Out-of-hospital cardiac arrests Helsinki: Utstein style ... · tively. The cause of cardiac arrest was cardiac in66-5%, andventricularfibrilla-tion was the initial rhythm in 65-0%

Heart 1996;76:18-23

Out-of-hospital cardiac arrests in Helsinki: Utsteinstyle reporting

M Kuisma, T Maatta

AbstractObjective-To determine the epidemiol-ogy of out-of-hospital cardiac arrests andsurvival after resuscitation and to applythe Utstein style of reporting to data col-lection.Design-Prospective cohort study.Setting-A middle-sized urban city (pop-ulation 516 000) served by a single emer-gency medical services system.Patients-Consecutive prehospital car-diac arrests occurring between 1 Januaryand 31 December 1994.Intervention-Advanced cardiac life sup-port according to the recommendations ofAmerican Heart Association.Main outcome measures-Survival fromcardiac arrest to hospital discharge, andfactors associated with survival.Results-Four hundred and twelvepatients were considered for resuscita-tion. The overall incidence of out-of-hospital cardiac arrest was 79-8/100 000inhabitants/year. Fifty seven patients(16.6%) survived to discharge when resus-citation was attempted. 32-5% survivedwhen cardiac arrest was bystander wit-nessed and was ofcardiac origin with ven-tricular fibrillation as the initial rhythm.When asystole or pulseless electricalactivity was the first rhythm recorded,discharge rates were 6-2 and 2-7% respec-tively. The cause of cardiac arrest wascardiac in 66-5%, and ventricular fibrilla-tion was the initial rhythm in 65-0% ofbystander witnessed cardiac arrests ofcardiac origin. 22-1% of patients receivedbystander initiated cardiopulmonaryresuscitation. The mean time intervalsfrom the receipt of the call to the arrivalof a first response advanced life supportunit and mobile intensive care unit at thepatient's side and to the return of sponta-neous circulation were 7-0 and 10-3 and12-6 and 16*7 min respectively. In thelogistic regression model bystander wit-nessed arrest, age, ventricular fibrillationas initial rhythm, and the call-to-arrivalinterval of the first response unit wereindependent factors relating to survival.Utstein style reporting with modificationof time zero was found to be an appropri-ate form of data collection in this emer-gency medical services system.Conclusions-After implementation ofmajor changes in the emergency medicalservices system during the 1980s survivalfrom out-of-hospital cardiac arrest

markedly increased. However, earlyaccess, which has turned out to be theweakest link in the chain of survival,should receive major attention in the nearfuture. Utstein style reporting with amodified time zero was found to beappropriate, although laborious, protocolfor data collection.

(Heart 1996;76:18-23)

Keywords: cardiac arrest; out-of-hospital resuscitation;survival; Utstein style

Utstein recommendations were introduced inthe beginning of 1990s to standardise datareporting on out-of-hospital cardiac arrests.'There had been wide variation in survival ratesdepending on the case and survival definitionselected.2A However, even today there are noepidemiologically comprehensive prospectivestudies in which none of the important sub-groups of the Utstein template (such as car-diac arrests of non-cardiac origin or cardiacarrests in which resuscitation is not attempted)are excluded. The aim of this study was toreport the incidence of out-of-hospital cardiacarrests as well as survival after resuscitation inthe middle-sized urban city of Helsinki and toapply the Utstein style of reporting to data col-lection.

Patients and methodsHELSINKI EMERGENCY MEDICAL SERVICESSYSTEMHelsinki is the capital city of Finland with apopulation of 516 000 and a geographic area of590 kM2. Of the population, 16 6% is youngerthan 16 and 14 0% older than 65 years.

Each year the Helsinki 112 DispatchingCentre dispatches 34 000 urgent medical mis-sions in Helsinki. It is a combined centre formedical, fire, and rescue emergencies. In addi-tion to Helsinki, it serves the province ofUusimaa which increases the population of thedispatching area up to 1 000 000. Dispatch iscriteria based, computer aided, and the dis-patchers are full time employees and havepassed a medical dispatching course. Most dis-patchers give telephone assisted instructionsfor cardiopulmonary resuscitation. The serviceroutinely dispatches assistance during eventinterrogation. The first unit should be dis-patched within one minute and the unit shouldbe mobile within two minutes of the receipt ofthe call.

