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Long-term follow-up of sudden cardiac arrest survivors and electrophysiologically guided antiarrhythmic therapy.

Sudden cardiac arrest survivors have a high risk of suffering from recurrent arrhythmic events. Recent studies have shown that these patients have a significantly decreased mortality rate, if they are supplied with an implantable cardioverter/defibrillator (ICD). The aim of this study was to evaluate the long-term prognosis of patients with electrophysiologically guided antiarrhythmic drug therapy in comparison to patients with ICD. 204 consecutive survivors of sudden cardiac arrest were enrolled in this study. All patients were examined with an initial electrophysiologic study (EPS) with programmed ventricular stimulation. Patients were treated with antiarrhythmic drugs (if the inducible tachycardia was suppressed) or with the implantation of an ICD. The maximal follow-up period was 120 months, the mean period was 53.3 +/- 31.4 months (ICD) versus 60.3 +/- 35.5 months (EPS, nonsignificant). Patients with ICD showed an overall mortality rate of 14.6%, whereas EPS-guided patients had a mortality rate of 43.2% (p < 0.001). The cardiac and arrhythmogenic mortality rates were significantly lower in the ICD group (12 vs. 43%, p < 0.01, and 1 vs. 16%, p < 0.001, respectively). A reduction of the mortality risk was observed in the ICD group by up to 61% (all-cause mortality), 52% (cardiac mortality) and 97.2% (arrhythmogenic mortality). In arrhythmic event survivors with ICD, arrhythmic and overall mortality rates are significantly lower compared to patients with an EPS-guided drug therapy. In the secondary prevention of sudden cardiac death, ICD should be the first choice of antiarrhythmic therapy.

Adult↗

Procalcitonin serum levels after out-of-hospital cardiac arrest.

The time course of Procalcitonin (PCT) serum levels was assessed in cardiac arrest survivors and compared with S-100 serum levels concerning their predictive values for neurological outcome. PCT and S-100 serum levels were analyzed serially on admission and during the following 3 days after hospitalization in 23 patients successfully resuscitated from out-of-hospital cardiac arrest. At day 14 patients were divided into groups according to the Glasgow-Outcome-Scale (GOS): one group with bad neurological outcome (GOS 1-3) and one group with good neurological outcome (GOS 4-5). Group comparisons were performed with the Mann-Whitney U-Test. The diagnostic performance of PCT and S-100 levels was analyzed using receiver operating characteristics (ROC). Patients with a bad neurological outcome had significantly higher S-100 levels than those with a good neurological outcome at all investigated time points and significantly elevated PCT levels at days 1-3. Highest levels for S-100 were found immediately after hospitalization (3.4 +/- 3.8 vs. 0.7 +/- 0.3 microg/l, P=0.003), and for PCT at day 1 (37 +/- 103 vs. 0.2 +/- 0.2 microg/l, P=0.0002). The results show that PCT serum levels are possibly elevated in patients with bad neurological outcome after cardiac arrest, without signs of severe infection or concomitant sepsis. Based on this observation, studies on larger numbers of patients should prove the predictive value of PCT in those patients.

After-Hours Care↗

The management of cardiac arrest in infants and children.

The management of cardiac arrest in adults is a well known and, in most hospitals, a well practised procedure. Similarly the resuscitation of the newborn is usually well provided for. However, cardiac arrests occurring in older children can cause difficulties.

Acidosis↗

In-hospital cardiac arrest: incidence, prognosis and possible measures to improve survival.

