The changing circumstance of atrial fibrillation - progress towards precision medicine.

The prevalence of atrial fibrillation (AF) in the general population is between 1% and 2% in the developed world and is higher in men than in women. The arrhythmia occurs much more commonly in the elderly, and the estimated lifetime risk of developing AF is one in four for men and women aged 40 years and above. Projected data from multiple population-based studies in the USA and Europe predict a two- to threefold increase in the number of AF patients by 2060. The high lifetime risk of AF and increased longevity underscore the important public health burden posed by this arrhythmia worldwide. AF has multiple aetiologies and a broad variety of presentations. The primary pathologies underlying or promoting the occurrence of AF vary more than for any other cardiac arrhythmia, ranging from autonomic imbalance to organic heart disease and metabolic disorders, such as diabetes mellitus, metabolic syndrome, hyperthyroidism and kidney disease, and lifestyle factors such as smoking, alcohol consumption and participation in endurance sports. Biomarkers are increasingly being investigated and, together with clinical and genetic factors, will eventually lead to a clinically valuable detailed classification of AF which will also incorporate pathophysiological determinants and mechanisms of the arrhythmia. In turn, this will allow the development and application of precision medicine to this troublesome arrhythmia.

[PROCUREMENT OF SANITARY AND EPIDEMIOLOGICAL WELFARE IN THE REGION OF-CITY-RESORT SOCHI FOR DANGEROUS AND NATURAL-FOCI INFECTIOUS DIS- EASES IN 2015].

AIM: Analysis ofresults of epidemiologic monitoring especially dangerous, natural-foci and other infectious diseases, asill as epizootologic activity of natural foci of infection on,the terri- tory, of city-resort Sochi. MATERIALS AND METHODS: Laboratory studies of 820. samples by PCR; im- mune- and bacteriologic methods were carried out, among those 344 - clinical material, 12 - water from open bodies and 321 - field material. Molecular-genetic identification of-143 strains of Vibrio-cholerae, isolated from open water bodies of city-resort Sochi, was-carried out,. RESULTS: Circulation of causative agents of Q fever, tularemia and hemorrhagic fever with renal syndrome of Dobrava-Adler genotypes was established, -as well as rickettsia of tick spotted fever group Predomination of rotaviruses (70.9%) was detected during study of samples of clinical material in etiologic structure of sporadically emerging acute intestine infections. Relatively high temperature values of river water during summer months (from 18, to 30 C), exit of sulfide mineral waters into the riverbed, that create-alkaline medium, seasonal reduction of river debit and speed of water current facilitated sustenance of contamination of water of Agura river by V.cholerae. CONCLUSION: Activity of natural foci of the infectious disease and contamination of Agura iver by V.cholerae Ο1, (atoxigenic) gives evidence on the necessity of constant control of epidemiologic situation by dangerous and natural-foci infectious diseases on the territory of city-resort Sochi, as well as study regional features, of their causative agents, including using genetic methods.

Atrial fibrillation: the rate versus rhythm management controversy.

The fundamental management strategy for atrial fibrillation (AF) is still debated. There is no doubt that those patients at risk of thromboembolic events should be offered anticoagulant therapy. However, it is uncertain whether rhythm control (restoration and maintenance of sinus rhythm) or rate control (adjustment to a physiological ventricular rate while allowing AF to continue) is the preferred primary treatment option for the reduction of symptoms and major cardiovascular (CV) outcomes associated with AF. Several well conducted trials comparing the two strategies led to the conclusion that there was little to choose between them. However, guidelines leaned towards recommending rate control as the initial strategy, and reserved rhythm control for those who remained symptomatic. Recently this status quo is being increasingly challenged by the clear demonstration that left atrial catheter ablation is effective at suppressing AF resistant to traditional antiarrhythmic drugs, such as those that failed to demonstrate any superiority when compared with rate control. Also, recently introduced antiarrhythmic therapy may have superior efficacy with regard to reducing unexpected CV hospitalization, CV mortality and stroke. In addition, there is a growing perception that atrial remodelling should be best prevented by early rhythm control rather than delaying until rate control has proven unsatisfactory. For these reasons the results of large randomised clinical trials, which recruit patients soon after the presentation of AF and compare 'aggressive' modern rhythm control against the guideline approach of primary rate control, are eagerly awaited. In the meantime the pendulum of clinical opinion has begun to swing towards a rhythm control strategy.

Women's reproductive health needs in Russia: what can we learn from an intervention to improve post-abortion care?