Helsinki EmergencyMedical ServicesSystem, Departmentof Health, Helsinki,FinlandM KuismaT MidtthCorrespondence to:Dr M Kuisma, HelsinkiEmergency Medical ServicesSystem, Department ofHealth, Agricolankatu 15 A,SF-00530, Helsinki, Finland.Accepted for publication13 February 1996

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Out-of-hospital cardiac arrests in Helsinki: Utstein style reporting

The emergency medical services system isthree tiered and responsible for urgent calls.Both administratively and functionally it isfounded on close cooperation between the res-cue department and the health authority. Non-urgent calls are taken care of by two privateenterprises. The city is divided into eight areaseach of which has an own rescue station. Thefirst tier consists of six ambulances and eightfire engines (used as first response units) staffedwith emergency medical technicians who arecan defibrillate, insert an intravenous line, andintubate adults. The first response unit turnsthe automated electrical defibrillator on whenthey arrive at the patient's side in order to regis-ter the exact time they reach the patient. Theclocks of the defibrillators are synchronisedwith the time in the dispatching centre andchecked daily. Three advanced life supportunits manned with emergency medical techni-cians with training in advanced life supportmake up the second tier, who can administerintravenous drugs. The third tier is the physi-cian staffed mobile intensive care unit.Physicians are also responsible for medicaldirection, education, and development pro-grammes in the emergency medical servicessystem.The calls are classified to four categories; D

is non-urgent, C is urgent and the patient has tobe reached in 20 minutes (neither blue lightsnor siren), and B is urgent with medium orunknown risk (blue lights and siren) andattended by basic and/or advanced life supportunits. For A calls the nearest unit and mobileintensive care unit are dispatched simultane-ously for high risk missions such as severe chestpain, severe trauma, and cardiac arrests.During simultaneous A calls one of theadvanced life support units (medical supervi-sor) is dispatched and the mobile intensive careunit is informed.

Since the previous study in Helsinki in1987,5 there have been major changes in emer-gency medical services system; the introductionof automated electrical defibrillators in 1988,the change from two to three tiered emergencymedical services system in 1989 (until then themobile intensive care unit was the onlyadvanced life support provider), employing fulltime dispatchers from 1990, the use of fireengines as first response units in medical emer-gencies since 1990, and telephone assisted car-diopulmonary resuscitation since 1992.The resuscitation protocol has followed the

guidelines of American Heart Association.6Emergency medical technicians begin resuscita-tion when there are no irreversible signs ofdeath. Do-not-resuscitate decisions are madeby the physician on duty. Excluding hypother-mia cases, patients are completely stabilisedwhere they are found and efforts stopped whenthere is no response to resuscitation attempts.Patients are transported to four receiving hospi-tals; two secondary and one tertiary care facilitiesfor adult patients and one tertiary care facilityfor children.

DATA COLLECTIONThe study plan was approved by the ethics

committee of the City Health Department. Allout-of-hospital cardiac arrest patients withinthe city limits with no irreversible signs ofdeath, were included in the study. Data wereprospectively collected according to a modi-fied Utstein style.' The physician on duty inthe mobile intensive care unit filled in a specialstudy form during each event which waschecked next weekday by the investigator. Forsimultaneous calls the forms were filled in bythe medical supervisor and the mobile inten-sive care unit physician together. The cause ofcardiac arrest was verified from necropsyreports and hospital files by the investigator.The times of the arrival of a first response unit,the arrival of an advanced life support unit,and the arrival of the mobile intensive careunit at the patient's side as well as the time forthe return of spontaneous circulation wereregistered. All data were saved into, a specialcomputer file.

Modification-In this study time zero beganwhen the call was first received whereas in theUtstein recommendations time zero begins atthe time of collapse. We used this modificationbecause the collapse-to-call interval is difficultto define exactly in minutes by an agitatedbystander or when the arrest is not witnessed.

OUTCOME TRACKINGThe end points of the study were death or sur-vival to discharge. Data were obtained fromhospital records by a coordinating physician.The quality of secondary survival at the timeof discharge was measured by a three-tieredclassification:

1 Capable of leading independent life athome.

2 Discharge to rehabilitation centres withmoderate disability with the ultimate purposeof rehabilitation to be able to live at homeindependently.