DESIGN: Review. OBJECTIVE: Medical literature on in-hospital cardiac arrest (IHCA) was reviewed to summarise: (a) the incidence of and survival after IHCA, (b) major prognostic factors, (c) possible interventions to improve survival. RESULTS AND CONCLUSIONS: The incidence of IHCA is rarely reported in the literature. Values range between 1 and 5 events per 1,000 hospital admissions, or 0.175 events/bed annually. Reported survival to hospital discharge varies from 0% to 42%, the most common range being between 15% and 20%. Pre-arrest prognostic factors: the prognostic value of age is controversial. Among comorbidities, sepsis, cancer, renal failure and homebound lifestyle are significantly associated with poor survival. However, pre-arrest morbidity scores have not yet been prospectively validated as instruments to predict failure to survive after IHCA. Intra-arrest factors: ventricular fibrillation/ventricular tachycardia (VF/VT) as the first recorded rhythm and a shorter interval between IHCA and cardiopulmonary resuscitation or defibrillation are associated with higher survival. However, VF/VT is present in only 25-35% of IHCAs. Short-term survival is also higher in patients resuscitated with chest compression rates above 80/min. Interventions likely to improve survival include: early recognition and stabilisation of patients at risk of IHCA to enable prevention, faster and better in-hospital resuscitation and early defibrillation. Mild therapeutic hypothermia is effective as post-arrest treatment of out-of-hospital cardiac arrest due to VF/VT, but its benefit after IHCA and after cardiac arrest with non-VF/VT rhythms has not been clearly demonstrated.

Age Factors↗

Unexpected cardiac arrest in patients after surgical correction of tetralogy of Fallot.

Four of 220 patients without bifasicular block (complete right bundle branch block and left anterior hemiblock) or transient complete heart block immediately after surgery had an unexpected cardiac arrest one to 15 years after satisfactory surgical repair of tetralogy of Fallot. The postoperative electrocardiograms (ECG) revealed complete right bundle branch block in two patients and no intraventricle conduction abnormality in two patients. Each of the four patients had premature ventricular contractions on previous postoperative ECG. The cardiac arrest occurred during normal activity in three patients and mild exercise in one. Following the cardiac arrest, three patients died and one patient survived. Eighteen months before the cardiac arrest, the survivor had a stress test which revealed multifocal premature ventricular contractions with short bursts of ventricular tachycardia after exercise. This ventricular arrhythmia was suppressed with quinidine therapy. Although complete heart block cannot be excluded in these four patients, we reasoned that the cardiac arrests were probably preceded by ventricular tachyarrhythmia. Because of this experience, we believe that any patient who has had intraventricular surgery should be evaluated for ventricular arrhythmia. If frequent premature ventricular contractions or serious ventricular arrhythmias are documented, we seriously consider antiarrhythmic therapy in an attempt to prevent ventricular tachyarrhythmias and sudden death.

Adolescent↗

Diuretic therapy for hypertension and the risk of primary cardiac arrest.

BACKGROUND: The results of trials of the primary prevention of coronary heart disease have suggested that treating hypertension with high doses of thiazide diuretic drugs might increase the risk of sudden death from cardiac causes. In contrast, treatment with low doses of thiazide reduces the risk of coronary heart disease. METHODS: To examine the association between thiazide treatment for hypertension and the occurrence of primary cardiac arrest, we conducted a population-based case-control study among enrollees of a health maintenance organization. The case patients were 114 persons with hypertension who had a primary cardiac arrest from 1977 through 1990. The control patients were a stratified random sample of 535 persons with hypertension. The patients' treatment was assessed with the use of a computerized pharmacy data base. Records of their ambulatory care were reviewed to determine other clinical characteristics. RESULTS: The risk of primary cardiac arrest among patients receiving combined thiazide and potassium-sparing diuretic therapy was lower than that among patients treated with a thiazide without potassium-sparing therapy (odds ratio, 0.3; 95 percent confidence interval, 0.1 to 0.7). As compared with low-dose thiazide therapy (25 mg daily), moderate-dose therapy (50 mg daily) was associated with a moderate increase in risk (odds ratio, 1.7; 95 percent confidence interval, 0.7 to 4.5), and high-dose therapy (100 mg daily) was associated with a larger increase in risk (odds ratio, 3.6; 95 percent confidence interval, 1.2 to 10.8) (P value for trend, 0.02). The addition of a potassium-sparing drug to low-dose thiazide therapy was associated with a reduced risk of cardiac arrest (odds ratio, 0.4; 95 percent confidence interval, 0.1 to 1.5). CONCLUSIONS: Both the dose of thiazide drugs and the addition of potassium-sparing drugs influence the risk of primary cardiac arrest. These results may explain the differences in the effect of antihypertensive therapy on mortality from coronary heart disease in previous clinical trials.

