Sequential Intracardiac Activation Time Mapping of Arrhythmias Without Fiducial Time References.

Sequential local activation time (LAT) mapping of intracardiac electrograms' activations requires a stable reference signal to align recording phases. OBJECTIVE: This work's purpose is to develop an LAT mapping approach that does not rely on a time-alignment reference (TAR). METHODS: To create an LAT map in absence of TAR (TARLess), the coordinates and LATs of recording electrodes are collected sequentially; a bank of candidate functions (CFs) is constructed that contains constant binary level CFs and non-linear functions of recording points' coordinates. Finally, a subset of CFs is linearly combined to create an activation time function with output matching electrodes' LATs. Synthetic and clinical data were deployed to validate TARLess. A simple two-dimensional computer model was used to create 30 different wavefront collision scenarios in a region with spatial conduction heterogeneities. Furthermore, sequential recordings were collected from seven atrial fibrillation patients during stimulation from one or two sites, after sinus rhythm was achieved post catheter ablation. RESULTS: We showed that TARLess maps are similar to the one that uses TAR; for the 20 clinical maps, the mean absolute difference between measured LAT with the TAR and TARLess approach was 5.2 ±2.0 milliseconds. CONCLUSION: We developed a novel method to create an LAT map of sequential recordings without using any TAR and showed that it can create accurate maps even during the collision of multiple wavefronts. SIGNIFICANCE: TARLess mapping does not require a reference catheter which could lead to reduction in ablation procedure duration, cost, and potential complications.

Right atrial collision time (RACT): A novel marker of propensity for typical atrial flutter.

INTRODUCTION: The risk of typical atrial flutter (AFL) is increased proportionately to right atrial (RA) size or right atrial scarring that results in reduced conduction velocity. These characteristics result in propagation of a flutter wave by ensuring the macro re-entrant wave front does not meet its refractory tail. The time taken to traverse the circuit would take account of both of these characteristics and may provide a novel marker of propensity to develop AFL. Our goal was to investigate right atrial collision time (RACT) as a marker of existing typical AFL. METHODS: This single-centre, prospective study recruited consecutive typical AFL ablation patients that were in sinus rhythm. Controls were consecutive electrophysiology study patients >18 years of age. While pacing the coronary sinus (CS) ostium at 600 ms, a local activation time map was created to locate the latest collision point on the anterolateral right atrial wall. This RACT is a measure of conduction velocity and distance from CS to a collision point on the lateral right atrial wall. RESULTS: Ninety-eight patients were included in the analysis, 41 with atrial flutter and 57 controls. Patients with atrial flutter were older, 64.7 ± 9.7 versus 52.4 ± 16.8 years (<.001), and more often male (34/41 vs. 31/57 [.003]). The AFL group mean RACT (132.6 ± 17.3 ms) was significantly longer than that of controls (99.1 ± 11.6 ms) (p < .001). A RACT cut-off of 115.5 ms had a sensitivity and specificity of 92.7% and 93.0%, respectively for diagnosis of atrial flutter. A ROC curve indicated an AUC of 0.96 (95% CI: 0.93-1.0, p < .01). CONCLUSION: RACT is a novel and promising marker of propensity for typical AFL. This data will inform larger prospective studies.

Moving average and standard deviation thresholding (MAST): a novel algorithm for accurate R-wave detection in the murine electrocardiogram.

Advances in implantable radio-telemetry or diverse biologging devices capable of acquiring high-resolution ambulatory electrocardiogram (ECG) or heart rate recordings facilitate comparative physiological investigations by enabling detailed analysis of cardiopulmonary phenotypes and responses in vivo. Two priorities guiding the meaningful adoption of such technologies are: (1) automation, to streamline and standardize large dataset analysis, and (2) flexibility in quality-control. The latter is especially relevant when considering the tendency of some fully automated software solutions to significantly underestimate heart rate when raw signals contain high-amplitude noise. We present herein moving average and standard deviation thresholding (MAST), a novel, open-access algorithm developed to perform automated, accurate, and noise-robust single-channel R-wave detection from ECG obtained in chronically instrumented mice. MAST additionally and automatically excludes and annotates segments where R-wave detection is not possible due to artefact levels exceeding signal levels. Customizable settings (e.g. window width of moving average) allow for MAST to be scaled for use in non-murine species. Two expert reviewers compared MAST's performance (true/false positive and false negative detections) with that of a commercial ECG analysis program. Both approaches were applied blindly to the same random selection of 270 3-min ECG recordings from a dataset containing varying amounts of signal artefact. MAST exhibited roughly one quarter the error rate of the commercial software and accurately detected R-waves with greater consistency and virtually no false positives (sensitivity, Se: 98.48% ± 4.32% vs. 94.59% ± 17.52%, positive predictivity, +P: 99.99% ± 0.06% vs. 99.57% ± 3.91%, P < 0.001 and P = 0.0274 respectively, Wilcoxon signed rank; values are mean ± SD). Our novel, open-access approach for automated single-channel R-wave detection enables investigators to study murine heart rate indices with greater accuracy and less effort. It also provides a foundational code for translation to other mammals, ectothermic vertebrates, and birds.

Differences in Healthcare Use Between Patients With Persistent and Paroxysmal Atrial Fibrillation Undergoing Catheter-Based Atrial Fibrillation Ablation: A Population-Based Cohort Study From Ontario, Canada.