3 Total disability, not capable of selfcare.Favourable outcome was defined as dis-

charged alive with quality category 1 or 2.

STATISTICAL METHODSStatistical analysis, which concentrated onfinding factors related to survival, was per-formed by a statistician. An exact chi-squaredtest (non-parametric data) and Student's t test(parametric data) were used in univariateanalysis and a logistic regression model wasused for multivariate analysis.

ResultsFour hundred and twelve consecutive patientswere considered for resuscitation. Four hun-dred and eighty four additional patients hadirreversible signs of death on the arrival of thefirst response unit, and were not included inthe study. They were used in the calculation ofthe overall out-of-hospital death rate, how-ever. All patients were followed up until death,discharge home or to a rehabilitation centre,or transfer to a chronic care facility.Calculated from the study population, theincidence of sudden out-of-hospital cardiacarrest was 79 8/100 000 inhabitants/year, the

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Figure 1 Out-of-hospital cardiac arrests (n = 412) reported on the Utstein template.EMS, emergency medical service; VF, ventricularfibrillation; VT, ventriculartachycardia; ROSC, return of spontaneous circulation; ICU, intensive care unit.

corresponding numbers for sudden non-trau-matic cardiac arrest and sudden cardiac arrestof cardiac origin were 73-1 and 53-1/100 000inhabitants/year, respectively. The total num-

19-6

N=255

All Attempted Cardiaccause

22.7

32.5

N=194 N=126

Bystanderwitnessed

VF

40.5

N=42

57-1

N=21

Bystander FirstCPR response

<7 min

Figure 2 Survivalfrom out-of-hospital cardiac arrest in different subgroups. Eachcategory represents a subset of the preceding category. VF, ventricularfibrillation; CPR,cardiopulmonary resuscitation.

ber of deaths from all causes in the communityin 1994 was 982 per 100 000 inhabitants,from which out-of-hospital deaths accountedfor 147 per 100 000 inhabitants (15-0%). Themean (SD) age of the patients was 62-2 years(18.4), range from three months to 94 yearsand 279 (67 8%) were male. Eight patients(1 9%) were under the age of 16 years.

Figure 1 shows the cardiac arrests placed inthe Utstein template and figure 2 shows sur-vival in different subgroups. The overall sur-vival rate in attempted resuscitations was16&6% (57/344). One hundred and twenty sixpatients had a bystander witnessed cardiacarrest of cardiac origin with an initial rhythmof ventricular fibrillation: in 98 of them(77 8%) spontaneous circulation was restored.Eighty (63 5%) were admitted to an intensivecare unit or a hospital ward and 41 (32 5%)were discharged alive. Survival to hospitaladmission and to discharge according to theinitial rhythm is shown in table 1. The totalnumber of survivors from all subgroups was 57(including those with an unwitnessed arrest ora non-cardiac cause): 46 were dischargedhome, four were discharged to a rehabilitationcentre, and seven were discharged to a chroniccare facility with permanent severe disabilitybecause they were not capable of selfcare. Twoof the patients discharged to a chronic carefacility had severe disability before cardiacarrest and there was no change in their statusafter discharge. Thus a favourable outcomewas registered for 50 (87 7%) of the 57 sur-vivors and for 38 of 41 (92 7%) of those inventricular fibrillation.The origin of the cardiac arrest was cardiac

in 274 (66 5%) cases (all template subgroupsincluded). Ventricular fibrillation was the ini-tial rhythm in 65-0% of bystander witnessedcases of cardiac origin. The collapse wasbystander witnessed in 264 (64-1%), unwit-nessed in 97 (23 5%), and witnessed by emer-gency medical service personnel in 51 (12-4%)cases. The dispatching centre recognised 273(75*6%) of 361 cardiac arrests (those wit-nessed by emergency medical service person-nel were excluded). In the remaining 88 casesthe first response unit found a patient in anunexpected cardiac arrest: six had collapsedafter the call. Two hundred and twenty eight(55 3%) patients collapsed at home or in otherprivate premises, 9 (2 2%) at work, 158(38 3%) in public place, 15 (3 6%) in a carefacility, and data were not available in twocases. Ninety one (22 1%) patients receivedbystander initiated cardiopulmonary resuscita-tion. The proportion of bystander initiatedcardiopulmonary resuscitation was highest(33 3%) in the subgroup with bystander wit-nessed ventricular fibrillation of cardiac origin.The mean (SD) time intervals from the

