Atrial Wave Research Articles

Mechanical wave velocities in acute myocardial infarction: an exploratory study using three-dimensional high frame rate echocardiography

Abstract Background Evaluation of cardiac function is crucial for management of patients with acute myocardial infarction (AMI). Recently, high frame rate (HFR) echocardiography has enabled identification of fast-propagating mechanical waves (MW) within the myocardium. These waves have the potential to offer unique insights into myocardial tissue properties, including edema and fibrosis. However, the potential of 3D HFR echocardiography to accurately quantify MW velocities and thereby assess myocardial stiffness in AMI patients remains unexplored. Purpose To assess the feasibility of a novel method for estimating MW velocities using 3D HFR echocardiography in patients with AMI compared to healthy controls. Methods Twenty patients with first time ST-elevation myocardial infarction were included within 48 hours after reperfusion therapy. We used a commercially available ultrasound scanner to acquire conventional 3D high-quality (~20 frames per second) acquisitions and subsequent 3D HFR recordings (~820 frames per second). The high-quality recording was used to extract a myocardial mask to define the region of interest in the HFR acquisition to detect the atrial kick wave and generate a comprehensive 3D map of MW propagation and velocities. We compared MW velocities between these patients and twenty age- and sex-matched healthy controls. Results MW velocities were successfully measured in 93% of participants (17 patients and 20 controls). Global MW velocities were significantly higher in AMI patients compared to healthy controls (2.1±0.6m/s vs. 1.5±0.2m/s, p<0.001). Territorial values, corresponding to the theoretical perfusion area of the three main coronary arteries, were significantly higher in infarct-related territories in patients when compared to same territories in controls for all coronary territories: Right coronary artery: 1.9±0.7 m/s vs. 1.4±0.3m/s, p<0.05; Circumflex artery: 3.1±1.5m/s vs. 1.7±0.4m/s, p<0.01; and Left anterior descending artery: 1.8±0.5m/s vs. 1.4±0.2m/s, p<0.01. Conclusions Estimation of MW velocities using a novel 3D HFR echocardiography method was feasible in most patients with AMI and all healthy controls. MW velocities were higher in patients compared to healthy controls and infarcted compared to non-infarcted coronary territories. These findings confirm the potential of non-invasive myocardial tissue characterization by MW imaging.Boxplot of MW velocities3D HFR MW visualisation

Atypical Presentation of Pre-excited Atrial Fibrillation in an Elderly Patient: A Case Report

Pre-excited atrial fibrillation (AF) is a significant clinical condition associated with Wolff-Parkinson-White (WPW) syndrome, characterized by an accessory pathway that enables rapid conduction of atrial fibrillatory waves to the ventricles, leading to dangerously elevated ventricular rates. While WPW syndrome is typically diagnosed in younger individuals, its occurrence in elderly patients is rare and often underreported. This case report discusses a 79-year-old male with well-controlled hypertension who was admitted for poorly tolerated irregular tachycardia with broad QRS complexes, indicative of pre-excited atrial fibrillation (AF). Urgent synchronized electrical cardioversion successfully restored sinus rhythm. Although catheter ablation was proposed as a definitive treatment, the patient chose to postpone the procedure, with close monitoring implemented afterward. This case underscores the challenges of diagnosing WPW syndrome in elderly patients, the potential dangers of pre-excited AF, and the importance of individualized management strategies tailored to patient preferences and comorbidities.

The feasibility of atrial Fibrillatory wave amplitude in predicting ablation outcomes in persistent atrial fibrillation

