Mood and transient cardiac dysfunction in everyday life

Emotion in daily life may be associated with transient myocardial ischemia, ventricular tachycardia and impaired autonomic function in cardiac patients, but the precise temporal sequence is unclear. Eighty-eight patients with suspected coronary artery disease underwent 24-h electrocardiographic monitoring, and affect was measured with the Day Reconstruction Method. Thirteen patients (15%) experienced one or more episodes of ST depression or ventricular tachycardia, nine of whom provided concurrent mood data. Mood and heart rate variability were analyzed for the 15 min before, during, and 15 min after each ST depression/ventricular tachycardia episode, and were compared with control periods not associated with cardiac dysfunction. Patients reported more negative mood in the 15 min preceding cardiac dysfunction compared with control periods (P = 0.02). Heart rate increased in the 5 min before cardiac dysfunction (P = 0.005), whereas low frequency heart rate variability was reduced at onset but not before cardiac dysfunction (P = 0.007). There were not changes in high frequency heart rate variability. This small study indicates that emotional state may contribute to vulnerability of cardiac dysfunction in everyday life

Complex systems and the technology of variability analysis

Characteristic patterns of variation over time, namely rhythms, represent a defining feature of complex systems, one that is synonymous with life. Despite the intrinsic dynamic, interdependent and nonlinear relationships of their parts, complex biological systems exhibit robust systemic stability. Applied to critical care, it is the systemic properties of the host response to a physiological insult that manifest as health or illness and determine outcome in our patients. Variability analysis provides a novel technology with which to evaluate the overall properties of a complex system. This review highlights the means by which we scientifically measure variation, including analyses of overall variation (time domain analysis, frequency distribution, spectral power), frequency contribution (spectral analysis), scale invariant (fractal) behaviour (detrended fluctuation and power law analysis) and regularity (approximate and multiscale entropy). Each technique is presented with a definition, interpretation, clinical application, advantages, limitations and summary of its calculation. The ubiquitous association between altered variability and illness is highlighted, followed by an analysis of how variability analysis may significantly improve prognostication of severity of illness and guide therapeutic intervention in critically ill patients

Beta adrenergic blockade in the treatment of sustained ventricular tachycardia or ventricular fibrillation

The value of beta-blockers as antiarrhythmic drugs in patients with sustained VT or VF has received only little attention. This article summarizes the current state of knowledge regarding the identification of patients with sustained VT or VF with the highest benefit of beta-blockade. The antiarrhythmic mechanisms of beta-blockade and its efficacy as single or adjuvant therapy in patients with sustained VT or VF are reviewed. Current insights into the effects of beta-blockade in patients suffering from VT, in particular in the setting of heart failure, are discussed and future directions are considered

THE CLINICAL-SIGNIFICANCE OF CORONARY ANATOMY IN POST-INFARCT PATIENTS WITH LATE SUSTAINED VENTRICULAR-TACHYCARDIA OR VENTRICULAR-FIBRILLATION

The role of ischaemia in post-infarct patients with ventricular tachyarrhythmias is not firmly established Using coronary angiography, 82 post-infarct patients with sustained ventricular tachycardia or fibrillation were subclassified into three groups. Fourteen patients (17%) had significant coronary artery disease, suggesting that ischaemia was the primary cause (group A). In 13 patients (16%) ischaemia was considered a coexistent factor (group B). In 55 patients (67%) ischaemia did not play a role (group C). The 1-year cumulative arrhythmia-free rate was 100%, 75%, 68% and the 2-year arrhythmia-free rate 100%, 56%, 52% for groups A, B and C, respectively. Using life-fable analysis, group A had the most favourable long-term outcome in relation to arrhythmia recurrence Outcomes of groups B and C were comparable. In a univariate analysis, arrhythmia recurrence was determined by the arrhythmogenic role of ischaemia, the left ventricular ejection fraction and the time from the old infarct to the index arrhythmia. In the absence of arrhythmic events in group A, multivariate analysis of groups B and C identified depressed ejection fractions (RR 0.69, CI 0.49-0.98) and a prolonged time interval from the last infarct (>5 years, RR 2.53, CI 1.12-5.75) as independent predictors for arrhythmia recurrence. The present approach helps in the identification of post-infarct patients with ventricular tachycardia and fibrillation, who benefit from stand-alone anti-ischaemic therapy. If ischaemia does not play a major arrhythmogenic role, prognosis depends on the left ventricular ejection fraction and on the age of the previous infarct. Despite adequate anti-ischaemic therapy, prognosis remains poor if the ejection fraction is below 40% or the infarct occurred more than 5 years before

ASSOCIATION BETWEEN REDUCED HEART-RATE-VARIABILITY AND LEFT-VENTRICULAR DILATATION IN PATIENTS WITH A FIRST ANTERIOR MYOCARDIAL-INFARCTION

Background-Reduced heart rate variability has been identified as an important prognostic factor after myocardial infarction. This factor is thought to reflect an imbalance between sympathetic and parasympathetic activity, which may lead to unfavourable loading conditions and thus promote left ventricular dilatation. Patients and methods-298 patients in a multicentre clinical trial were randomised to captopril or placebo after a first anterior myocardial infarction. All patients were treated with streptokinase before randomisation. In the present substudy full data including heart rate variability and echocardiographic measurements were available from 80 patients. Patients were divided into two groups: those with a reduced (less than or equal to 25) heart rate variability index and those with normal heart rate variability index (> 25). Heart rate variability was evaluated by 24 h Holter monitoring before discharge. Left ventricular volumes were assessed by echocardiography before discharge and three and 12 months after myocardial infarction. Extent of myocardial injury, severity of coronary artery disease, functional class, haemodynamic variables, and medication were also considered as possible determinants of left ventricular dilatation. Results-Before discharge end systolic and end diastolic volumes were not different in the two groups. After 12 months in patients with a reduced heart rate variability, end systolic volume (mean (SD)) had increased by 6 (14) ml/m(2) (P = 0.043) and end diastolic volume had increased by 8 (17) ml/m(2) (P = 0.024). Left ventricular volumes were unchanged in patients with a normal heart rate variability. Also, patients with left ventricular dilatation had a larger enzymatic infarct size and higher heart rates and rate-pressure products. A reduced heart rate variability index before discharge was an independent risk factor for left ventricular dilatation during follow up. Measurement of heart rate variability after three months had no predictive value for this event. Conclusion-Assessment of the heart rate variability index before discharge, but not at three months, gave important additional information for identifying patients at risk of left ventricular dilatation