Aged↗

Vasopressin improves vital organ blood flow after prolonged cardiac arrest with postcountershock pulseless electrical activity in pigs.

OBJECTIVE: Although a benefit of vasopressin when compared with epinephrine was shown during cardiopulmonary resuscitation (CPR) after a short duration of ventricular fibrillation cardiac arrest, the effect of vasopressin during prolonged cardiac arrest with pulseless electrical activity is currently unknown. DESIGN: Prospective, randomized laboratory investigation using an established porcine model with instrumentation for measurement of hemodynamic variables, vital organ blood flow, blood gases, and return of spontaneous circulation. SETTING: University hospital laboratory. SUBJECTS: Eighteen domestic pigs. INTERVENTIONS: After 15 mins of cardiac arrest and 3 mins of chest compressions, 18 animals were randomly treated with either 0.8 units/kg vasopressin (n = 9) or 200 microg/kg epinephrine (n = 9). MEASUREMENTS AND MAIN RESULTS: Compared with epinephrine, vasopressin resulted, at both 90 secs and 5 mins after drug administration, in significantly higher (p < .05) median (25th-75th percentiles) left ventricular myocardial blood flow (120 [range, 96-193] vs. 54 [range, 11-92] and 56 [range, 41-80] vs. 21 [range, 11-40] mL/min/100 g, respectively) and total cerebral blood flow (85 [78-102] vs. 24 [18-41] and 50 [44-52] vs. 8 [5-23] mL/min/100 g, respectively). Spontaneous circulation was restored in eight of nine animals in the vasopressin group and in one of nine animals in the epinephrine group (p = .003). CONCLUSIONS: Compared with a maximum dose of epinephrine, vasopressin significantly increased left ventricular myocardial and total cerebral blood flow during CPR and return of spontaneous circulation in a porcine model of prolonged cardiac arrest with postcountershock pulseless electrical activity.

Animals↗

Out-of-hospital cardiac arrest in patients with no overt heart disease: electrophysiologic observations and clinical outcome.

Electrophysiologic studies were performed in nine survivors of out-of-hospital cardiac arrest who had no overt heart disease on clinical, hemodynamic and angiographic evaluation. Cardiac arrest occurred during sedentary activity in seven patients and during exercise in two; no patient was on antiarrhythmic drugs at the time of cardiac arrest. Twenty-four hour ambulatory electrocardiographic monitoring demonstrated premature ventricular beats in four patients (44%). Electrophysiologic stimulation induced sustained ventricular tachycardia (VT) or fibrillation (VF) in five patients, nonsustained VT in one patient and less than five ventricular beats in the remaining three patients. Of five patients with inducible sustained VT or VF, four had complete suppression of inducible VT with antiarrhythmic therapy, and none of these four patients died suddenly or had clinical VT after an average follow-up of 27 months (range 12 to 41 months). The remaining patient with inducible sustained VT refused serial electropharmacologic testing, was treated empirically with amiodarone (400 mg/day) and died suddenly eight months later. Of the four patients with noninducible sustained VT or VF, three received no antiarrhythmic therapy and one was given a beta-blocker. None had recurrent cardiac arrest or symptomatic VT after an average follow-up of 17 months (range 13 to 20 months). Thus, inducibility of sustained VT or VF provided a reliable end point for long term antiarrhythmic therapy and noninducibility identified a subset of patients that had an excellent prognosis without specific antiarrhythmic therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Continuation of CPR on admission to emergency department after out-of-hospital cardiac arrest. Occurrence, characteristics and outcome.