It has been well documented that abortion is a common means of controlling fertility in Russia. Women undergo repeat abortions throughout their reproductive lives, but recent studies of abortion trends in the Russian Federation suggest that abortion rates are on the decline, use of modern contraceptives is increasing, and women dislike abortion as a method of fertility control. Using data collected during 1999-2003 in women's health facilities in three Russian cities, this paper reports the results of an evaluation of interventions to improve post-abortion care, which show an impressive increase in post-abortion contraceptive counselling but no reduction in the rate at which women present at clinics for repeat abortions. The findings indicate a discrepancy between women's stated preferences for modern medical contraceptive methods and their abortion-seeking behaviour. Further exploration of these data suggests that certain women resort to abortion with greater frequency than others, and points to the need for a more focused investigation of these women. These results indicate the complexities associated with changing what has been a relatively common and long-standing practice, and have implications for improving reproductive health services. Meeting the reproductive health needs of Russian women requires not only improved provider and client knowledge but may also demand a more focused delivery of client-centred care than may be the case in other settings.

Automatic ectopic beat elimination in short-term heart rate variability measurement.

Our studies deal with fully automatic measurement of heart rate variability (HRV) in short term electrocardiograms. Presently, all existing HRV analysis programs require user intervention for ectopic beat identification, especially of supraventricular ectopic beats (SVE). This makes the HRV measurement in large, e.g. epidemiological studies problematic. In this paper, we present a fully automatic algorithm for the discrimination of the ventricular (VE) and SVE ectopic beats from the normal QRS complexes suited for a reliable HRV analysis. The QRS identification is based on the template matching method. The ectopic beats are identified based on several morphological and timing properties of the electrocardiogram (ECG) signal. The method incorporates several approaches and makes HRV analysis of large numbers of electrocardiograms feasible. It uses the template matching for the basic morphology check of the QRS complex and the P-wave, the timing information to avoid unnecessary ectopic beat checks and to adjust thresholds and it also looks for a special QRS morphology, which is common in VEs. We used a testing set of 69 electrocardiograms selected from a large number of recordings. The selected ECGs contained abnormalities including ectopic beats, right branch bundle block, respiratory arrhythmia, blocked atrial extrasystole, high amplitude and wide T-waves. The evaluation of our method showed a specificity of 0.99, supraventricular ectopic beat sensitivity of 0.99 and ventricular ectopic beat sensitivity of 0.98.

Clinical relevance of silent atrial fibrillation: prevalence, prognosis, quality of life, and management.

Although first described about 100yr ago, atrial fibrillation (AF) is now recognized as the most common of all arrhythmias. It has a substantial morbidity and presents a considerable health care burden. Improved diagnosis and an ageing population with an increased likelihood of underlying cardiac disease results in AF in more than 1% of population. AF is associated with an approximately two-fold increase in mortality, largely due to stroke which occurs at an annual rate of 5-7%. Another risk to survival is heart failure, which is aggravated by poor control of the ventricular rate during AF. Usually AF is associated with a variety of symptoms: palpitations, dyspnea, chest discomfort, fatigue, dizziness, and syncope. Paroxysmal AF is likely to be symptomatic and frequently presents with specific symptoms, while permanent AF is usually associated with less specific symptoms. However, in at least one third of patients, no obvious symptoms or noticeable degradation of quality of life are observed. This asymptomatic, or silent, AF is diagnosed incidentally during routine physical examinations, pre-operative assessments or population surveys. Recently, a very large incidence of generally short paroxysms of AF has been seen in patients with implantable pacemakers or defibrillators and these arrhythmias are often silent. Pharmacological suppression of arrhythmia may be associated with a conversion from a symptomatic to an asymptomatic form of AF. Holter monitoring and transtelephonic monitoring studies have demonstrated that asymptomatic episodes of AF exceed symptomatic paroxysms by twelve-fold or more. Although symptoms may not stem directly from AF, the risk of complications is probably the same for symptomatic and asymptomatic patients. AF is found incidentally in about 25% of admissions for a stroke. Studies in patients with little or no awareness of their arrhythmia condition indicate that unrecognized and untreated AF may cause congestive heart failure. In patients with coronary bypass, AF may not only represent risk for immediate postoperative morbidity and increase hospital resource utilization, but being unrecognized, may produce a significant impact on long-term survival and quality of life. Although silent AF merits consideration for anticoagulation and rate control therapy according to standard criteria, whether antiarrhythmic therapy is relevant in this condition remains unclear.

Short-, mid-, and long-term reproducibility of the atrial signal-averaged electrocardiogram in healthy subjects: comparison with the conventional ventricular signal-averaged electrocardiogram.

