Out-of-hospital cardiac arrest: Causes according to autopsy and electrocardiography - Analysis of 781 patients with neither hospital care nor prescribed medication during the preceding two years.

BACKGROUND: There is a knowledge gap regarding aetiology of and potential for predicting out-of-hospital cardiac arrest (OHCA) among individuals who are healthy before the event. AIM: To describe causes of OHCA and the potential for predicting OHCA in apparently healthy patients. METHODS: Patients were recruited from the Swedish Register of Cardiopulmonary Resuscitation from November 2007 to January 2011. Inclusion criteria were: OHCA with attempted CPR but neither dispensed prescription medication nor hospital care two years before the event The register includes the majority of patients suffering OHCA in Sweden where cardiopulmonary resuscitation (CPR) was attempted. Medication status was defined by linkage to the Swedish Prescribed Drug Register. Cause of death was assessed based on autopsy and the Swedish Cause of Death Register. Prediction of OHCA was attempted based on available electrocardiograms (ECG) before the OHCA event. RESULTS: Altogether 781 individuals (16% women) fulfilled the inclusion criteria. Survival to 30 days was 16%. Autopsy rate was 72%. Based on autopsy, 70% had a cardiovascular aetiology and 59% a cardiac aetiology. An ECG recording before the event was found in 23% of cases. The ECG was abnormal in 22% of them. CONCLUSION: Among OHCA victims who appeared to be healthy prior to the event, the cause was cardiovascular in the great majority according to autopsy findings. A minority had a preceding abnormal ECG that could have been helpful in avoiding the event.

The prevalence of atrial fibrillation in a geographically well-defined population in northern Sweden: implications for anticoagulation prophylaxis.

OBJECTIVES: The aims of this study were to evaluate the community-based prevalence of atrial fibrillation (AF) in a western society using a geographically well-defined population in the northern part of Sweden as a reference and to estimate the proportion of patients eligible for oral anticoagulation (OAC) prophylactic therapy according to the stroke risk indices CHADS2 and CHA2 DS2 -VASc. Bleeding risk was assessed using the HAS-BLED score. DESIGN: The study population was recruited from AURICULA, a Swedish national quality register for patients receiving anticoagulation treatment. All patients with the diagnosis AF in the catchment area are registered in AURICULA. RESULTS: Of the 65 532 inhabitants in the catchment area, 1616 were diagnosed with AF (1200 cases were characterized as chronic AF). Thus, the overall prevalence of AF was 2.5%. The prevalence increased with age from 6.3% in patients over 55 years of age to 13.8% in those over 80 years. The prevalence was higher in men than in women in all age groups. Overall, 56.3% and 85.1% of the population were at high risk of stroke (≥2 points) according to CHADS2 and CHA2 DS2 -VASc, respectively. In addition, 26.9% had an increased bleeding risk according to HAS-BLED. CONCLUSION: Within this large Caucasian population, we identified the highest community-based prevalence of AF to date. The prevalence was strongly associated with increasing age and male gender. Using CHA2 DS2 -VASc instead of CHADS(2) widened the indication for OAC prophylactic therapy of AF in this population.

A comparison of metoprolol and morphine in the treatment of chest pain in patients with suspected acute myocardial infarction--the MEMO study.

OBJECTIVES: To compare the analgesic effect of metoprolol and morphine in patients with chest pain due to suspected or definite acute myocardial infarction after initial treatment with intravenous metoprolol. DESIGN: All patients, regardless of age, admitted to the coronary care unit at Uddevalla Central Hospital due to suspected acute myocardial infarction were evaluated for inclusion in the MEMO study (metoprolol-morphine). The effects on chest pain and side-effects of the two treatments were followed during 24 h. Pain was assessed by a numerical rating scale. RESULTS: A total of 265 patients were randomized in this prospective double-blind study and 59% developed a confirmed acute myocardial infarction. In both treatment groups, there were rapid reductions of pain intensity. However, in the patient group treated with morphine, there was a more pronounced pain relief during the first 80 min after start of double-blind treatment. The side-effects were few and were those expected from each therapeutic regimen. During the first 24 h, nausea requiring anti-emetics was more common in the morphine-treated patients. CONCLUSION: In suspected acute myocardial infarction, if chest pain persists after intravenous beta-adrenergic blockade treatment, standard doses of an opioid analgesic such as morphine will offer better pain relief than increased dosages of metoprolol.