AIM: To describe the occurrence, characteristics and outcome among patients with out-of-hospital cardiac arrest who required continuation of cardiopulmonary resuscitation (CPR) on admission to the emergency department. PATIENTS: all patients in the municipality of Göteborg who suffered out-of-hospital cardiac arrest, were reached by the emergency medical service (EMS) system and in whom CPR was initiated. Period for inclusion in study: 1 Oct. 1980-31 Dec. 1992. RESULTS: of 334 out-of-hospital cardiac arrests, 2,319 (68%) were receiving on-going CPR at the time of admission to hospital. Of these, 137 patients (6%) were hospitalized alive and 28 (1.2%) could be discharged from hospital. Of these patients, 39% had a cerebral performance categories (CPC) score of 1 (no cerebral deficiency), 18% had a CPC score of 2 (moderate cerebral deficiency), 36% had a CPC score of 3 (severe cerebral deficiency) and 7% had a CPC score of 4 (coma) at discharge. Among patients discharged. 76% were alive after 1 year. CONCLUSION: among consecutive patients with out-of-hospital cardiac arrest, CPR was ongoing in 68% of them on admission to hospital. Among these patients, 6% were hospitalized alive and 1.2% were discharged from hospital. Thus, among patients with ongoing CPR on admission to hospital, survivors can be found but they are few in numbers and extensive cerebral damage is frequently present.

Adolescent↗

Plasma catecholamines in patients with acute myocardial infarction and in cardiac arrest.

Plasma catecholamine concentrations in cardiac arrest (ventricular fibrillation and asystole) are significantly higher than after myocardial infarction. The levels reached are well above those normally required to stimulate cardiac activity. Possible reasons for the failure of the myocardium to respond to the catecholamines are discussed and the rationale for giving more catecholamines is questioned.

Adult↗

Effects of endothelin-1 on resuscitation rate during cardiac arrest.

OBJECTIVES: Endothelin-1 (ET-1) is a potent peripheral and coronary artery vasoconstrictor and has been shown to improve coronary perfusion pressure (CPP) during cardiac arrest. The effect of ET-1 on return of spontaneous circulation (ROSC) following cardiac arrest has not been studied. Our hypothesis was that ET-1 does not improve ROSC from cardiac arrest when compared to placebo. METHODS: A total of 11 immature swine were used in this laboratory study. Animals were randomized to receive 300 microg ET-1 and standard dose epinephrine (SDE) or placebo and SDE during arrest. After a 10-min period of no-flow ventricular fibrillation (VF), CPR was performed for 3 min followed by ET-1/SDE or placebo/SDE administration. Following drug administration, standard ACLS was followed with SDE given every 3 min. Aortic pressure was monitored during resuscitation. ROSC was defined as any perfusing rhythm with a systolic pressure greater than 60 mmHg for 60 s. Animals received post-ROSC care as needed for 2 h post-ROSC. CPP and ROSC were analyzed using repeated measures ANOVA and Fischer's exact test respectively. P<0.05 was considered significant. RESULTS: Pre-arrest variables and CPP prior to ET-1 administration were not different between groups. Following ET-1 administration, CPP was significantly increased at all time points in ET-1/SDE versus placebo/SDE animals. ROSC was achieved in 1/5 (20%) ET-1/SDE versus 1/6 (16.7%) placebo/SDE animals (P>0.05). The resuscitated ET-1/SDE animal survived 6.5 min compared to 120 min for the resuscitated placebo/SDE animal. CONCLUSIONS: In our study, ET-1 administration during cardiac arrest increases CPP but does not improve ROSC.

Animals↗

Aminophylline as an adjunct to standard advanced cardiac life support in prolonged cardiac arrest.

