Paroxysmal atrial fibrillation occurs often in cryptogenic ischaemic stroke. Final results from the SURPRISE study.

BACKGROUND AND PURPOSE: Atrial fibrillation (AF) increases the risk of stroke fourfold and is associated with a poor clinical outcome. Despite work-up in compliance with guidelines, up to one-third of patients have cryptogenic stroke (CS). The prevalence of asymptomatic paroxysmal atrial fibrillation (PAF) in CS remains unknown. The SURPRISE project aimed at determining this rate using long-term cardiac monitoring. METHODS: Patients with CS after protocolled work-up including electrocardiography (ECG) and telemetry were included after informed consent. An implantable loop recorder (ILR) was implanted subcutaneously. PAF was defined by events of atrial arrhythmia >2 min with a correlating one-lead ECG confirming the diagnosis. RESULTS: Eighty-five patients were monitored for a mean of 569 days (SD ±310). PAF was documented in 18 patients (20.7%) during the study period and detected by ILR in 14 patients (16.1%). In three patients PAF was detected by other methods before or after monitoring and was undiscovered due to device sensitivity in one case. The first event of PAF was documented at a mean of 109 days (SD ±48) after stroke onset. PAF was asymptomatic in all cases and occurred in episodes lasting predominantly between 1 and 4 h. Four recurrent strokes were observed, three in patients with PAF; all three patients were on oral anticoagulation (OAC). CONCLUSIONS: One in five patients with CS had PAF, which occurred at low burden and long after stroke. Future studies should determine the role of implantable cardiac monitors after stroke and determine the potential therapeutic benefit of OAC treatment of patients with PAF.

[Prognostic values of echocardiography compared with clinical variables in suspected heart disease. Multivariate analysis of long-term prognosprognosis in 456 patients]. / Prognostisk vaerdi af ekkokardiografi sammenlignet med kliniske variabler ved mistaenkt hjertesygdom. Multivariat analyse of langtidsprognosen hos 456 patienter.

The aim of the study was to evaluate the prognostic significance of clinical and echocardiographic data in patients referred for echocardiography in a retrospective analysis. Four hundred and fifty-six patients from a district hospital were studied. Survival after three years was 64%. Multivariate analysis identified five factors with independent prognostic information (relative risks of death are shown in brackets): left ventricular wall motion index (WMI) < or = 1.2 by echocardiography (2.5), status as in-patient (2.1), age > 65 years (1.7), clinical heart failure (1.9) and atrial fibrillation (1.5). When information on age, hospitalisation status, heart failure and heart rhythm had already been entered in the Cox model, echocardiographic results such as decreased WMI and dilated right ventricle still gave further prognostic information. We conclude that among conventional clinical and echocardiographic data WMI was the strongest predictor of long-term survival, and, despite prior knowledge of major clinical features, echocardiography provided further prognostic information.

Prognostic value of echocardiography compared to other clinical findings. Multivariate analysis based on long-term survival in 456 patients.

The prognostic significance of conventional clinical and echocardiographic data in patients referred to echocardiography was retrospectively analyzed. 456 patients (206 females and 250 males) were studied in the department of cardiology in a district hospital. Survival after 3 years was 64%. By multivariate analysis five factors contained independent, significant, prognostic information (hazard ratios for death are given in parentheses): left ventricular wall motion score index (WMI) < or = 1.2 by echocardiography (2.5), status as inpatient (2.1), age > 65 years (1.7), clinical heart failure (1.9) and atrial fibrillation (1.5). A stepwise multivariate analysis was performed by entering variables into a model initially forced to contain information on age, hospitalization status, treatment of heart failure and heart rhythm. In this analysis, a poor WMI (< or = 1.2) and a dilated right ventricle contained further independent prognostic information. In conclusion, among conventional clinical and echocardiographic data, WMI was the most powerful predictor of long-term survival, and despite knowledge of major clinical features echocardiography provided further prognostic information.

[The 24-hour heart rate variability. An important predictor of sudden death after myocardial infarction]. / 24 timers hjertefrekvensvariabilitet. En vigtig risikofaktor for pludselig død efter myokardieinfarkt.

The activity of the cardiac autonomic nervous system can be estimated by measurement of beat to beat variations in heart rate-heart rate variability (HRV). In survivors after myocardial infarction, reduced 24-hour HRV, is an independent predictor of mortality/sudden cardiac death. The attenuated HRV is presumed to indicate reduced vagal function and concomitant high sympathetic activity. In experimental studies, this combination reduces the threshold for inducing malignant tachyarrhythmias, and is very probably a clinically important factor for the evolution of ventricular arrhythmias. Measurement of HRV in ordinary 24-hour ECG recordings can, together with other non-invasive measurements, stratify arrhythmic risk in survivors of myocardial infarction.

[Serotonin and cardiovascular control]. / Serotonin og kardiovaskulaer kontrol.

Serotonin is a monoamine and is widely distributed in the human organism. Serotonin is synthesized from the amino acid tryptophane and is broken down via mono-amino-oxydase enzymes to 5-hydroxy-indol-acetic acid and by acetylizing and methylizing to melantonin. In 1986, a consensus concerning the classification of the serotonergic receptors was established. Three main classes were determined, viz: 5-HT1, 5-HT2 and 5-HT3. 5-HT1 receptors were further subdivided into A, B, C and D-receptors and, of these, the 5-HT1A-receptor is involved in the centrally mediated blood pressure control via reduction in the pre- and postganglionic sympathetic activity. The 5-HT2 receptors are primarily involved in control of peripheral blood pressure where agonizing results in vascular contraction of the large arteries and veins and thrombocyte aggregation. The 5-HT1 receptors are also involved peripherally in connection with release of relaxing factors derived from endothelium. In vitro and in animal experiments, it has been demonstrated that serotonin is capable of inducing arrhythmia and myocardial dysfunction via 5-HT3 receptors. Several preparations with effects on both the central and peripheral serotonergic receptors are already marketed for treatment of hypertension and other conditions.

Magnesium and acute myocardial infarction. Transient hypomagnesemia not induced by renal magnesium loss in patients with acute myocardial infarction.

Serum magnesium concentrations and the rate of urine magnesium excretion were studied in 24 patients with suspected acute myocardial infarction (AMI). Blood and urine samples were taken on admission, at three-hour intervals for the first 24 hours after admission, and every eight hours for the next 24 hours. Thirteen of the patients were found to have AMI, and the 11 who did not have AMI served as a control. During the first 32 hours, the AMI group had significantly low serum magnesium concentrations. The serum magnesium concentrations were unchanged in the control group. Results of the urine samples disproved our hypothesis that the drop in serum magnesium concentrations was due to an increased renal magnesium loss. These results indicate a magnesium migration associated with AMI, from extracellular to intracellular space.