An approach to 24-hour electrocardiogram monitoring in sheep experimental model

Sheep could be an excellent research subject for large animal experimental studies because of their heart structure and physiology have a lot similarity to the human. Long term ECG monitoring is a convenient tool for human and possibly veterinary clinical practice and research. Continuous ECG recording can be used to monitor and evaluate body physiological responses in various experimental conditions. Experience on sheep ECG monitoring techniques is sparse and mostly focused on short term ECG recordings. We developed a peculiar technique of 24-hour sheep ECG monitoring based on the available data on large mammal model, where we tried to share some insights and practical solutions working with this type of animals for ECG monitoring by using several commercially available ECG monitors also used for the human practice. Some producer specific hardware and software characteristic that we found important in daily practice were also discussed. In conclusion, sheep as big animal is relatively good object for Holter monitoring experimental studies: ECG monitoring is easily affordable, registered ECG signal is of similar quality as in human clinical practice, which is sufficient for the heart rhythm monitoring and arrhythmia and conduction disorder diagnostics. Additional effort might be needed for 24-hour heart rate variability calculations because manual revision of software ECG signal interpretations is requiring, but short-term calculations can be made easy

Impact of the radiofrequency ablation on the intrinsic autonomic innervation of the heart

[...]. Aim of the study. The purpose of the study was the evaluation the functional and structural changes undergoing in the cardiac intrinsic ANS of the sheep after the RFA of cardiac ganglionated plexuses of the left atrium during the 12-month follow-up. Study goals:1. Evaluation of basic HRV time (Heart rate, SDNN, RMSSD, pNN50, HRV TI) and frequency (HF, LF, VLF, LF/HF) domain parameter values for the sheep. 2. Perform the epicardial radiofrequency ablation in the LA at the PV roots of the sheep heart. 3. Evaluation of the cardiac intrinsic nervous system functional changes immediately after the procedure (2-3 days) and during the 12-month follow-up. 4. Evaluation of the structural changes of the cardiac intrisic ANS after the RFA in sheep heart. [...]

Atrial Pacing Affects Left Atrial Morphological and Functional Parameters Early after Pacemaker Implantation

Background and Objectives: Chronic atrial stimulation might impair left atrial (LA) function. We aimed to assess the impact of atrial pacing burden on LA volumetric and functional parameters after implantation of a dual-chamber pacemaker. Materials and Methods: The prospective study included 121 subjects with sinus node disease (SND) or atrioventricular block (AVB) that received a dual-chamber pacemaker. After device implantation, the subjects were divided into three groups: (1) SND with a lower rate (LR) set to 60 bpm and rate response enabled; (2) AVB with an LR set to 60 bpm and no rate response; and (3) AVB with an LR set to 40 bpm and no rate response. Subjects were followed at one and three months. Two subsets of patients with high and low atrial pacing burdens accompanied by low ventricular pacing percentage were analyzed. LA function was evaluated with volumetric and strain parameters from transthoracic echocardiography. Results: The high atrial low ventricular pacing group consisted of 38 subjects, and the low atrial low ventricular group consisted of 22 subjects. When looking at the change in volumetric parameters, we observed a tendency for volumes to increase in both groups; however, only minimal LA volume reached statistical significance at three months in the high atrial pacing group. A trend towards the lowering of an active emptying fraction at one month (p = 0.076) became significant at three months (p = 0.043), and was also only observed in the same group. Moreover, a decrease in the tendency to reach statistical significance at three months for reservoir and contractile strain parameters and stiffness index was only observed in the high atrial pacing group. Meanwhile, in the low atrial pacing burden group, all parameters remained significantly unchanged. Conclusions: The burden of right atrial pacing in patients with preserved left ventricular function negatively influences functional and morphologic LA parameters. Moreover, negative effects take place soon after pacemaker implantation and appear to be sustained

Evaluation of atrial fibrillation management and cardiovascular risk profile in atrial fibrillation patients: A cross-sectional survey

Objective The aim of this study to investigate the most frequent risk factors of atrial fibrillation (AF), co-morbidities, complications associated with AF and the use of anticoagulants and other medications in patients who were referred to university hospitals in Lithuania. Materials and methods This cross-sectional study enrolled consecutive inpatients and outpatients with AF presenting to cardiologists in the two biggest Lithuanian university hospitals from November 2013 to May 2014. AF diagnosis was confirmed by a 12-lead ECG or 24-h Holter with an episode duration of >30 s. Results A total number of 575 patients were recruited, and complete data on clinical subtype were available for 515 patients (mean age of 70.7 years; 48.5% of women). Permanent AF was the most frequent type of AF (46.6%). Common comorbidities were hypertension (85.8%), heart failure (77.9%) and coronary artery disease (51.8%). Amiodarone was the most common antiarrhythmic agent used in 14.6% of the patients, while beta-blockers and digoxin were the most often used rate control drugs (59.6% and 10.7%, respectively). Oral anticoagulants were used by 53.3% of the patients; of them, 95.6% used vitamin K antagonists, while non-vitamin K antagonist were used by only 4.4%. The INR within a therapeutic range (2.0–3.0) was documented in 19.2% of the patients. Other antithrombotic drugs such as aspirin and clopidogrel were used in 13.7% and 2.0% of the patients, respectively; dual antiplatelet treatment was administered in 6.2% of the patients. Of the entire cohort, the mean CHA2DS2-VASc score was 3.97 ± 1.6 and the mean HAS-BLED score was 2.25 ± 1.0. Conclusions Compliance with the treatment guidelines remains suboptimal and further patient education is needed