STUDY HYPOTHESIS: We hypothesized that the addition of aminophylline to Advanced Cardiac Life Support (ACLS) interventions would improve the initial resuscitation success rate in an animal model of prolonged cardiac arrest. METHODS: We used a double-blind, placebo-controlled, randomized-block design with a follow-up open-label uncontrolled phase. We studied 24 female domestic mixed-breed swine (body mass, 20 to 25 kg). After electrical induction of ventricular fibrillation, animals were subjected to 8 minutes of no-flow cardiac arrest followed by 1 minute of mechanical ventilation and closed-chest compressions. Nine minutes after arrest, equal numbers of swine received 6 mg/kg intravenous aminophylline (treatment group) and a saline solution placebo (control group), another minute of basic CPR, and standardized ACLS interventions beginning at 10 minutes. Initial resuscitation efforts were continued for at least 20 minutes. In all animals, if initial efforts failed, 6.0 mg/kg intravenous aminophylline, open label, and 10 minutes of additional resuscitation were administered. The primary outcome variables were return of spontaneous circulation (ROSC) and 1-hour survival. We compared groups with the two-tailed Fisher exact test. RESULTS: ROSC occurred in 4 of 12 animals in the treatment group (33%) and 3 of 12 in the control group (25%) (P=.50). Late administration of aminophylline did not result in ROSC in any animal. Survival to 1 hour was greater in the treatment group (4 of 12, 33%) than in the control group (1 of 12, 8%) (P=.16). CONCLUSION: Addition of aminophylline to standard ACLS interventions did not increase the incidence of ROSC or the 1-hour survival rate in a swine model of prolonged cardiac arrest.

Aminophylline↗

The knowledge and perceptions of medical personnel relating to outcome after cardiac arrest.

OBJECTIVE: We sought to evaluate the knowledge of probable outcome by medical personnel for in-hospital and out-of-hospital cardiac arrests, and self-reported history of CPR training referrals for family members of cardiac patients. METHODS: One hundred people from each of three population lists were randomly selected at a large, urban school of medicine and affiliated medical center: (1) year III and IV medical students; (2) residents in family medicine, emergency medicine, internal medicine, anesthesia, and surgery; (3) attending physicians in the same departments. A questionnaire was distributed that elicited estimates of in-hospital and out-of-hospital cardiac arrest (IHCA and OHCA, respectively) survival rates, and CPR training referral history. Estimates were compared against published data for accuracy (IHCA: 5-20%; OHCA 1-10%) RESULTS: The overall response rate was 63%. Accurate in-hospital cardiac arrest estimates [% (95% CI)] of survival were provided by 51.1% (36.8-63.4%), 47.3% (35.9-58.7%), and 36.7% (23.2-50.2%) of students, residents, and attending physicians, respectively. Accurate out-of-hospital estimates of survival were provided by 51.1% (36.8-63.4%), 52.1% (40.6-63.5%), and 70.8% (57.9-83.7%), respectively. Most thought that family members of cardiac patients ought to be CPR trained (92.6%). However, few had referred any for training in the past year (16.5%). There was strong support across respondent groups for including death notification information in the ACLS training program, with 80.4% of all respondents in favor. CONCLUSIONS: This study demonstrates that medical experience is not associated with accurate estimates of cardiac arrest survival. Overwhelmingly, medical personnel believe family members should be trained to perform CPR, however, few refer family members for CPR training.

Attitude of Health Personnel↗

Difference in survival after out-of-hospital cardiac arrest between the two largest cities in Sweden: a matter of time?

BACKGROUND: Dramatic differences in survival after out-of-hospital cardiac arrests (OHCA) reported from different geographical locations require analysis. We therefore compared patients with OHCA in the two largest cities in Sweden with regard to various factors at resuscitation and outcome. SETTING: All patients suffering an OHCA in Stockholm and Goteborg between 1 January 2000 and 30 June 2001, in whom cardiopulmonary resuscitation (CPR) was attempted were included in this retrospective analysis. RESULTS: All together, 969 OHCA in Stockholm and 398 in Goteborg were registered during the 18-month study period. There were no differences in terms of age, gender, and percentage of witnessed cases or percentage of patients who had received bystander CPR. However, the percentage of patients with ventricular fibrillation (VF) at arrival of the ambulance crew was 18% in Stockholm versus 31% in Goteborg (P <0.0001). The percentage of patients who were alive 1 month after cardiac arrest was 2.5% in Stockholm versus 6.8% in Goteborg (P=0.0008). Various time intervals such as cardiac arrest to calling for an ambulance, cardiac arrest to the start of CPR and calling for an ambulance to its arrival were all significantly longer in Stockholm than in Goteborg. CONCLUSION: Survival was almost three times higher in Goteborg than in Stockholm amongst patients suffering an OHCA. This is primarily explained by a higher occurrence of VF at the time of arrival of the ambulance crew, which in turn probably is explained by shorter delays in Goteborg. The reason for the difference in time intervals is most likely multifactorial, with a significantly higher ambulance density in Goteborg as one possible explanation.