Effects and pharmacokinetics of high dose metoprolol on chest pain in patients with suspected or definite acute myocardial infarction.

OBJECTIVE: Pain intensity and the plasma concentrations of metoprolol and its major metabolite alpha-hydroxymetoprolol as well as noradrenaline (NA), adrenaline (A) and neuropeptide Y (NPY) were determined in patients with pain due to definite or suspected acute myocardial infarction (AMI) after graded metoprolol infusion. Pain intensity and metoprolol kinetics were assessed over 8 h. METHODS: Twenty-seven patients of either sex, aged 48-84 years with ongoing chest pain upon arrival to the Coronary Care Unit (CCU) were subdivided into two groups: (1) patients with ECG signs of threatening transmural myocardial damage (n = 15); and (2) patients without such ECG signs (n = 12). Pain intensity was assessed by a numerical rating scale (NRS) and venous blood was obtained for determination of plasma catecholamine and NPY concentrations. A continuous infusion of metoprolol (3 mg.min-1 i.v) was started and serial blood samples for plasma catecholamines, NPY as well as metoprolol and its major metabolite alpha-hydroxymetoprolol were obtained from the contralateral arm. RESULTS: Initial pain intensity was 5.9 (arbitrary units) and 5.4 in the groups with and without signs of transmural myocardial damage, respectively. One third of the patients with ST changes reported full pain relief (NRS = 0) within 70 min after starting metoprolol infusion (accumulated dose, 15-180 mg). Among the patients without ST changes upon arrival, full pain relief was obtained in 70% (accumulated dose, 30-120 mg). There was a dose-dependent relation between accumulated metoprolol dose and pain relief. The diagnosis of acute myocardial infarction (AMI) was confirmed in all 15 patients with ECG signs on arrival of transmural myocardial damage. The mean metoprolol dose in this group was 91(12) mg. The mean metoprolol dose in the 12 patients without ST changes was 64(8) mg. In all, seven of these patients developed definite AMI. The terminal half-life of unchanged metoprolol ranged from 2.5 to 8.5 h in group 1 and from 2.2 to 5.2 h in group 2. In group 1, metoprolol half-life was 4.5 h and total plasma clearance (CL) 54.1 1.h-1. In group 2, the metoprolol half-life was 3.7 h and total plasma clearance 75.4 1.h-1. There was a significant difference in clearance between the groups. After the intravenous metoprolol infusion, alpha-hydroxymetoprolol concentrations increased gradually. In groups 1 and 2, maximal concentrations in plasma (Cmax) were 143 and 135 nmol.1(-1) for alpha-hydroxymetoprolol and 2830 and 1653 nmol.1(-1) for metoprolol, respectively. Plasma NA or NPY did not differ between the groups. In contrast, plasma A was significantly higher during the initial 90 min of observation in patients with ECG signs of transmural myocardial damage. CONCLUSION: High-dose intravenous metoprolol was well tolerated in patients with suspected AMI. There was a more rapid and almost complete pain relief in patients without signs of transmural ischaemia compared with the patients with ECG signs of transmural AMI at arrival. In the later group of patients, plasma clearance of metoprolol was significantly reduced.

Arterial embolism and atrial arrhythmias.