BackgroundAtrial fibrosis has a significant impact on the success rate of catheter ablation (CA) treatment of atrial fibrillation (AF). The fibrotic tissues could be reflected by the amplitude of the fibrillatory wave (F-wave). Methods and Results704 patients with persistent AF and at least 1-year follow-up after CA were included as the internal group. 101 patients from another hospital were used as the external validation cohort. A 12‑lead ECG was performed before CA and the maximum FWA in three ECG leads (aVL, aVF, V1) were measured. The FWA score (0 to 6 points according to the amplitude range of the three leads) of each patients was calculated. Five models including clinical features, FWA score, CHA2DS2-VASc score, APPLE score and the fusion of clinical features and FWA score were built. The FWA score was superior to the model constructed by clinical variables, CHA2DS2-VASc score and APPLE score. It not only had good predictive performance for AF recurrence, with an AUC value of 0.812 (95% CI 0.724–0.900), but also showed a significant predictive value for the recurrence rate according to F-wave amplitude. In the external validation cohort, the FWA score showed similar results (AUC 0.768, 95% CI 0.672–0.865). ConclusionsThe present study reveals the significant predictive value of the FWA score for persistent AF ablation recurrence.

The Relation of Ductus Venosus Pulsatility Index and Nuchal Translucency Thickness in a First-Trimester Sonographic Examination: A Matched Case-Control Study

Objective: Accumulating evidence suggests that abnormal ductus venosus (DV) flow is associated with fetal anomalies. This study aimed to investigate the relationship between quantitative DV Doppler parameters and nuchal translucency (NT). Materials and Methods: A total of 76 singleton pregnancies with an NT ≥3 mm were enrolled in the experimental group, and 156 singleton pregnancies with an NT <3 mm were recruited in the control group. Ductus venosus Doppler parameters were collected for both groups. The relationship of the DV Doppler parameters between the two groups and the correlation within the experimental group were analyzed. A receiver-operating characteristic curve was used to determine the best diagnostic cut-off point of DV pulsatility index (DVPI) to indicate a measured NT ≥3 mm. Results: There was a significantly higher values for DVPI, DV resistance index (DVRI), and systolic velocity/maximum velocity during atrial wave ratio in fetuses with an NT ≥3 mm compared with those in the control group ( P < .00). Fetuses with increased NT, DVPI, and DVRI showed significant positive correlations with NT ( P < .00; r = 0.44 and P < .00; r = 0.37, respectively). The best diagnostic cut-off point of DVPI for indicating a measured NT ≥3 mm was 1.15, indicating acceptable performance for the area under the curve of 0.83 (95% confidence interval: 0.770–0.892). Conclusion: In this study, in fetuses with an NT ≥3, the DVPI was higher than that in those with an NT <3. In addition, a positive correlation between DVPI and an NT ≥3 was observed.

The frequency of atrial fibrillatory waves is modulated by the spatiotemporal pattern of acetylcholine release: a 3D computational study.

In atrial fibrillation (AF), the ECG P-wave, which represents atrial depolarization, is replaced with chaotic and irregular fibrillation waves (f waves). The f-wave frequency, F f, shows significant variations over time. Cardiorespiratory interactions regulated by the autonomic nervous system have been suggested to play a role in such variations. We conducted a simulation study to test whether the spatiotemporal release pattern of the parasympathetic neurotransmitter acetylcholine (ACh) modulates the frequency of atrial reentrant circuits. Understanding parasympathetic involvement in AF may guide more effective treatment approaches and could help to design autonomic markers alternative to heart rate variability (HRV), which is not available in AF patients. 2D tissue and 3D whole-atria models of human atrial electrophysiology in persistent AF were built. Different ACh release percentages (8% and 30%) and spatial ACh release patterns, including spatially random release and release from ganglionated plexi (GPs) and associated nerves, were considered. The temporal pattern of ACh release, ACh(t), was simulated following a sinusoidal waveform of frequency 0.125 Hz to represent the respiratory frequency. Different mean concentrations and peak-to-peak ranges of ACh (ΔACh) were tested. We found that temporal variations in F f, F f(t), followed the simulated temporal ACh(t) pattern in all cases. The temporal mean of F f(t), , depended on the fibrillatory pattern (number and location of rotors), the percentage of ACh release nodes and . The magnitude of F f(t) modulation, ΔF f, depended on the percentage of ACh release nodes and ΔACh. The spatial pattern of ACh release did not have an impact on and only a mild impact on ΔF f. The f-wave frequency, being indicative of vagal activity, has the potential to drive autonomic-based therapeutic actions and could replace HRV markers not quantifiable from AF patients.