Age Distribution↗

Out-of-hospital cardiac arrest: improved survival with paramedic services.

Survival after out-of-hospital cardiac arrest was studied in a suburban community (population 304000) before and after addition of paramedic services. During period 1 emergency medical technicians provided basic emergency care (cardiopulmonary resuscitation at the scene of collapse and during the journey to hospital). In period 2 additional care was given at the scene of collapse by paramedics capable of advanced emergency care (defibrillation, endotracheal intubation, drugs). During the 3-yr study 585 patients with cardiac arrest caused by heart disease received prehospital emergency resuscitation. Paramedic services improved the rate of live admission to the coronary-care or intensive-care unit from 19% to 34% (p less than 0.001) and the rate of discharge from 7% to 17% (p less than 0.01). The mean time from collapse to delivery of advanced emergency care was 27.5 min during period 1 with technician services, and 7.7 min during period 2 with paramedic services. Ventricular fibrillation caused cardiac arrest in nearly all patients who survived; it occurred in 91 of the 160 (57%) patients during period 1 whose rhythms were determined and in 192 of the 343 (56%) patients during period 2. The decreased time from collapse to delivery of advanced emergency care accounted for the improved survival with paramedic services.

Aged↗

Does hypoxia or hypercarbia independently affect resuscitation from cardiac arrest?

STUDY OBJECTIVE: In a previous cardiopulmonary resuscitation (CPR) study in swine, ventilation was associated with improved rate of return of spontaneous circulation (ROSC) compared with nonventilated animals, which had greater hypoxia and hypercarbic acidosis. We used the same model to determine the independent effect of hypoxia and hypercarbic acidosis on ROSC after cardiac arrest. DESIGN: Laboratory model of cardiac arrest. SETTING: University teaching hospital laboratory. PARTICIPANTS: Domestic swine (23 to 61 kg). INTERVENTIONS: Twenty-four swine were randomly assigned to three groups receiving ventilation during CPR with 85% O2/15% N2 (control), 95% O2/5% CO2 (hypercarbia), or 10% O2/90% N2 (hypoxia). All animals had ventricular fibrillation for 6 min without CPR, then CPR with one of the ventilation gases for 10 min, then defibrillation. Animals without ROSC received epinephrine, 85% O2, CPR for another 3 min, and defibrillation. MEASUREMENTS AND RESULTS: During the tenth minute of CPR, the hypercarbic group had more mean (SD) arterial hypercarbia than the control group (PCO2, 47 +/- 6, compared with 34 +/- 6; p < 0.01), and greater mixed venous hypercarbia (PCO2, 72 +/- 14, compared with 59 +/- 8; p < 0.05), while mean arterial and mixed venous PO2 was not significantly different. The hypoxic group had significantly less mean arterial (43 +/- 9 compared with 228 +/- 103 mm Hg) and mixed venous (22 +/- 5 compared with 35 +/- 7 mm Hg) PO2 when compared with the control group (p < 0.01), while mean arterial and mixed venous PCO2 were not significantly different. Thus, the model succeeded in producing isolated hypercarbia without hypoxia in the hypercarbic group and isolated hypoxia without hypercarbia in the hypoxic group. The rate of ROSC was 6/8 (75%) for the control group, 1/8 (13%) for the hypercarbic group, and 1/8 (13%) for the hypoxic group (p < 0.02). CONCLUSIONS: Both hypoxia and hypercarbia independently had an adverse effect on resuscitation from cardiac arrest. In this model with a prolonged interval of untreated cardiac arrest, adequate ventilation was important for resuscitation.

