Recognition of Supraventricular Arrhythmias in Holter ECG Recordings by ECHOView Color Map: A Case Series Study.

Ambulatory 24-72 h Holter ECG monitoring is recommended for patients with suspected arrhythmias, which are often transitory and might remain unseen in resting standard 12-lead ECG. Holter manufacturers provide software diagnostic tools to assist clinicians in evaluating these large amounts of data. Nevertheless, the identification of short arrhythmia events and differentiation of the arrhythmia type might be a problem in limited Holter ECG leads. This observational clinical study aims to explore a novel and weakly investigated ECG modality integrated into a commercial diagnostic tool ECHOView (medilog DARWIN 2, Schiller AG, Switzerland), while used for the interpretation of long-term Holter-ECG records by a cardiologist. The ECHOView transformation maps the beat waveform amplitude to a color-coded bar. One ECHOView page integrates stacked color bars of about 1740 sequential beats aligned by R-peak in a window (R ± 750 ms). The collected 3-lead Holter ECG recordings from 86 patients had a valid duration of 21 h 20 min (19 h 30 min-22 h 45 min), median (quartile range). The ECG rhythm was reviewed with 3491 (3192-3723) standard-grid ECG pages and a substantially few number of 51 (44-59) ECHOView pages that validated the ECHOView compression ratio of 67 (59-74) times. Comments on the ECG rhythm and ECHOView characteristic patterns are provided for 14 examples representative of the most common rhythm disorders seen in our population, including supraventricular arrhythmias (supraventricular extrasystoles, paroxysmal supraventricular arrhythmia, sinus tachycardia, supraventricular tachycardia, atrial fibrillation, and flutter) and ventricular arrhythmias (ventricular extrasystoles, non-sustained ventricular tachycardia). In summary, the ECHOView color map transforms the ECG modality into a novel diagnostic image of the patient's rhythm that is comprehensively interpreted by a cardiologist. ECHOView has the potential to facilitate the manual overview of Holter ECG recordings, to visually identify short-term arrhythmia episodes, and to refine the diagnosis, especially in high-rate arrhythmias.

Application of Dense Neural Networks for Detection of Atrial Fibrillation and Ranking of Augmented ECG Feature Set.

Considering the significant burden to patients and healthcare systems globally related to atrial fibrillation (AF) complications, the early AF diagnosis is of crucial importance. In the view of prominent perspectives for fast and accurate point-of-care arrhythmia detection, our study optimizes an artificial neural network (NN) classifier and ranks the importance of enhanced 137 diagnostic ECG features computed from time and frequency ECG signal representations of short single-lead strips available in 2017 Physionet/CinC Challenge database. Based on hyperparameters' grid search of densely connected NN layers, we derive the optimal topology with three layers and 128, 32, 4 neurons per layer (DenseNet-3@128-32-4), which presents maximal F1-scores for classification of Normal rhythms (0.883, 5076 strips), AF (0.825, 758 strips), Other rhythms (0.705, 2415 strips), Noise (0.618, 279 strips) and total F1 relevant to the CinC Challenge of 0.804, derived by five-fold cross-validation. DenseNet-3@128-32-4 performs equally well with 137 to 32 features and presents tolerable reduction by about 0.03 to 0.06 points for limited input sets, including 8 and 16 features, respectively. The feature reduction is linked to effective application of a comprehensive method for computation of the feature map importance based on the weights of the activated neurons through the total path from input to specific output in DenseNet. The detailed analysis of 20 top-ranked ECG features with greatest importance to the detection of each rhythm and overall of all rhythms reveals DenseNet decision-making process, noticeably corresponding to the cardiologists' diagnostic point of view.

Are Three Weeks of Oral Anticoagulation Sufficient for Safe Cardioversion in Atrial Fibrillation?

