have been applied but the heart is still unresponsive, it is time to consider pronouncing the patient dead. Even in the rare case that a rhythm reappears, if asystole has persisted for fifteen minutes or more, the brain will have been deprived of oxygen long enough to cause brain death.

ECG lead showing asystole (flatline)

References

^ AHA Cardiac Recussitation Guidelines, 2010: http://circ.ahajournals.org/cgi/content/full/122/18_suppl_3/S729
^ http://journals.lww.com/surveyanesthesiology/Citation/2008/10000/Medical_Futility_in_Asystolic_Out_of_Hospital.44.aspx
^ Mazur G (2004). ACLS: Principles And Practice. Dallas: American Heart Assn. pp. 71–87. ISBN 0-87493-341-2.
^ Barnes TG, Cummins RO, Field J, Hazinski MF (2003). ACLS for experienced providers. Dallas: American Heart Assn. pp. 3–5. ISBN 0-87493-424-9.
^ ECC Committee, Subcommittees and Task Forces of the American Heart Association (Dec 2005). "2005 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care - Part 7.2: Management of Cardiac Arrest.". Circulation 112 (24 Suppl): IV1–203 (7.2 IV58–66). doi:10.1161/CIRCULATIONAHA.105.166550. PMID 16314375.

UpToDate Contents

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English Journal

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Japanese Journal

Impact of Therapeutic Hypothermia in the Treatment of Patients With Out-of-Hospital Cardiac Arrest From the J-PULSE-HYPO Study Registry

YOKOYAMA Hiroyuki,NAGAO Ken,HASE Mamoru,TAHARA Yoshio,HAZUI Hiroshi,ARIMOTO Hideki,KASHIWASE Kazunori,SAWANO Hirotaka,YASUGA Yuji,KURODA Yasuhiro,KASAOKA Shunji,SHIRAI Shinichi,YONEMOTO Naohiro,NONOGI Hiroshi
Circulation journal : official journal of the Japanese Circulation Society 75(5), 1063-1070, 2011-04-25
… Initial electrocardiogram rhythm at the time of occurrence of the cardiac arrest showed 68.9% had ventricular fibrillation or pulseless ventricular tachycardia, 13.7% had pulseless electrical activity, and 9.1% had asystole. …
NAID 10028147262

Report From the Japanese Registry of CPR for In-Hospital Cardiac Arrest (J-RCPR)

YOKOYAMA Hiroyuki,YONEMOTO Naohiro,YONEZAWA Kazuya,FUSE Jun,SHIMIZU Naoki,HAYASHI Toshimasa,TSUJI Teppei,YOSHIKAWA Kei,WAKAMATSU Hiroya,OTANI Nozomu,SAKURAGI Satoru,FUKUSAKI Masahiko,TANAKA Hideki,NONOGI Hiroshi
Circulation journal : official journal of the Japanese Circulation Society 75(4), 815-822, 2011-03-25
… The prevalence of pulseless VT/VF as first documented rhythm was 28.1%, asystole was 29.5% and pulseless electrical activity was 41.1%. …
NAID 10028103021

Atropine Sulfate for Patients With Out-of-Hospital Cardiac Arrest due to Asystole and Pulseless Electrical Activity

YAGI Tsukasa,NAGAO Ken
Circulation journal : official journal of the Japanese Circulation Society 75(3), 580-588, 2011-02-25
… In the 6,419 adults with asystole, the epinephrine with atropine group (n=1,378) had a significantly higher return of spontaneous circulation (ROSC) rate than the epinephrine alone group (n=5,048) with an adjusted odds ratio of 1.6 (95% confidence interval (CI) 1.4-1.7, P<0.0001), but the 2 groups had similar 30-day favorable neurological outcome with an adjusted odds ratio of 0.6 (95%CI 0.2-1.7; …
NAID 10028101887

Related Pictures

★リンクテーブル★

リンク元	「心停止」「無脈性電気活動」「心静止」「heart arrest」「asystolic」

「心停止」

Asystole
	A rhythm strip showing two beats of normal sinus rhythm followed by an atrial beat and asystole.
Classification and external resources
Specialty	cardiology
ICD-10	I46.0
ICD-9-CM	427.5