Localization and characterization of atrial depolarization waves on the surface electrocardiogram in dogs with rapid supraventricular tachycardia.

Supraventricular tachycardias (SVTs), despite having various anatomical substrates and pathophysiological mechanisms, frequently show similar electrocardiographic presentations. To locate and characterize atrial deflections (ADs) on 12-lead electrocardiograms in dogs with sustained rapid SVT and assess the utility of different electrocardiographic variables in differentiating types of tachycardia. Ninety-two dogs with orthodromic atrioventricular reciprocating tachycardia, 17 with atrial flutter, 33 with focal atrial tachycardia recorded and confirmed by electrophysiological study, and 40 dogs with sinus tachycardia. Atrial deflection position on the 12-lead surface electrocardiogram was assessed according to the sequence of intracardiac activation. Its features were evaluated together with the relationship between AD and QRS complex interval (AD-R) and QRS complex and AD interval (R-AD). Orthodromic atrioventricular reciprocating tachycardia was characterized by an AD-AD interval of 213 ± 30 ms, mean electrical axis (MEA) of AD of -90 (-90/-78)°, R-AD interval of 75 (65-80) ms, and R-AD/AD-R of 0.54 (0.45-0.64). Atrial flutter was characterized by an AD-AD interval of 199 ± 57 ms, MEA of 76° (72/81), R-AD of 120 (72-144) ms, and R-AD/AD-R of 0.81 (0.63-1.13). Focal atrial tachycardia was characterized by an AD-AD interval of 270 ± 38 ms, MEA of 49 (-72/76)°, R-AD of 160 (120-200) ms, and R-AD/AD-R of 1.45 (0.92-1.67). Sinus tachycardia was characterized by an AD-AD interval of 292 ± 31 ms, MEA of 66° (52/73), R-AD of 215 (192-222) ms, and R-AD/AD-R of 2.68 (2.25-3.08). Analyzing AD on 12-lead electrocardiogram is helpful in differentiating the most common SVTs in dogs.

Mechanical Wave Velocities in Left Ventricular Walls in Healthy Subjects and Patients With Aortic Stenosis

BackgroundMechanical wave velocity (MWV) measurement is a promising method for evaluating myocardial stiffness, because these velocities are higher in patients with myocardial disease. ObjectivesUsing high frame rate echocardiography and a novel method for detection of myocardial mechanical waves, this study aimed to estimate the MWVs for different left ventricular walls and events in healthy subjects and patients with aortic stenosis (AS). Feasibility and reproducibility were evaluated. MethodsThis study included 63 healthy subjects and 13 patients with severe AS. All participants underwent echocardiographic examination including 2-dimensional high frame rate recordings using a clinical scanner. Cardiac magnetic resonance was performed in 42 subjects. The authors estimated the MWVs at atrial kick and aortic valve closure in different left ventricular walls using the clutter filter wave imaging method. ResultsMechanical wave imaging in healthy subjects demonstrated the highest feasibility for the atrial kick wave reaching >93% for all 4 examined left ventricular walls. The MWVs were higher for the inferolateral and anterolateral walls (2.2 and 2.6 m/s) compared with inferoseptal and anteroseptal walls (1.3 and 1.6 m/s) (P < 0.05) among healthy subjects. The septal MWVs at aortic valve closure were significantly higher for patients with severe AS than for healthy subjects. ConclusionsMWV estimation during atrial kick is feasible and demonstrates higher velocities in the lateral walls, compared with septal walls. The authors propose indicators for quality assessment of the mechanical wave slope as an aid for achieving consistent measurements. The discrimination between healthy subjects and patients with AS was best for the aortic valve closure mechanical waves. (Ultrasonic Markers for Myocardial Fibrosis and Prognosis in Aortic Stenosis; NCT03422770)

Right heart catheterization predictors of symptomatic improvement in patients undergoing transcatheter tricuspid valve edge‐to‐edge repair