Background and Objectives: Patients with atrial fibrillation (AF), lasting >48 h, considered for cardioversion, are recommended ≥3 weeks of oral anticoagulation before sinus rhythm restoration because of high risk of development of left atrial thrombosis (LAT) and stroke. However, the optimal duration of anticoagulation in the presence of overt LAT is unknown. Materials and Methods: An open-label study aimed to investigate the prevalence of spontaneous echo contrast (SEC) and LAT before and after 3 weeks of direct oral anticoagulant (DOAC) treatment. We included 51 consecutive patients (50.9% males), mean age 69.3 ± 7.4 years with paroxysmal/unknown duration of AF, considered for cardioversion, who agreed to have transesophageal echocardiography at enrollment and 3 weeks later. Results: At baseline SEC was present in 26 (50.9%) and LAT in 10 (19.6%) of 51 patients. After 3 weeks on DOAC, SEC persisted in 12 (25.0%) and LAT in 7 (14.5%) of 48 patients, p < 0.05 vs. baseline. Factors, associated most strongly with persistence of SEC/LAT, were left atrial appendage (LAA) emptying velocity <20 cm/s (OR = 2.82), LAA lobes >2 (OR = 1.84), and indexed left atrial volume ≥34 mL/m2 (OR = 1.37). Conclusions: In our study the incidence of SEC/LAT, particularly in AF with unknown duration, was not as low as we expected. The prevalence of SEC/LAT seemed to be dependent on factors not routinely evaluated in AF patients planned for cardioversion (indexed LA volume, LAA morphology and number of lobules, LAA emptying velocity, etc.). Our data suggested an individualized approach for DOAC duration in AF patients before an attempt for restoration of sinus rhythm is made, taking into consideration the LAA morphology and function.

Physicians' Perceptions of Their Patients' Attitude and Knowledge of Long-Term Oral Anticoagulant Therapy in Bulgaria.

Background and Objectives: Oral anticoagulation (OAC) is widely used in daily clinical practice worldwide for various indications. We aimed to explore the perception of Bulgarian clinicians about their patients' attitude and knowledge of long-term OAC, prescribed for atrial fibrillation (AF) and/or known deep venous thrombosis (DVT)/pulmonary embolism (PE). Materials and Methods: We performed a cross-sectional study that involved 226 specialists: 187 (82.7%) cardiologists, 23 (10.2%) neurologists, and 16 (7.1%) vascular surgeons. They filled in a questionnaire, specially designed for our study, answering various questions regarding OAC treatment in their daily clinical practice. Results: The mean prescription rate of OACs in AF patients was 80.3% and in DVT/PE-88.6%. One hundred and eighty-seven (82.7%) of the participants stated they see their patients on OAC at least once per month. According to more than one-third of the inquired clinicians, the patients did not understand well enough the provided information concerning net clinical benefit of OAC treatment. About 68% of the clinicians declared that their patients would prefer a "mutual" approach, discussing with the physician the OAC options and taking together the final decision, whereas according to 43 (19.0%), the patients preferred the physician to take a decision for them. Patients' OAC treatment had been interrupted at least once within the last year due to a physician's decision by 178 (78.8%) of the participants and the most common reason was elective surgery. The most influential factors for a patient's choice of OAC were the need of a specific diet to be kept, intake frequency, and possible adverse reactions. Conclusions: Our results suggest that a clinician's continuous medical education, shared decision-making, and appropriate local strategies for improved awareness of AF/DVT/PE patients are key factors for improvement of OAC management.

Risk Factors, Co-Morbidities and Treatment of In-Hospital Patients with Atrial Fibrillation in Bulgaria.