In a retrospective study, the frequency of atrial arrhythmias of types known to cause systemic embolisation and the effect of anticoagulant treatment were studied in 106 patients with arterial embolism. Such embolising arrhythimas were found in 84 patients (79%). Permanent atrial fibrillation was documented in 53 patients (50%) and episodic atrial arrhythmia was encountered in 28 patients (26%). In 21 of 28 patients with sinus rhythm on admission, an embolising arrhythmia could be identified in previous ECG recordings. Patients with atrial arrhythmias had a significantly higher rate of prior embolic episodes and embolic events during follow-up (53 events in 84 patients) compared to the patients without arrhythmia (6 events in 22 patients) (P less than 0.05). In patients with atrial arrhythmias postoperative treatment with peroral anticoagulation was associated with a lower mortality (P less than 0.003) and a lower rate of reembolisation and stroke (P less than 0.0005). It is concluded that every fourth patient presenting with arterial embolism had an atrial arrhythmia of episodic nature. Most of these patients had normal sinus rhythm on admission but could be identified in previous ECG recordings. This study suggests that patients with arterial embolism and atrial arrhythmia have a higher risk of further embolisation with an ensuing risk of morbidity and death, compared to patients without arrhythmia. A positive effect of anticoagulation seemed to be present in patients with atrial arrhythmia whereas such a positive effect could not be identified in patients without arrhythmia.

Athlete's bradycardia as an embolising disorder? Symptomatic arrhythmias in patients aged less than 50 years.

One hundred and sixty consecutive patients less than 50 years of age (mean 38 years) referred for long term electrocardiographic recording were evaluated retrospectively. Significant cardiac arrhythmias were detected in 51 of 107 (48%) patients examined because of syncope or dizzy spells or both. Of 39 patients examined for cardiac complaints or presumed complex arrhythmias, 15 (38%) had significant arrhythmias. Of 14 patients examined because of otherwise unexplained strokes, nine had slow sinus rates. Of these, one patient had recently undertaken moderately intensive athletic activity and four had been undertaking vigorous athletic activities for several years. All of the 12 active athletes who were followed up on account of syncope or dizzy spells were free of symptoms after reducing their athletic activities. The cardiac rhythm returned to normal in four out of five who underwent repeat long term electrocardiographic recording. It is suggested that vigorous athletic activity in subjects of 30-50 years of age may transform the adaptative bradycardia of the athlete into a condition similar to the embolising sick sinus syndrome.

Diagnosis of ventricular tachyarrhythmias by ambulatory electrocardiographic monitoring. Correlation with his bundle electrography.

The aim of the present study was to compare the prediction of bradyarrhythmias via the corrected sinus node recovery time and the His bundle electrogram with the findings made during long term electrocardiographic recording. Ninety-two patients, aged 17-88 years, were included in the study with a suspicion of Adams-Stokes' syndrome. During long term electrocardiographic recording only 40 patients had symptoms while 52 could not tolerate long term electrocardiographic recording until symptoms had appeared. Seven out 37 patients with sick sinus syndrome and 2 out of 9 with atrioventricular block 2 degrees/3 degrees had additional significant ventricular arrhythmias. A total of 10 patients had prolonged (greater than or equal to 160 msec) atrium to His intervals, among them 2 had significant ventricular arrhythmia but failed to have symptoms during long term electrocardiographic recording. In 22 patients the His to ventricle interval was moderately prolonged (56-79 msec), among them 7 had significant ventricular arrhythmias (5 with symptoms during long term electrocardiographic recording). Out of 5 patients with markedly H-V interval prolonged, 3 patients had 2 degrees/3 degrees atrio-ventricular block and 1 patient had atrial tachyarrhythmia during long term electrocardiographic recording. In conclusion prolonged H-V intervals are frequent in patients with episodic atrioventricular block but also in patients who have symptomatic ventricular tachyarrhythmias. Long term electrocardiographic recording is essential for the differentiation between symptomatic ventricular arrhythmia and symptomatic atrioventricular block in patients with prolonged HV-intervals.

Is occult atrial disorder a frequent cause of non-hemorrhagic stroke? Long-term ECG in 86 patients.