AbstractBackgroundTranscatheter tricuspid valve edge‐to‐edge repair (TTEER) is associated with improvement in outcomes for symptomatic patients with severe tricuspid regurgitation (TR). However, reliable predictors for clinical success are not yet fully defined. This study aims to describe right heart catheterization (RHC) findings in patients referred for TTEER and identify hemodynamic characteristics of patients who experience immediate symptomatic improvement following successful TR intervention.MethodsPatients who underwent TTEER and had a separate RHC within the preceding 6 months were included. Hemodynamic tracings from the RHC and TTEER procedures were reviewed and recorded. Clinical success was defined as a successful device implant with at least 1‐grade of TR reduction and improvement in NYHA class by 1 or more grades on 30‐day echocardiogram and clinical follow‐up.ResultsThirteen patients underwent an RHC within 6 months of TTEER procedure (median age 76 years [IQR: 73–80]). All patients were on a stable dose of loop diuretics. Baseline right atrial pressure was severely elevated (mean 19 mmHg [IQR: 9–24 mmHg]) with prominent CV waves. Median pulmonary capillary wedge pressure (PCWP) was 20 mmHg (IQR: 14–22) and 70% of patients had a mean PCWP &gt; 15 mmHg at rest. Median PCWP CV‐wave was 34 mmHg (IQR: 23–42). Higher PCWP CV‐wave height (40 mmHg [IQR 33–43] versus 18 mmHg [IQR 17–31]) was associated with lower likelihood of clinical success (OR 0.83, 95% CI: 0.35–0.97,p = 0.04).ConclusionsInclusion of invasive hemodynamics as part of pre‐TTEER evaluation may allow for improved TR phenotyping and patient selection. Patients with a large left atrial CV wave on resting RHC were less likely to experience immediate symptomatic improvement despite procedural success with TTEER.

Cardiovascular organ damage in relation to hypertension status in patients with ankylosing spondylitis

Purpose Hypertension is a major cardiovascular (CV) risk factor in ankylosing spondylitis (AS) patients. Less is known about the prevalence of CV organ damage in relation to hypertension status in AS patients. Materials and Methods CV organ damage was assessed by echocardiography, carotid ultrasound and pulse wave velocity (PWV) by applanation tonometry in 126 AS patients (mean age 49 ± 12 years, 39% women) and 71 normotensive controls (mean age 47 ± 11 years, 52% women). CV organ damage was defined as presence of abnormal left ventricular (LV) geometry, LV diastolic dysfunction, left atrial (LA) dilatation, carotid plaque or high pulse wave velocity (PWV). Results Thirty-four percent of AS patients had hypertension. AS patients with hypertension were older and had higher C-reactive protein (CRP) levels compared to AS patients without hypertension and controls (p < 0.05). The prevalence of CV organ damage was 84% in AS patients with hypertension, 29% in AS patients without hypertension and 30% in controls (p < 0.001). In multivariable logistic regression analyses, having hypertension was associated with a fourfold increased risk of CV organ damage independent of age, presence of AS, gender, body mass index, CRP, and cholesterol (odds ratio (OR) 4.57, 95% confidence interval (CI) 1.53 to 13.61, p = 0.006). In AS patients, presence of hypertension was the only covariable significantly associated with presence of CV organ damage (OR 4.40, 95% CI 1.40 to 13.84, p = 0.011). Conclusions CV organ damage in AS was strongly associated with hypertension, pointing to the importance of guideline-based hypertension management in AS patients.