BACKGROUND AND OBJECTIVES: Atrial fibrillation (AF) is the most common arrhythmia worldwide and a major risk factor for cardiovascular complications. Our study aimed to investigate the prevalence, risk factors, demographics, co-morbidities and treatment of AF among in-hospital Bulgarian patients. MATERIALS AND METHODS: A cross-sectional study including 1027 consecutive patients (n = 516, 50.2% males) with a mean age of 67.6 ± 11.3 years, hospitalized for any reason from 1 May until 31 December 2016 in one of the largest internal clinics in Bulgaria, was carried out. RESULTS: Atrial fibrillation was diagnosed in 634 (61.7%) patients. The prevalence of modifiable AF risk factors was as follows: heart failure, 98.9%; arterial hypertension (HTN), 93.5%; valvular heart disease, 40.9%; chronic lung disease, 26.7%; type 2 diabetes mellitus, 24.9%; thyroid disease, 16.9%; and ischemic heart disease, 11.2%. Univariate logistic regression analysis identified the following risk factors with strongest impact on AF: left ventricular ejection fraction <40% (odds ratio (OR) = 1.951, 95% confidence interval (CI) 1.208⁻3.151), valvular heart disease (OR = 1.926, 95% CI 1.134⁻3.862), left ventricular ejection fraction 40⁻49% (OR = 1.743, 95% CI 1.248⁻3.017), HTN (OR = 1.653, 95% CI 1.092⁻3.458). History of ischemic stroke was present in 14.4% of the patients with AF. Oral antithrombotic drugs were prescribed to 85.7%: direct oral anticoagulants to 37.9%, vitamin K antagonists to 43.2%, and antiplatelets to 4.6%. Heart rate control medications and antiarrhythmics were prescribed to 75.4% and 40.2%, respectively. CONCLUSIONS: Atrial fibrillation was highly prevalent among our study population. Reduced and mid-range left ventricular ejection fraction, valvular heart disease, and HTN were the risk factors with the strongest association with AF. Although a large number of our AF patients were administered antithrombotic treatment, the prescription rate of oral anticoagulants should be further improved.

Pericardial Effusion in Obstructive Sleep Apnea without Pulmonary Arterial Hypertension and Daily Hypoxemia - is it Unusual?

Background: Pericardial effusion in chronic hypoxemic lung diseases, such as Obstructive Sleep Apnea syndrome, usually occurs after the development of severe pulmonary arterial hypertension. However, data about the frequency of pericardial effusions in Obstructive Sleep Apnea syndrome without pulmonary arterial hypertension and/or daytime hypoxemia are still scarce, and their pathogenesis is unclear. Aims: To assess the prevalence of pericardial effusions and their volume and location in patients with obesity and Obstructive Sleep Apnea syndrome without pulmonary arterial hypertension and/or hypoxemia. Study Design: Cross-sectional study. Methods: We included 279 consecutive patients (162 males) with newly diagnosed Obstructive Sleep Apnea syndrome having a mean age of 42.8±12.4 years and a mean body mass index of 37.3±7.8 kg/m2. Obstructive Sleep Apnea syndrome was confirmed by polysomnography. Main exclusion criteria were concomitant inflammatory diseases, thyroid dysfunction, daytime hypoxemia, nephrotic syndrome, left ventricular systolic dysfunction and pulmonary arterial hypertension. Results: Pericardial effusion was found in 102 (36.56%) -all of them with moderate to severe obstructive Sleep Apnea syndrome. The mean effusion volume was mild to moderate (up to 250 mL). In 36 patients (35.3%) the pericardial effusion was diffuse, in 42 (41.2%), the pericardial effusion was located in front of the right atrium and the right ventricle, and in 24 (23.5%) the pericardial effusion was situated in front of the right cardiac cavities and the left atrium. We found a significant positive correlation between the presence of pericardial effusion and apnea-hypopnea index (r=0.374, p<0.001), body mass index (r=0.473, p<0.001), and desaturation time during sleep (r=0.289, p<0.001). Conclusion: Pericardial effusion in patients with obesity and moderate to severe Obstructive Sleep Apnea syndrome without daily hypoxemia and/or pulmonary hypertension is a relatively common finding. The occurrence of pericardial effusions is dependent mostly on the grade of Obstructive Sleep Apnea syndrome, degree of obesity, and duration of sleep desaturation.

EFFICACY AND SAFETY OF A SINGLE-PILL COMBINATION OF ATORVASTATIN/AMLODIPINE IN PATIENTS WITH ARTERIAL HYPERTENSION AND DYSLIPIDEMIA.