Analysis of Variance↗

Factors associated with survival to hospital discharge among patients hospitalised alive after out of hospital cardiac arrest: change in outcome over 20 years in the community of Göteborg, Sweden.

OBJECTIVE: To describe the change in survival and factors associated with survival during a 20 year period among patients suffering from out of hospital cardiac arrest and being hospitalised alive. PATIENTS: All patients hospitalised alive in the community of Göteborg after out of hospital cardiac arrest between 1 October 1980 and 1 October 2000 were included. METHODS: Patient data were prospectively computerised with regard to factors at resuscitation. Data on medical history and hospitalisation were retrospectively recorded. Patients were divided into two groups (the first and second 10 year periods). SETTING: Community of Göteborg, Sweden. RESULTS: 5505 patients suffered from cardiac arrest during the time of the survey. Among them 1310 patients (24%) were hospitalised alive. Survival (discharged alive) was 37.5% during the first part and 35.1% during the second part (NS). The following were independent predictors of an increased chance of survival: ventricular fibrillation/tachycardia as the first recorded rhythm (odds ratio (OR) 3.46, 95% confidence interval (CI) 2.36 to 5.07); witnessed arrest (OR 2.50, 95% CI 1.52 to 4.10); bystander initiated cardiopulmonary resuscitation (OR 2.00, 95% CI 1.42 to 2.80); the patient being conscious on admission to hospital (OR 6.43, 95% CI 3.61 to 11.45); sinus rhythm on admission to hospital (OR 1.53, 95% CI 1.12 to 2.10); and treatment with lidocaine in the emergency department (OR 1.64, 95% CI 1.16 to 2.31). The following were independent predictors of a low chance of survival: age > 70 years (median) (OR 0.65, 95% CI 0.47 to 0.88); atropine required in the emergency department (OR 0.35, 95% CI 0.16 to 0.75); and chronic treatment with diuretics before hospital admission (OR 0.59, 95% CI 0.43 to 0.81). CONCLUSION: There was no improvement in survival over time among initial survivors of out of hospital cardiac arrest during a 20 year period. Major indicators for an increased chance of survival were initial ventricular fibrillation/tachycardia, bystander cardiopulmonary resuscitation, arrest being witnessed, and the patient being conscious on admission. Major indicators for a lower chance were high age, requirement for atropine in the emergency department, and chronic treatment with diuretics before cardiac arrest.

Adolescent↗

Prevalence of silent myocardial ischemia in survivors of cardiac arrest.

The prevalence and type of ischemia (silent vs painful) in survivors of cardiac arrest not associated with acute myocardial infarction were studied to test the hypothesis that survivors may have an increased prevalence of silent ischemia. Of 48 survivors of cardiac arrest over a 4-year period who had undergone exercise testing, 24 met inclusion criteria. These 24 subjects had documented ventricular fibrillation and coronary artery disease proven by cardiac catheterization or a previous electrocardiographic pattern of myocardial infarction. Thirteen of 24 (54%) had a positive treadmill stress test (greater than or equal to 1.0 mm flat or downsloping ST depression). The mean resting left ventricular ejection fraction was 43%. Nine of 11 patients (82%) who had exercise radionuclide studies performed had ischemic abnormalities (less than 5% increase in left ventricular ejection fraction with new or worsened wall motion abnormalities). Thus, 16 of 24 (67%) had a positive treadmill stress test or radionuclide ventriculogram. Only 1 of 16 (6%) had painful ischemia (p less than 0.001 relative to an even distribution of painful vs painless ischemia). Thus, survivors of cardiac arrest have a high prevalence of exercise-induced ischemia, and in most the ischemia is silent.

Coronary Disease↗