PO-05-155 A CASE OF ALCOHOL LEADING TO ISOLATION IN THE ELECTROPHYSIOLOGY LABORATORY

Ligament of Marshall alcohol ablation is a treatment for refractory atrial fibrillation and left atrial flutter. Left atrial appendage (LAA) isolation resulting from LOM ablation has not been described. To describe a case of LOM alcohol ablation which resulted in left atrial appendage isolation and dissociation of a left atrial appendage reentrant atrial flutter from the atria. A middle aged man with a history of atrial fibrillation and multiple left atrial flutters was referred for repeat ablation after multiple prior unsuccessful ablations. He previously underwent surgical MAZE and 3 endocardial ablations including an anterior mitral line and endocardial and epicardial mitral isthmus line without achieving bidirectional block. He had recurrent, symptomatic atrial flutter despite therapy with dofetilide and metoprolol. The patient presented in an atypical flutter. The ligament of Marshall was cannulated and alcohol was sequentially injected for a total of 3.8 mL. After the first alcohol injection, the tachycardia abruptly terminated on the coronary sinus (CS) catheter and sinus rhythm resumed (Figure, blue arrows), though the surface ECG showed ongoing small atrial flutter waves (Figure, red arrows). Subsequent left atrial mapping confirmed that the left atrial appendage (LAA) was isolated from the remaining left and right atrium and remained in atrial flutter (Figure C). Overdrive pacing from a multipolar catheter in the LAA demonstrated a post-pacing interval within 20 ms of the tachycardia-cycle length (Figure C). Adenosine administration resulted in AV block but no alteration in tachycardia cycle-length. These findings were highly suggestive of a reentrant mechanism. Because 3D mapping was limited by dissociated CS and LAA rhythms, manual activation mapping was performed with earliest activation at the anterior superior LAA. RF ablation at this site resulted in atrial flutter slowing and termination. In a patient with LAA flutter and prior anteroseptal and lateral linear endocardial ablation, LOM alcohol ablation may isolate the LAA. This should be recognized when counseling patients and planning procedures.

Human atrial fibrillation and genetic defects in transient outward currents: mechanistic insights from multi-scale computational models.

Previous studies have linked dysfunctional Ito arising from mutations to KCND3-encoded Kv4.3 and KCND2-encoded Kv4.2 to atrial fibrillation. Using computational models, this study aimed to investigate the mechanisms underlying pro-arrhythmic effects of the gain-of-function Kv4.3 (T361S, A545P) and Kv4.2 (S447R) mutations. Wild-type and mutant Ito formulations were developed from and validated against experimental data and incorporated into the Colman et al. model of human atrial cells. Single-cell models were incorporated into one- (1D) and two-dimensional (2D) models of atrial tissue, and a three-dimensional (3D) realistic model of the human atria. The three gain-of-function mutations had similar, albeit quantitatively different, effects: shortening of the action potential duration; lowering the plateau membrane potential, abbreviating the effective refractory period (ERP) and the wavelength (WL) of atrial excitation at the tissue level. Restitution curves for the WL, the ERP and the conduction velocity were leftward shifted, facilitating the conduction of atrial excitation waves at high excitation rates. The mutations also increased lifespan and stationarity of re-entry in both 2D and 3D simulations, which further highlighted a mutation-induced increase in spatial dispersion of repolarization. Collectively, these changes account for pro-arrhythmic effects of these Kv4.3 and Kv4.2 mutations in facilitating AF. This article is part of the theme issue 'The heartbeat: its molecular basis and physiological mechanisms'.

ECHOCARDIOGRAPHIC CORRELATION BETWEEN LEFT ATRIAL INDICES AND LEFT VENTRICULAR FUNCTION (DIASTOLIC, SYSTOLIC DYSFUNCTION AND NORMO FUNCTION) IN HYPERTENSIVES