To assess the importance of occult atrial disorder with possible embolization as a cause of non-hemorrhagic stroke, 68 patients with neurologic symptoms lasting 24 hours or more and 18 patients with transient ischemic attacks were examined by long-term electrocardiographic recording (LTER). Lacking matched controls we used a reference population of 103 elderly subjects selected at random from the general population for a previous LTER study. Permanent or episodic atrial arrhythmias of types known to cause cerebral embolization were detected by LTER in 32 (47%) of the 68 patients with a clinical diagnosis of cerebral embolization or thrombosis and in 6 (33%) of the 18 patients with transient ischemic attacks. Of the 38 patients with atrial arrhythmia during LTER 17 had such arrhythmias in their standard ECGs. This frequency of atrial arrhythmias during LTER differs from that of the reference population (p less than 0.025). Thirteen of 16 patients with multiple cerebral lesions had signs of atrial arrhythmia during LTER. Patients having occult atrial disorder with episodic atrial arrhythmia may be an important and common risk group for non-hemorrhagic stroke in addition to the previously recognized group of patients with atrial arrhythmia detectable in the standard ECG. LTER may be important in the evaluation of patients with unexplained stroke.

Predictive use of routine 24-hour electrocardiography in suspected Adams-Stokes syndrome. Comparison with cardiac rhythm during symptoms.

Using strictly defined criteria of significant arrhythmias, long term electrocardiographic recording has been evaluated for confirmation of arrhythmias as the cause of cerebral symptoms in 81 patients with suspected Adams-Stokes syndrome. Extension of long term electrocardiographic recording for more than 24 hours gives marginal additional information at a high cost. Among 43 patients monitored until symptoms appeared, non cardiogenic causes were confirmed in 20 of 22 patients because the recording showed normal rhythm during symptoms. Fifteen of 21 patients with a significant arrhythmia during an asymptomatic 24 hour recording later had the same arrhythmia during symptoms. Of 38 patients who failed to develop symptoms, 21 had a significant arrhythmia detectable within 24 hours and 23 when 48 hours of recording were analysed.

Frequency and distribution of long-term ECG-recorded cardiac arrhythmias in an elderly population. With special reference to neurological symptoms.

The prevalence of serious episodic cardiac arrhythmias known to correlate with cerebral symptoms was investigated in 103 elderly, randomly selected persons with the aid of 22 hours of long-term ECG recording (LTER). Twelve of 26 subjects with dizziness/syncope had serious episodic arrhythmias compared with 5 of 77 subjects without these symptoms. This difference is significant (p less than 0.001). Five patients fulfilled strict criteria for pacemaker treatment of symptomatic bradycardias. Three had the sick sinus syndrome and two had third degree atrioventricular block. In 4 subjects, drugs were withdrawn due to bradycardia; and 4 were treated for tachyarrhythmias. Despite the finding of minor arrhythmnias in almost all asymptomatic subjects, it is concluded that serious episodic arrhythmias in the elderly are related to cerebral symptoms. It is also concluded that these arrhythmias are more common than previously believed and that LTER should be widely used.

Episodic cardiac arrhythmia and accident rate.

The rate of accidents severe enough to require a roentgen examination was investigated in a series of patients with episodic cardiac arrhythmia of types causing Adams-Stokes' syndrome. The accident rate was doubled compared with controls without known Adams-Stokes' syndrome but the associated increase in fracture rate was not significant.

Episodic cardiac arrhythmia and femoral neck fracture.

Fifty-eight consecutive patients admitted to hospital for fracture of the upper end of the femur were examined by continuous ECG monitoring for 22--24 hours. More than one third of the patients had occult, previously unknown episodic arrhythmias severe enough to cause dizzy spells and syncope. These patients had more often a history of dizziness and syncope and could less frequently than patients without serious arrhythmias return to their homes at the time of discharge despite uncomplicated fracture treatment.

High pacemaker implantation rate following "cardiogenic neurology".

This paper gives data on symptomatic patients with bradycardia found not at random but as the result of greatly expanded facilities for recognition of arrhythmias. The incidence of patients with symptomatic bradycardia was very high. Most patients had intermittent arrhythmias and diagnosis was often only possible after long-term ECG screening. Symptoms were as severe, and relief of symptoms with treatment was as good, as in pacemaker-treated patients described by others. Our conclusion is that indications for arrhythmia screening should be increased, as the diagnosis and treatment are very worthwhile. We refer to the systematized active diagnosis and treatment of arrhythmias in patients with cerebral symptoms as cardiogenic neurology.