- The aim was to evaluate the efficacy of a single-pill combination of atorvastatin/amlodipine in patients with arterial hypertension, dyslipidemia and moderate to high cardiovascular risk. This prospective study included 243 patients with arterial hypertension, dyslipidemia and moderate to high cardiovascular risk, mean age 63.3±9.8 years. All patients were prescribed a treatment with one of the following doses of a single-pill combination of atorvastatin/amlodipine: 10/5, 10/10, 20/5 or 20/10 mg daily. The follow-up period was 3 months. The mean baseline values of the systolic and diastolic blood pressure were 155.7±16.2 and 92.0±9.2 mm Hg, respectively. At month 3, the respective mean systolic and diastolic blood pressure values were 136.9±26.9 and 80.6±5.1 mm Hg. The mean baseline values of total cholesterol and low-density lipoprotein cholesterol were 6.6±1.2 and 4.4±1.1 mmol/L, respectively. At month 3, the respective mean values of total cholesterol and low-density lipoprotein cholesterol were 5.1±0.9 and 2.9±1.0 mmol/L. Treatment was discontinued in 9 (3.7%) patients due to adverse events. In conclusion, treatment with the single-pill combination of atorvastatin/amlodipine was effective and well tolerated by the patients with arterial hypertension, dyslipidemia and moderate to high cardiovascular risk.

Effects of aliskiren on blood pressure and myocardial function assessed by global longitudinal strain in patients with arterial hypertension and diastolic dysfunction.

OBJECTIVE: To evaluate the effects of aliskiren on blood pressure and myocardial function assessed by global longitudinal strain in patients with uncontrolled arterial hypertension. PATIENTS AND METHODS: Forty-five patients were included in the study (29 males, 16 females, mean age 58.7 +/- 12.4 years) with BP > 140/90 mmHg despite treatment with combined antihypertensive therapy and echocardiographic data for diastolic dysfunction: E/E'ratio < or = 8, E/A ratio < 0.8, deceleration time (DT) > 200 msec. Aliskiren (2 x 150 mg per day) was added to the previous therapy. The follow-up period was 1 year, including monthly clinical visits. Echocardiographic assessment of the left ventricular function by longitudinal strain and Doppler analysis of the trans-mitral blood flow was performed at months 1, 6, 12. RESULTS: The baseline systolic and diastolic blood pressures scores were 153.4 +/- 14.4/99.2 +/- 6.7 mmHg and 157.6 +/- 12.5/97.3 +/- 8.2 mmHg for males and females, respectively. The systolic and diastolic values at 1 month were 131.7 +/- 7.4/83.6 +/- 5.2 mmHg for males and 132.4 +/- 5.3/81.8 +/- 6.9 mmHg for females (p < 0.05 vs. baseline). The baseline E/E' was 6.5 +/- 0.9, E/A - 0.6 +/- 001, DT - 258 +/- 32.7 msec. These indicators at month 12 were as follows: E/E' - 7.0 +/- 0.64, E/A - 0.7 +/- 0.05, DT - 239 +/- 16.5 msec, p = NS. Baseline global longitudinal strain in males was -10.4 +/- 0.7% and -11.0 +/- 0.9% in females and at month 12 - 16.3 +/- 0.9% and -17.5 +/- 0.7% for males and females, respectively, p < 0.05. For the period of follow-up no adverse effects due to aliskiren treatment were registered. CONCLUSIONS: Adding aliskiren to combined antihypertensive therapy leads to significant improvement of hypertension control and myocardial function assessed by global longitudinal strain.

Possibilities of signal-averaged orthogonal and vector electrocardiography for locating and size evaluation of acute myocardial infarction with ST-elevation.