Purpose: Hypertension is known to cause changes in the LV that impact negatively on the LA both structurally and functionally posing clinically significant risk to patients. LA size assessment until recently was limited to determination of LA linear diameter and much has not been elucidated with respect to left atrial volume (indices) and cardiac indices as surrogates for LA and cardiac function. It is therefore important to see how LA indices (size, linear diameter and volume) cardiac indices relate to LV diastolic function among hypertensive subjects. To compare left atria indices with left ventricular function/dysfunction among hypertensive&#x0D; Methodology: It is an echocardiographic based descriptive cross-sectional study. A total of 200 hypertensive patients were recruited from the cardiology clinics using systematic sampling method.&#x0D; Results: Majority of the cases had isolated diastolic dysfunction n=149 (74.5%), thirty-six (18%) had normal diastolic and systolic functions while 7.5% had combined systolic and diastolic dysfunction (n=15). Left atrial maximum volume correlated significantly with E/E Prime (P= 0.003) and E/A Ratio (P= 0.003). While Left atrial pre-A wave volume (P=0.025), Left atrial diameter did not correlate with IVRT, E/E’, E/A ratio. Among the hypertensive patient’s E/E’ significantly correlated positively with all phasic LA volumes compared to E/A ratio. LV mass independently predicted all LA phasic volumes&#x0D; Unique Contribution to Theory, Policy and Practice: The study will create opportunity for clinician and policy makers to adopt measures to prevent progression into overt heart disease or failure

Correlation Between Left Atrial Indices and Left Ventricular Diastolic Function Among Hypertensive Patients

Purpose: To compare LA indices and cardiac indices among hypertensive with left ventricular diastolic dysfunction&#x0D; Methodology: It is an echocardiographic based descriptive cross-sectional study. A total of 200 hypertensive patients were recruited from the cardiology clinics using systematic sampling method.&#x0D; Results: The mean age of the study population was 58.7 ±13.96 (58.42±13.29 for Hypertensives) years while the median age was 59years.The female to male ratio was 1:6. Majority of the cases had isolated diastolic dysfunction n=149 (74.5%), thirty-six (18%) had normal diastolic and systolic functions while 7.5% had combined systolic and diastolic dysfunction (n=15). Left atrial maximum volume correlated significantly with E/E Prime (P= 0.003) and E/A Ratio (P= 0.003). While Left atrial pre-A wave volume (P=0.025), Left atrial diameter did not correlate with IVRT, E/E’, E/A ratio.&#x0D; Unique Contribution to Theory, Policy and Practice: Among the hypertensive patients E/E’ significantly correlated positively with all phasic LA volumes compared to E/A ratio. LV mass independently predicted all LA phasic volumes.

Atrial fibrillatory wave amplitude revisited: A predictor of recurrence after catheter ablation independent of the degree of left atrial structural remodeling.

The fibrillatory wave amplitude (FWA) during atrial fibrillation (AF) is thought to reflect structural atrial remodeling, but it remains unclear what determines the FWA. 114 consecutive patients were prospectively studied who underwent catheter ablation of AF. The mean FWA was computed by automated surface ECG analyses. The extent of the left atrial (LA) voltage-defined atrial fibrosis and conduction properties were estimated by a three-dimensional high-density electroanatomical mapping system. The LA size was evaluated by transthoracic echocardiography. The study patients were divided into 2 groups according to an FWA in lead V1 above the median value of 46 µV (high FWA group, n=57) or below 46 µV (low FWA group, n=57). There were no differences in the age, gender, CHADS2 score, prevalence of paroxysmal AF, medications, ablation strategy, and LA volume index between the two groups. The LA low voltage areas in the low FWA group were not different from those in the high FWA group. The total LA activation time and local LA conduction velocity did not differ between the two groups. During a median follow-up of 710 days, the recurrence rate after ablation was significantly higher in patients with a low FWA than a high FWA (log-rank P=0.02). In a multivariate analysis, non-paroxysmal AF, the LA volume index, and FWA were independent predictors of recurrence after ablation. The FWA was not correlated with the markers of atrial structural remodeling. Nevertheless, the FWA could still provide information for predicting the clinical outcome after AF ablation.

