Prognostic value of ambulatory electrocardiography monitoring in patients with dilated cardiomyopathy

High Nighttime Heart Rate is Associated with Increased Risk of All-Cause Mortality in Patients with Heart Failure and Reduced Ejection Fraction

High heart rate (HR) is associated with increased risks of adverse outcomes in patients with heart failure. This study aimed to evaluate which measures of HR were associated with all-cause mortality in patients with heart failure and reduced ejection fraction (HFrEF). This study involved 741 HFrEF patients (age 65.1 ± 14.7 years, 71% male) who underwent 24 hour Holter electrocardiogram and resting electrocardiogram within 7 days between 2011 and 2015. We examined the associations of resting, 24 hour, and nighttime HRs with all-cause mortality. Nighttime and 24 hour HRs were determined as the mean HRs between 11:00 p.m. and 7:00 a.m. and over 24 hours, respectively. Nighty patients (12.1%) died during the 2-year follow-up. Resting, nighttime, and 24 hour HRs were significantly associated with all-cause mortality, also after adjusting for conventional risk factors. Resting HR did not remain as an independent factor when 24 hour HR (hazard ratio 1.10, 95% confidence interval 1.04-1.18) was included in the model. Including nighttime HR (hazard ratio 1.11, 95% confidence interval 1.05-1.17) in the model also eliminated 24 hour HR as an independent variable. Compared with the lowest quartile of nighttime HR (< 65 beats/minute), the highest quartile of nighttime HR (> 87 beats/minute) was significantly associated with a higher risk of all-cause mortality (hazard ratio 2.89, 95% CI 1.49-5.60). In conclusion, 24 hour HR and nighttime HR were significantly associated with an increased risk of mortality in patients with HFrEF. Nighttime HR appeared to be more strongly associated with all-cause mortality compared with 24 hour HR.

Standard Deviation of normal interbeat intervals as a risk marker in patients with left ventricular systolic dysfunction: a meta-analysis

Our aim was to evaluate the Standard Deviation of Normal-Normal (SDNN) interbeat interval as a risk marker in left ventricular systolic dysfunction (LVSD) patients through a meta-analysis. We searched PubMed for studies that evaluated SDNN as a predictor of all-cause-death, cardiac death, transplantation, and progressive clinical deterioration using a search strategy validated for MEDLINE. Mean values and SD for SDNN in sixteen studies included were 115+/-48 ms in survivors versus 87+/-40 ms in non-survivors, resulting in a statistically significant standardized mean difference (0.594, 95%CI 0.385 to 0.803). In conclusion, SDNN may be a useful prognostic marker in LVSD. Additional studies must evaluate if SDNN may be used to subsidize therapeutic decisions.

[Long term electrocardiography (Holter monitoring)]

During the past almost 50 years Holter monitoring has become an established non-invasive diagnostic tool in clinical electrophysiology. It allows ECG recording independent of stationary monitoring facilities during daily life and, therefore, contains much information. In the beginning the main interest was directed towards quantitative and qualitative assessment of arrhythmias, their circadian behaviour, and the circadian behaviour of the heart rate. With advances in technology the analysis spectrum of Holter monitoring expanded, and it was used also for detection of silent myocardial ischaemia. New digital recorders and computers with large capacities made it possible to measure every single heart beat very accurately, which was a prerequisite for heart rate variability and QT-interval analysis, which provided new knowledge about the autonomic modulation of the heart rate and the circadian dynamicity of the QT interval, respectively. Beyond arrhythmia analysis Holter monitoring was increasingly used to assess prognosis in different cardiac conditions. It can also be valuable in assessing transient symptoms possibly related to arrhythmias or device dysfunction, which will not necessarily be revealed by simple device control.

A comprehensive approach to management of ventricular arrhythmias

This review presents five cases that highlight the complexity of taking care of patients with ventricular arrhythmias. Three of the cases discuss management of patients with nonsustained ventricular tachycardia in the setting of structural heart disease: dilated cardiomyopathy, hypertrophic cardiomyopathy, and after myocardial infarction. A fourth case asks whether data from implantable cardioverter defibrillator (ICD) trials can be extrapolated to older patients, and the fifth case discusses management of recurrent ventricular arrhythmias in a patient with an ICD.