receipt of the call for the first response unit,advanced life support unit, and mobile inten-sive care unit to arrive at the patient's sidewere 7 0 (3 9), 10 3 (6.0), and 12-6 (7 2) min,respectively, and the interval from the receiptof the call to the return of spontaneous circula-tion was 16-7 (7 8) min. Corresponding meanvalues for survivors and non-survivors were

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Table 1 Survival to hospital admission and discharge according to the initial rhythm inthose patients in whom resuscitation was attempted (A) and in those patients in whomresuscitation was attempted after a cardiac arrest of cardiac origin witnessed by abystander (B)

Initial rhythm

Ventricular Ventricular Pulseless electricalfibrillation tachycardia Asystole activity

A:All (n = 344) 155 2 113 74Admitted to ICU or ward 97 (626%) 1 (50%) 34 (30-1%) 19 (27-5%)Discharged 47 (30 3%) 1 (50%) 7 (6 2%) 2 (2 7%)

B:All (n= 194) 126 1 41 26Admitted to ICU or ward 80 (63 5%) 1 (100%) 10 (24-4%) 7 (26 9%)Discharged 41 (32 5%) 1 (100%) 1 (2 4%) 1 (3-8%)

ICU, intensive care unit.

6 0/8 0 (P = 0-0001), 9d1/11-4 (P = 0-0014),and 11 5/14-0 min (P = 0-0189), respectively.

In univariate analysis, factors related to sur-vival were bystander witnessed arrest (P =0-001), ventricular fibrillation as initial rhythm(P < 0-001), bystander initiated cardiopul-monary resuscitation (P = 0 002), and timeintervals as shown in the previous paragraph.In multivariate analysis (logistic regressionmodel) age (OR 1-03, 95% CI 1 01 to 1P06),bystander witnessed arrest (OR 8-57, 95% CI1-84 to 40 07), ventricular fibrillation as initialrhythm (OR 4 43, 95% CI 1P60 to 12-28), andthe call-to-arrival interval of the first responseunit (OR 1P25, 95% CI 1P06 to 1P46) wereindependent factors related to survival. Table2 gives specific data on patients with bystanderwitnessed arrest of cardiac origin with ventric-ular fibrillation as the initial rhythm.The physician on duty decided not to

attempt resuscitation in 68 (16-5%) patients.The causes of the do-not-resuscitate decisionwere injury in 30, long collapse-to-arrivalinterval for the first reponse unit in 19, incur-able illness such as metastatic cancer or severedementia in 10, living will in two, and a com-bination of at least two of the above causes infour cases. Data were not available in threecases.

Table 2 Comparison of survival and resuscitation data in 126 cardiac arrest patients inwhom resuscitation was attempted: the arrest was bystander witnessed, ofcardiac origin,and the first recorded rhythm was ventricularfibrillation

Survived Died P

Sex:Male 34 61Female 7 23 0-205

Age (y) (mean (SD)) 62-0 (12-6) 68-9 (14-8) 0-012Bystander cardiopulmonaryresuscitation:

Yes 17 25No 24 60 0-179

Scene of collapse:Home 11 43Work 2 2Public place 27 38Care facility 1 2 0-086

Recognition of cardiac arrestby the dispatching centre:

Yes 11 25No 30 60 0-764

Time-intervals (min) (mean (SD)):To first responding unit 5-7 (2 3) 7-4 (2-6) 0-001To ALS unit 9-3 (4-5) 10-6 (6 4) 0-187ToMICU 11-7(62) 137(78) 0-173To ROSC 14-7 (6 5) 18 4 (7-8) 0-016

Venous cannulation:External jugular 24 48Antecubital 17 37 0-723

ALS, advanced life support; MICU, mobile intensive care unit; ROSC, return of spontaneous cir-culation. Time intervals for units are calculated from the time the call was first received to thearrival at the patient's side.