Differential Diagnostics of Wide QRS Complex Arrhythmias with Left Bundle Branch Block Morphology Using Slow Conduction Index

Differential diagnosis of wide QRS complex arrhythmias is one of the most challenging tasks in routine practice arrhythmology. The analysis of the wide QRS complex morphology has been introduced due to the complex problem of detecting atrial waves on ECG. A slow conduction index based on the ratio of the initial and terminal QRS amplitudes is one of the solutions to evaluate conduction velocity based on the surface ECG due to a significant variability of QRS morphology and real complexity of its detailed assessment. However, one of the significant limitations of this algorithm is a need to search for the RS wide complex type and randomly select an ECG lead with this morphology which can finally create a contradictory result.&#x0D; AIM: To evaluate a possibility of using the slow conduction index for differential diagnosis of wide QRS complex arrhythmias with left bundle branch (LBBB) morphology in any of 12-leads ECG followed by evaluation of the obtained diagnostic accuracy values.&#x0D; MATERIALS AND METHODS: The study included 280 single premature wide QRS complexes with LBBB morphology recorded during holter ECG monitoring in randomly selected 28 patients. Atrial extrasystoles were recorded in 14 patients and ventricular extrasystoles were captured during sinus rhythm in other 14 patients. A ROC analysis was used for the qualitative and quantitative assessment of a slow conduction index diagnostic values based on sensitivity (Sn), specificity (Sp) and accuracy (Acc).&#x0D; RESULTS: The highest values of Sn and Sp were obtained for a slow conduction index in the leads aVL, V2, aVF, V5 and III, and the lowest for the leads I, V3 and V6 based on the calculated area (AUC) under the ROC curves (p 0.001 for all leads).&#x0D; CONCLUSION: The study presented the fundamental possibility of using a slow conduction index in any of 12-lead ECG for the differential diagnosis of wide QRS complex arrhythmias with LBBB morphology.

A comparative study of the performance of methods for f-wave extraction

Objective. This study proposes a novel technique for atrial fibrillatory waves (f-waves) extraction and investigates the performance of the proposed method comparing with different f-wave extraction methods. Approach. We propose a novel technique combining a periodic component analysis (PiCA) and echo state network (ESN) for f-waves extraction, denoted PiCA-ESN. PiCA-ESN benefits from the advantages of using both source separation and nonlinear adaptive filtering. PiCA-ESN is evaluated by comparing with other state-of-the-art approaches, which include template subtraction technique based on principal component analysis, spatiotemporal cancellation, nonlinear adaptive filtering using an echo state neural network, and a source separation technique based on PiCA. Quality assessment is performed on a recently published reference database including a large number of simulated ECG signals in atrial fibrillation (AF). The performance of the f-wave extraction methods is evaluated in terms of signal quality metrics (SNR, ΔSNR) and robustness of f-wave features. Main results. The proposed method offers the best signal quality performance, with a ΔSNR of approximately 22 dB across all 8 sets of the reference database, as well as the most robust extraction of f-wave features, with 75% of all estimates of dominant atrial frequency well below 1 Hz.

Alteration of Pulmonary Venous Flow Doppler Post Transcatheter Closure of Atrial Septal Defect

Background: Atrial septal defect is a common congenital heart anomaly results in hemodynamically significant right ventriclular volume overload and an increase in the pulmonary venous flow.&#x0D; Aim: Evaluate changes of pulmonary venous flow parameters after transcatheter closure of secundum atrial septal defect.&#x0D; Patients and Methods: 50 patients with atrial septal defect aged from 3.5 to 31 years were included in the study. Pulmonary venous flow Doppler and right ventricular function were evaluated before and after successful transcatheter closure by transthoracic and transesophageal echocardiography.&#x0D; Results: The defect size ranged from 15 to 37mm with a mean (24.96 ±7.52), Normal systolic and diastolic waves of pulmonary venous flow Doppler were replaced by a continuous antegrade wave (mean 60±13.6 cm/s) in all atrial septal defect patients. Post-closure, the normal pulmonary venous flow pattern was regained, two separate waves, with a significant decrease in mean peak Systolic wave velocity (44.54±8.12 cm/sec vs 69.61±12.37, P=0.000), the mean peak Diastolic Wave velocity (55.85±9.81 cm/sec vs 72.65±10.38, P=0.000) and a significant increase in the mean peak atrial reversal wave velocity (28.75±4.63cm/sec vs 21.18±3.64, P=0.000). In multivariate regression analysis, significant predictors of haemodynamic significant ASD were ASD size,(odds ratio 1.508, P=0.007, 95% CI 1.153,2.671) and ASD/IAS ratio (odds ratio 2.313, P=0.001, 95% CI 1.064,3.104).&#x0D; Conclusions: Atrial septal defect patients have characteristic pulmonary venous flow pattern: continuous antegrade wave with systolic predominance and decrease in atrial reversal wave, which return to normal after closure. These changes could be helpful echocardiographic tool in prediction of successful closure of the defect.