Although atrial signal-averaged electrocardiogram (SAECG) has been proposed for noninvasive identification of patients with atrial tachyarrhythmias, the substantial variability of the measurement limits the clinical value. The aim of the study was to assess the short- to long-term reproducibility of atrial SAECG and to compare it to that of the conventional ventricular SAECG in 51 healthy volunteers (30 men; age 32 +/- 8 years). In each subject, SAECG recordings were obtained using MAC-VU electrocardiograph and HiRES and PHiRES software (Marquette Medical Systems) and repeated after 5 minutes, 1 day, 1 week, and 1 month. Automatically detected onset and offset of the filtered QRS complex and P wave were subsequently corrected by two independent observers, and the averaged values were used for the analysis. Conventional ventricular SAECG parameters: filtered QRS duration (QRStot), low amplitude signal duration, and root mean square voltage (RMS) of the terminal 40 ms of QRS, and 5 atrial parameters: filtered P wave duration (Ptot), RMS of the terminal 40, 30, 20 ms, and of the entire P wave were obtained. Relative errors of different pairs of measures were used to assess the intrasubject reproducibility. QRStot and Ptot were the most reproducible parameters. The relative errors after 5 minutes, 1 day, 1 week, and 1 month were 0.8% to 2.4% for QRStot, and 1.3% to 4.2% for Ptot. For RMS voltages, the relative errors exceeded 15% in short-term and 20% in long-term recordings. Although Ptot was statistically less reproducible than QRStot, the reproducibility of the former was good and comparable to that of the QRStot. The reproducibility of the voltage parameters was significantly poorer than that of the duration parameters. The study showed a satisfactory short- and long-term reproducibility of Ptot in the atrial SAECG in healthy subjects. However, low reproducibility of the voltage parameters should be considered in clinical applications.

Relation of ventricular repolarization to cardiac cycle length in normal subjects, hypertrophic cardiomyopathy, and patients with myocardial infarction.

BACKGROUND: Prolonged QT interval and QT dispersion have been reported to reflect an increased inhomogeneity of ventricular repolarization, which is believed to be responsible for the development of arrhythmic events in patients with long QT syndrome, coronary heart disease, and myocardial infarction, congestive heart failure, and hypertrophic cardiomyopathy (HC). HYPOTHESIS: This study was undertaken to determine whether an abnormal QT/RR dynamicity may reflect autonomic imbalance and may contribute to arrhythmogenesis in patients with heart disease. METHODS: The relation between QT, QTpeak (QTp), Tpeak-Tend (TpTe) intervals and cardiac cycle length was assessed in 70 normal subjects, 37 patients with HC, and 48 survivors of myocardial infarction (MI). A set of 10 consecutive electrocardiograms was evaluated automatically in each subject using QT Guard software (Marquette Medical Systems, Milwaukee, Wisc.). RESULTS: In patients with HC, all intervals were significantly prolonged compared with normals (p < 0.001 for QT and QTp; p < 0.04 for TpTc); in survivors of MI, this was true for the maximum QT and QTp intervals (p < 0.05). A strong linear correlation between QT, QTp, and RR intervals was observed in normals and in patients with MI and HC (r = 0.65-0.59, 0.82-0.77, 0.79-0.74, respectively, p < 0.0001). TpTe interval only showed a weak correlation with heart rate in normals (r = 0.24, p < 0.05) and was rate-independent in both patient groups (p = NS). Compared with normals, the slopes of QT/RR and QTp/RR regression lines were significantly steeper in patients with MI and HC (0.0990-0.0883, 0.1597-0.1551, 0.1653-0.1486, respectively). Regression lines were neither parallel nor identical between normals and patients (T > 1.96, Z > 3.07). There was no difference in steepness for TpTeR/RR lines between groups (0.0110, 0.0076, 0.0163, respectively). TpTe/QTp ratio was similar in normals and in patients with MI and HC (0.30 +/- 0.03, 0.31 +/- 0.07, 0.30 +/- 0.04, respectively), in the absence of any correlation between QTp and TpTe intervals, suggesting disproportional prolongation of both components of QT interval. CONCLUSION: Compared with normals, a progressive increase in QT and QTp intervals at slower heart rates in patients with MI and HC may indicate an enhanced variability of the early ventricular repolarization and may be one of the mechanisms of arrhythmogenesis.

QT interval and QT dispersion measured with the threshold method depend on threshold level.