DiscussionSurvival from out-of-hospital cardiac arrest(16-6% in attempted resuscitation and 32-5%in bystander witnessed ventricular fibrillationof cardiac origin) is comparable to reportsfrom the suburban United States (KingCounty) (16 and 34% respectively).2 How-ever, the response times of the first responseunits are longer and cardiopulmonary resusci-tation performed by citizens is relatively rare inHelsinki compared with King County.Current knowledge indicates that middle-sizedurban emergency medical services systems(population approximately 500 000) are opti-mal for survival from out-of-hospital cardiacarrest. Survival rates have been reported to belower both in rural and small city emergencymedical services systems7 8 and in large cities.910Very large emergency medical services systemsare more difficult to coordinate and supervise,it may take too long to arrive at the patient'sside. Also sociodemographic features typical oflarge cities (poverty, poor baseline health) maycontribute to low survival rates.'0

Becker et al reviewed 20 publications whichincluded information about the incidence ofout-of-hospital cardiac arrest." Incidence ratesvaried markedly, from 35 to 128 per 100 000,with a mean of 62. The knowledge of case def-inition, the availability of necropsy reports andthe comprehensiveness of the emergency med-ical services are relevant when interpretingincidence rates. Cardiac causes are likely to beoverestimated if the cause of cardiac arrest isascertained purely on the basis of the clinicalsituation and preexisting history.5 Weexpressed our results as three incidence rates(overall 79-8, non-traumatic 73-1, and cardiac53-1/100 000) to make the comparison morereliable.

Compared with the previous report fromHelsinki in 19875 the overall incidence of sud-den out-of-hospital cardiac arrest haddecreased from 112-6 to 79-8/100 000 withouta major change in the incidence of ventricularfibrillation. Survival from ventricular fibrilla-tion (defined as witnessed arrest with pre-sumed heart disease including arrestswitnessed by emergency medical personnel in19875 and bystander witnessed arrest of car-diac origin in the present study) has increasedfrom 27 to 32-5%. The introduction of auto-mated electrical defibrillators is thought tohave had a major impact on the increased sur-vival rate.'2 The results of the previous study5and the present one are not altogether compa-rable because between studies the Utstein styledata collection system was introduced inHelsinki. Because of the different calculationprinciples (the receipt of the call v dispatching,and arrival at the patient's side v arrival at thescene) time intervals cannot be compareddirectly, but it seems that the crucial intervalsare at least as long as in 1987.5 The results ofthe multivariate analysis are comparable withprevious studies from different emergencymedical services, although the factor ofbystander initiated cardiopulmonary resuscita-tion did not reach the level of statistical signifi-cance in this study.9 13

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The chance of survival is low if the initialrhythm recorded is asystole or pulseless elec-trical activity. In a series of 1222 patients fromGothenburg treated by the emergency medicalservices with asystole as the initial rhythm, 7%of the patients were admitted to hospital and2% were discharged.'4 The corresponding fig-ures were 13% and 2% when electromechani-cal dissociation was the initial rhythm in 748cases.'5 In another recent study discharge ratesfor patients initially found in asystole andelectromechanical dissociation were 1 6% and6&9%, but most cardiac arrests with a non-car-diac cause had been excluded.16 The 6&2%overall survival rate in cases of asystole in thisstudy is higher than previously reported,'416but the rate is reduced to 2-5% in cases of wit-nessed arrests of cardiac origin. The differencemay be explained by the contribution of car-diac arrests of non-cardiac origin known to beassociated with better prognosis (near-drown-ing17 or airway obstruction). Although the sur-vival rates remain low in cases of asystole and incases of pulseless electrical activity, such casescan make up more than one fifth of the totalsurvivorship, which makes resuscitation effortsin such cases worthwhile.16

Bystander initiated cardiopulmonary resus-citation improves survival from out-of-hospitalcardiac arrest by maintaining minimal vitalorgan perfusion until spontaneous circulationis restored and perhaps most importantly bymaintaining the heart in ventricular fibrillationand making it easier to convert by defibrilla-tor.1318 These findings are also supported bythis study where the frequency of bystandercardiopulmonary resuscitation was highest inthe ventricular fibrillation group, but the rela-tion to survival remained statistically non-significant. However, the overall 22 1%bystander cardiopulmonary resuscitation ratein Helsinki is alarmingly low for a developedemergency medical services system and com-pared with the situation in-for example, NewYork. 10 The reason for the low rate may be thelack of adequate education rather than thereluctance of people to initiate cardiopul-monary resuscitation.