OBJECTIVE: The signal-averaged electrocardiography (SAECG) is known to be a useful tool for extraction and analysis of low-amplitude signal components. We found SAECG may be useful for precise location of the site of the myocardial necrosis and assessment of the severity of impaired left ventricular systolic function of patients with ST-elevation myocardial infarct (STEMI) in the acute phase. METHODS: High-resolution (1 MHz) ECG from 3 groups were collected: healthy controls (20), patients with anterior (17) and inferior STEMI (21). The three orthogonal leads X, Y, Z were synthesized from the 12 standard leads by known transformation. Synchronized averaging was carried out over hundred P-QRS-T intervals of each orthogonal lead. The resulting intervals of all subjects within a group were additionally averaged. The obtained X, Y and Z patterns, as well as the derived loops in the vectorcardiographic planes (VCG patterns) were studied for significant divergences. RESULTS: The summarized analysis presenting the possibilities of QRS- and T-vector indicators for correct classification of patients with STEMI shows that the determined discriminators classify correctly 91.4% of the examined patients. The optimized set of QRS-vector indicators for discrimination between healthy controls and patients with inferior STEMI include angle alpha of the maximal vector in both the sagittal and the horizontal plane. These two indicators show as high predictive value as all QRS-vector indicators -82.9%. The optimized combination of QRS-vector indicators for discrimination between healthy controls and patients with anterior STEMI includes amplitude of the maximal vector in the frontal and sagittal planes, angle alpha of the maximal vector in the sagittal plane and the area of the loop in the frontal plane. This optimized combination has a common mean percentage of correctly classified patients of about 91.9%. The accuracy for infarct zone localization is improved with optimized combinations involving together QRS- and T-vector indicators. The achieved common mean percentages of correct classifications are 94.6% (healthy controls-anterior STEMI), 92.7% (healthy controls-inferior STEMI) and 97.4% (anterior STEMI-inferior STEMI). The set of all QRS-and T-vector indicators of patients with anterior STEMI regarding 2D-echocardiographic ejection fraction shows very high correlation coefficient, reaching about 0.99. In contrast, we did not find significantly high correlation in patients with inferior STEMI. CONCLUSIONS: Both the signal-averaged orthogonal ECG and the synthesized on its basis VCG show markedly high sensitivity regarding location of ST-elevation myocardial infarct. The possibility for facilitated and fast performance of this examination in clinical conditions, including emergency, the lack of necessity of specially trained staff for carrying out the examination and interpretation of the results, as well as the very low prime cost, make this electrophysiological method very suitable for application in the routine clinical practice for qualitative and quantitative assessment of patients with acute coronary syndromes.

Dataset of manually measured QT intervals in the electrocardiogram.

BACKGROUND: The QT interval and the QT dispersion are currently a subject of considerable interest. Cardiac repolarization delay is known to favor the development of arrhythmias. The QT dispersion, defined as the difference between the longest and the shortest QT intervals or as the standard deviation of the QT duration in the 12-lead ECG is assumed to be reliable predictor of cardiovascular mortality. The seventh annual PhysioNet/Computers in Cardiology Challenge, 2006 addresses a question of high clinical interest: Can the QT interval be measured by fully automated methods with accuracy acceptable for clinical evaluations? METHOD: The PTB Diagnostic ECG Database was given to 4 cardiologists and 1 biomedical engineer for manual marking of QRS onsets and T-wave ends in 458 recordings. Each recording consisted of one selected beat in lead II, chosen visually to have minimum baseline shift, noise, and artifact.In cases where no T wave could be observed or its amplitude was very small, the referees were instructed to mark a 'group-T-wave end' taking into consideration leads with better manifested T wave.A modified Delphi approach was used, which included up to three rounds of measurements to obtain results closer to the median. RESULTS: A total amount of 2*5*548 Q-onsets and T-wave ends were manually marked during round 1. To obtain closer to the median results, 8.58 % of Q-onsets and 3.21 % of the T-wave ends had to be reviewed during round 2, and 1.50 % Q-onsets and 1.17 % T-wave ends in round 3. The mean and standard deviation of the differences between the values of the referees and the median after round 3 were 2.43 +/- 0.96 ms for the Q-onset, and 7.43 +/- 3.44 ms for the T-wave end. CONCLUSION: A fully accessible, on the Internet, dataset of manually measured Q-onsets and T-wave ends was created and presented in additional file: 1 (Table 4) with this article. Thus, an available standard can be used for the development of automated methods for the detection of Q-onsets, T-wave ends and for QT interval measurements.