Various computerized methods with multiple parameter options for measurements of the QT interval now are available. The optimum parameter setting for most algorithms is not known. This study evaluated the influence of the threshold level applied on the T wave differential on the QT interval and its dispersion measured in normal and abnormal electrocardiograms (ECGs). Seven hundred sixty ECGs recorded in 76 normal subjects and 630 in 63 patients with hypertrophic cardiomyopathy (HCM) (10 consecutive recordings in each individual) were analyzed. In each lead of each ECG, the QT interval was measured by the threshold method applied to the first differential of the T wave. The threshold level was varied between 5% and 30% of the T wave maximum in 1% steps, resulting in 26 different choices of QT measurements. With each choice the maximum QTc and the QT dispersion (QTd, standard deviation of the QT in all 12 leads) were obtained for each recording. The maximum QTc was significantly longer in HCM patients than in normal subjects (P < 0.001) at all threshold levels except between 5% and 7%. The QTd was significantly greater in HCM patients at all threshold levels. The QTc and QTd changed significantly with the threshold level. The maximum QTc varied up to 60 ms in normal subjects and up to 70 ms in HCM patients, depending on the threshold level. Thus, the QT interval and its dispersion measured with the threshold method applied to the first T wave differential depended significantly on the threshold level in both normal and diseased hearts. All programmable options of available automatic instruments should be examined carefully before any study, and all algorithmic details should by systematically presented.

Comparative reproducibility of QT, QT peak, and T peak-T end intervals and dispersion in normal subjects, patients with myocardial infarction, and patients with hypertrophic cardiomyopathy.

Abnormal repolarization is associated with arrhythmogenesis. Because of controversies in existing methodology, new computerized methods may provide more reliable tools for the noninvasive assessment of myocardial repolarization from the surface electrocardiogram (ECG). Measurement of the interval between the peak and the end of the T wave (TpTe interval) has been suggested for the detection of repolarization abnormalities, but its clinical value has not been fully studied. The intrasubject reproducibility and reliability of automatic measurements of QT, QT peak, and TpTe interval and dispersion were assessed in 70 normal subjects, 49 patients with acute myocardial infarction (5th day; MI), and 37 patients with hypertrophic cardiomyopathy (HC). Measurements were performed automatically in a set of 10 ECGs obtained from each subject using a commercial software package (Marquette Medical Systems, Milwaukee, WI, U.S.A.). Compared to normal subjects, all intervals were significantly longer in HC patients (P < 0.001 for QT and QTp; p < 0.05 for TpTe); in MI patients, this difference was only significant for the maximum QT and QTp intervals (P < 0.05). In both patient groups, the QT and QTp dispersion was significantly greater compared to normal subjects (P < 0.05) but no consistent difference was observed in the TpTe dispersion among all three groups. In all subjects, the reproducibility of automatic measurement of QT and QTp intervals was high (coefficient of variation, CV, 1%-2%) and slightly lower for that of TpTe interval (2%-5%; p < 0.05). The reproducibility of QT, QTp, and TpTe dispersion was lower (12%-24%, 18%-28%, 16%-23% in normal subjects, MI and HC patients, respectively). The reliability of automatic measurement of QT, QTp, and TpTe intervals is high but the reproducibility of the repeated measurements of QT, QTp and TpTe dispersion is comparatively low.

Agreement and reproducibility of automatic versus manual measurement of QT interval and QT dispersion.

To determine whether the automatic measurement of the QT interval is consistent with the manual measurement, this study evaluated the reproducibility and agreement of both methods in 70 normal subjects and 54 patients with hypertrophic cardiomyopathy. The mean, minimum, and maximum QT interval and QT dispersion were computed in a set of 6 consecutive electrocardiograms (3 in the supine and 3 in the standing position) obtained from each subject. The automatic method determined the T-wave end as the intersect of the least-squares-fit line around the tangent to the T-wave downslope with the isoelectric baseline. Manual measurements were obtained using a high-resolution digitizing board. QT dispersion was defined as the difference between the maximum and minimum QT interval and as standard deviations of the QT interval duration in all and precordial leads. In patients with hypertrophic cardiomyopathy, the absolute values of the QT interval and QT dispersion were significantly higher than those in normal subjects (p < 0.0001). In both groups, the intrasubject variability of the QT interval was significantly lower with automatic than with manual measurement (p < 0.05). The agreement between automatic and manual QT interval measurements was surprisingly poor, but it was better in patients with hypertrophic cardiomyopathy (r2 = 0.46 to 0.67) than in normal subjects (r2 = 0.10 to 0.25). In both groups, the reproducibility and agreement of both methods for QT dispersion were significantly poorer than for QT interval. Hence, the automatic QT interval measurements are more stable and reproducible than manual measurement, but the lack of agreement between manual and automatic measurement suggests that clinical experience gained with manual assessment cannot be applied blindly to data obtained from the automatic systems.