In one quarter of cases a cardiac arrestremained unrecognised by the dispatchingcentre, the corresponding figure in 1987-88was 47%.19 A cardiac arrest can be recognisedover the telephone if the caller can answerthree simple questions: What has happened? Isthe patient awake/can she be woken up? Is shebreathing normally? In most cases thatremained unrecognised the caller did notknow what had happened: he had merely beenasked to call an ambulance quickly. In theremaining cases the dispatching protocol wasnot obeyed. Public education on making anemergency call and continuing education andsupport of the dispatchers are needed to raisethe cardiac arrest recognition rate. It is obvi-ous that dispatching should receive moreattention in data collection in the future.

Utstein style reporting was found to be suit-able for prospective data collection in thisemergency medical services system. We choseto record the time when the call was first

received as time zero, contrary to the Utsteinrecommendation. It is possible to record theinterval between the call receipt and arrival atthe scene or preferably at the patient's side inseconds and that is why it should be separatedfrom the less exact collapse-to-call interval.The weakest part in the chain of survival in

Helsinki emergency medical services systemseems to be early access and early bystandercardiopulmonary resuscitation. Collapse-to-call intervals are too long and bystander ini-tiated cardiopulmonary resuscitation uncom-mon. Educational programmes for citizensshould include how to recognise an emer-gency, how to make a correct emergency callso that the dispatching centre can make a riskevaluation and use scarce resources reason-ably, and when and how to start citizen car-diopulmonary resuscitation.

CONCLUSIONSSince late 1980s after major changes in emer-gency medical services system were imple-mented, survival from out-of-hospital cardiacarrest has markedly increased. However, earlyaccess, the weakest link in the chain of survivalneeds major attention and development in thenear future. Utstein style reporting with amodified time zero was found to be an appro-priate, although laborious, approach to datacollection.

We thank Dr Per Rosenberg for valuable comments, AnneliOjajari, for statistical review, Matti Nieminen, ADP designer,for help in developing the computer based data collection sys-tem, Leena-Marja Kokko, for assistance in data processing andthe Laerdal Foundation for financial support.

1 Cummins RO, Chamberlain DA, Abramson NS, Allen M,Baskett P, Becker L, et al. Recommended guidelines foruniform reporting of data from out-of-hospital cardiacarrest: the Utstein style. Ann Emerg Med 1991;20:861-74.

2 Eisenberg MS, Cummins RO, Larsen MP. Numerators,denominators, and survival rates: reporting data fromout-of-hospital cardiac arrest. Am J Emerg Med 1991;9:544-6.

3 Valenzuela TD, Spaite DW, Meislin HV, Clark LL, EwyGA. Case and survival definitions in out-of-hospital car-diac arrest: effect on survival rate calculation. JAMA1992;267:272-4.

4 Joslyn SA. Case definition in survival studies of out-of-hos-pital cardiac arrest. Am J Emerg Med 1994;12:299-301.

5 Silfvast T. Prehospital resuscitation in Helsinki, Finland.Am J EmergMed 1990;8:359-64.

6 American Heart Association. Guidelines for cardiopul-monary resuscitation and emergency cardiac care.Recommendations of the 1992 national conference.JAMA 1992;268:2251-75.

7 Stults KR, Brown DD, Schug VL, Bean JA. Prehospitaldefibrillation performed by emergency medical techni-cians in rural communities. N Engl J Med 1984;310:219-23.

8 Bachman JW, McDonald GS, O'Brien PC. A study of out-of-hospital cardiac arrests in Northeastern Minnesota.JAAMA 1986;256:477-83.

9 Becker LB, Ostrander MP, Barrett J, Gondos GT.Outcome ofCPR in a large metropolitan area-where arethe survivors. Ann Emerg Med 199 1;20:355-61.

10 Lombardi G, Gallagher J, Gennis P. Outcome of out-of-hospital cardiac arrest in New York City. The pre-hospitalarrest survival evaluation (PHASE) study. JAAMA 1994;271:678-83.