Hemodynamic effect of pimobendan following intramuscular and intravenous administration in healthy dogs: A pilot study.

BackgroundPimobendan is widely used for the treatment of dogs with heart failure via the oral route. A new injectable form of pimobendan is now available and its potential usefulness via intravenous route has been recently demonstrated in dogs. However, the cardiovascular effects of intramuscular (IM) administration of injectable pimobendan have not been investigated yet.HypothesisIM administration of pimobendan may have the same hemodynamic effect as the IV route.MethodsSix healthy Beagle dogs underwent a placebo-controlled double-blind crossover study. The early cardiovascular effects after a single dose of IM and IV injections of pimobendan (0.2 ml/kg; Pimo IM and Pimo IV, respectively) were compared to the same volume of IM placebo (Saline IM) in anesthetized dogs. Clinical [heart rate (HR) and blood pressure (BP)] and echocardiographic hemodynamic parameters [left ventricular (LV) inflow waveforms of diastolic early wave (eV), atrial systolic wave (aV), diastolic early mitral ring velocity (e′), peak velocity (pV), stroke volume (SV), cardiac output (CO), and systemic vascular resistance (SVR)] were monitored with 15 min intervals for 120 min.ResultsDiastolic BP decreased significantly at 30 min in Pimo IM compared to Saline IM. Mean eV and CO values significantly increased from 75 min, e′ from 60 min, pV from 75 min, and SV from 15 to 120 min, whereas SVR significantly decreased at 30–60 min in Pimo IM compared to those of Saline IM (P < 0.05). Compared with the Pimo IV, eV and pV were significantly lower at 30–60 min (P < 0.05) while SV was significantly higher at 90–105 min in Pimo IM (P < 0.05). Other hemodynamic parameters (BP, HR, SVR, CO, e′, and E/e′) did not significantly change between Pimo IM and IV.ConclusionsThe hemodynamic effect of pimobendan following IM and IV injection was described. Our results suggested that IM administration of pimobendan is equally comparable and possibly interchangeable with IV administration. This warrant further studies to investigate the clinical effectiveness of IM pimobendan in treating dogs with congestive heart failure or in heart failure cases unable to receive IV or oral administration.

Leadless pacemaker technology: clinical evidence of new paradigm of pacing.

Despite continuous technological developments, transvenous pacemakers (PM) are still associated with significant immediate and long-term complications, mostly lead or pocket-related. Recent technological advances brought to the introduction in clinical practice of leadless PM for selected cohort of patients. These miniaturize devices are implanted through the femoral vein and advanced to the right ventricle, without leaving leads in place. Lack of upper extremity vascular access and/or high infective risk in patients requiring VVI pacing are the most common indications to leadless PM. The recently introduced MICRA AV leadless PM also allows ventricular synchronization through mechanical sensing of atrial contraction waves, thus solving the problem of AV synchronization. This review will discuss and summarize available clinical evidence on leadless PM, their performance compared to transvenous devices, current applications and future perspectives.

Himalayan Fibrillatory Waves in Juvenile Rheumatic Mitral Stenosis

Abstract An 18-year-old girl, a known case of rheumatic mitral stenosis, presented with dyspnea and palpitations. Electrocardiogram was done, which revealed atrial fibrillation and a large amplitude atrial fibrillatory wave, which was more than the voltage of R wave V1, a finding which is quite uncommon. Echocardiography revealed a large left atrium which was 80 mm in diameter. The patient was started on oral anticoagulation and referred for mitral valve replacement with maze procedure.