Ambulatory ECG (AECG) is very commonly employed in a variety of clinical contexts to detect cardiac arrhythmias and/or arrhythmia patterns which are not readily obtained from the standard ECG. Accurate and timely characterization of arrhythmias is crucial to direct therapies that can have an important impact on diagnosis, prognosis or patient symptom status. The rhythm information derived from the large variety of AECG recording systems can often lead to appropriate and patient-specific medical and interventional management. The details in this document provide background and framework from which to apply AECG techniques in clinical practice, as well as clinical research.
The aim of this study was to assess the effects of 5 mg melatonin before sleep in patients with coronary artery disease (CAD) and with an abnormal circadian pattern of blood pressure (BP) on changes in circadian BP profile and heart rate variability (HRV). Sixty patients with CAD, nondippers aged 48-80 years (male 75%), were included. In addition to previous treatment, they were randomly allocated to melatonin or placebo. After 90 days, a second 24-h BP monitoring was carried out. Each patient had two sessions (before randomization and at the end of study) of 24-h ECG monitoring to assess the changes in HRV. Inclusion of melatonin led to BP pattern normalization in 35% of patients in the melatonin group and in 15% of controls (P¼0.609). This effect was reached not only by a decrease in nighttime BP, but also by an increase in daytime BP (significant in the melatonin group). A nonoptimal effect for BP profile was observed in 12.5% of patients: extreme-or reverse dippers. In patients with conversion from nondippers to dippers (responders), an increase in standard deviation of normal-to-normal intervals between initial and final HRV analyses was observed. Nonresponders represented an increase in the mean circadian heart rate. To avoid nonoptimal effects, the inclusion of melatonin in pharmacotherapy of patients with CAD should be based on monitoring of circadian BP profile, before and during treatment. As melatonin caused not only a nocturnal decrease in BP but also a daytime increase, it should not be recommended in patients with 'high normal' values of BP because of the danger of induction of arterial hypertension.
Besides the evolution of mitral inflow toward the delayed relaxation profile in elderly, a decrease of propagation and tissue Doppler velocities were documented. The strongest positive correlation with age was observed for atrial velocity of mitral inflow (A, r = 0.63) and inverse correlation for E/A ratio (r =-0.6) and early diastolic velocity of mitral annulus (r =-0.69).
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