11 Becker LB, Smith DV, Rhodes KV. Incidence of cardiacarrest: a neglected factor in evaluating survival rates. AnnEmerg Med 1993;22:86-9 1.

12 Weaver WD, Hill D, Fahrenbruch CE. Use of the auto-matic external defibrillator in the management of out-of-hospital cardiac arrest. NEnglJ Med 1988;319:661-6.

13 Herlitz J, Ekstrom L, Wennerblom B, Axelsson A, Bang A,Holmberg S. Effect of bystander initiated cardiopul-monary resuscitation on ventricular fibrillation and sur-vival after witnessed cardiac arrest outside hospital. BrHeartrJ 1994;72:408-12.

14 Herlitz J, Ekstrom L, Wennerblom B, Axelsson A, Bang A,Holmberg S. Predictors of early and late survival afterout-of-hospital cardiac arrest in which asystole was thefirst recorded arrhythmia on scene. Resuscitation 1994;28:27-36.

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15 Herlitz J, Ekstrom L, Wennerblom B, Axeisson A, Bang A,Holmberg S. Survival among patients with out-of-hospitalcardiac arrest found in electromechanical dissociation.Resuscitation 1995;29:97-106.

16 Pepe PE, Levine RL, Fromm RE, Curka PA, Clark PS,Zachariah BS. Cardiac arrest presenting with rhythmsother than ventricular fibrillation: contribution of resusci-tative efforts toward total survivorship. Crit Care Med1993;21:1838-43.

17 Kuisma M, Suominen P, Korpela R. Paediatric out-of-hos-

pital cardiac arrests-epidemiology and outcome.Resuscitation 1995;30: 141-50.

18 Swor RA, Jacson RE, Cynar M, Sadler E, Basse E, Boji B, etal. Bystander CPR, ventricular fibrillation, and survivalin witnessed, unmonitored out-of-hospital cardiac arrest.Ann Emerg Med 1995;25:780-4.

19 Silfvast T. Prehospital resuscitation in Helsinki. Experiencewith a physician staffed emergency care unit in1987-1988. Helsinki: University of Helsinki, 1990:28pp. Dissertation.

IMAGES IN CARDIOLOGY

Earthquake tachycardia in Belgium

A 52 year old woman complained of recurrentpalpitation. Clinical examination, electrocar-diogram, echocardiogram, and exercise test-ing were entirely normal. Holter monitoringshowed a normal sinus rhythm (average 69beats per minute) at night, until on 20 June1995 she was woken suddenly at 4 05 am byan earthquake (4 4 on the Richter scale). Theearthquake was followed by sinus tachycardia(recognised by the patient as her usualarrhythmia) of up to 150 beats per minute.The figure shows (A) the electrocardio-

graphic tracing and (B) the heart rate trend.The standard deviation of the normal RRintervals measured in the 15 minutes immedi-ately before she was woken was 42 ms. Heartrate (HR) variability was further analysed withpower (P) spectral analysis using fast Fouriertransformation (FFT). This quantifies thehigh frequency (HF) and low frequency (LF)

A ~~~~~~~~~~~~~~~~ -. -A -

II .I I' I' I

~~~~~~~~U U

components of the total (T) power spectrum.Her sudden awakening probably inducedsympathetic activation with disappearance ofvagal tone. This is reflected by the change inthe LF/HF balance, caused by the loss of theHF component-(C) before waking (D) afterwaking.

These findings confirm how external fac-tors (and others such as pain and emotion)can induce sudden and strong adrenergicstimulation. In Los Angeles and Kobe earth-quakes were associated with an increase in thecardiac event rate.'

MICHEL DE PAUWRENE TAVERNIERLUC JORDAENS

Department of Cardiovascular DiseasesUniversity Hospital Ghent,

Ghent, Belgium

1 Leor J, Kloner RA. Scared to death? The occurrence ofsudden cardiac death during the 1994 NorthridgeEarthquake (abstract). Circulation 1995;92 suppl:I 96.

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Out-of-hospital cardiac arrests Helsinki: Utstein style ... · tively. The cause of cardiac arrest was cardiac in66-5%, andventricularfibrilla-tion was the initial rhythm in 65-0%