Background Patients with persistent atrial fibrillation (AF) undergoing catheter-based AF ablation have lower success rates than those with paroxysmal AF. We compared healthcare use and clinical outcomes between patients according to their AF subtypes. Methods and Results Consecutive patients undergoing AF ablation were prospectively identified from a population-based registry in Ontario, Canada. Via linkage with administrative databases, we performed a retrospective analysis comparing the following outcomes between patients with persistent and paroxysmal AF: healthcare use (defined as AF-related hospitalizations/emergency room visits), periprocedural complications, and mortality. Multivariable Poisson modeling was performed to compare the rates of AF-related and all-cause hospitalizations/emergency room visits in the year before versus after ablation. Between April 2012 and March 2016, there were 3768 consecutive patients who underwent first-time AF ablation, of whom 1040 (27.6%) had persistent AF. The mean follow-up was 1329 days. Patients with persistent AF had higher risk of AF-related hospitalization/emergency room visits (hazard ratio [HR], 1.21; 95% CI, 1.09-1.34), mortality (HR, 1.74; 95% CI, 1.15-2.63), and periprocedural complications (odds ratio, 1.36; 95% CI, 1.02-1.75) than those with paroxysmal AF. In the overall cohort, there was a 48% reduction in the rate of AF-related hospitalization/emergency room visits in the year after versus before ablation (rate ratio [RR], 0.52; 95% CI, 0.48-0.56). This reduction was observed for patients with paroxysmal (RR, 0.45; 95% CI, 0.41-0.50) and persistent (RR, 0.74; 95% CI, 0.63-0.87) AF. Conclusions Although patients with persistent AF had higher risk of adverse outcomes than those with paroxysmal AF, ablation was associated with a favorable reduction in downstream AF-related healthcare use, irrespective of AF type.

Radiotherapy for patients with cardiovascular implantable electronic devices: an 11-year experience.

PURPOSE: As cardiovascular implantable electronic devices (CIEDs) are increasingly indicated in older patients, and the burden of cancer is rising with the aging population, the management of patients with CIEDs who require radiotherapy (RT) is a timely concern. The objective of the study was to evaluate the management of, and malfunctions in, patients with CIEDs undergoing RT. METHODS: A retrospective study of patients with CIEDs receiving RT at Kingston Health Sciences Center from March 2007-April 2018 was conducted. Data on demographics, RT, devices, and management were compared for the primary outcome of device malfunction. RESULTS: Of the 189 patients with CIEDs receiving a total of 297 courses of RT, 4 patients (2.1%) experienced device malfunctions. Higher beam energy was associated with a malfunction (p < 0.05). Patients with malfunctions received a lower dose of radiation per fraction (267 ± 93 cGy vs. 477 ± 282 cGy; p < 0.05) and were significantly younger (71.4 ± 2.2 years vs. 77.8 ± 9.8 years; p < 0.01) compared to patients without malfunctions. CONCLUSION: RT-induced device malfunctions are rare, but given the potential complications, a better understanding of the potential predictors of malfunction and the development of evidence-based guidelines will help optimize patient safety.

Novel frequency analysis of signal-averaged electrocardiograms is predictive of adverse outcomes in implantable cardioverter defibrillator patients.

BACKGROUND: Current noninvasive risk stratification methods offer limited prediction of arrhythmic events when selecting patients for ICD implantation. Our laboratory has recently developed a signal processing metric called Layered Symbolic Decomposition frequency (LSDf) that quantifies the percentage of hidden QRS wave frequency components in signal-averaged ECG (SAECG) recordings. The purpose of this pilot study was to determine whether LSDf can be predictive of ventricular arrhythmia or death in an ICD patient cohort. METHODS AND RESULTS: Fifty-two ICD patients were recruited from 2008 to 2009. These were followed for a mean of 8.5 ± 0.4 years for the primary outcome of first appropriately treated ventricular arrhythmia (VT/VF) or death. Thirty-four subjects met the primary outcome. LSDf was significantly lower, and 12-lead QRS duration was significantly greater in patients meeting the primary outcome (12.14 ± 3.97% vs. 16.45 ± 3.73%; p = 0.001) and (111.59 ± 14.96 ms vs. 97.69 ± 13.51 ms; p = 0.012) respectively. A 13.25% LSDf threshold (0.74 sensitivity and 0.85 specificity) was selected based on an ROC curve. Kaplan-Meier survival analysis was conducted; patients above the 13.25% threshold demonstrated significantly better survival outcomes (log-rank p < 0.001). In Cox multivariate regression analysis, the LSDf threshold (13.25%) was compared to LVEF (28.5%), 12-lead QRSd (100 ms), age, % male sex, NYHA classification, and antiarrhythmic usage. LSDf was a predictor of the primary outcome (p = 0.005) and an independent predictor for solely ventricular arrhythmia (p = 0.002). CONCLUSION: Layered Symbolic Decomposition frequency analysis in SAECG recordings may be a viable predictor of negative ICD survival outcomes.

Ventricular substrate identification using close-coupled paced electrogram feature analysis.

AIMS: Substrate based catheter ablation strategies are widely employed for treatment of scar-related ventricular tachycardia (VT). We analysed intracardiac electrograms (EGMs) from close-coupled paced extrastimuli extracted from the EnSite Precision mapping system. We sought to characterize EGM responses of ventricular myocardium to varying coupling intervals from the right ventricular apex (RVA) in both healthy individuals and patients presenting with VT for catheter ablation. METHODS AND RESULTS: Extrastimuli were delivered from the RVA after estimation of the ventricular effective refractory period. Electrograms were recorded from high-density mapping catheters in the left ventricle and exported for analysis to MATLAB. Observational data were collected from 14 patients with ischaemic VT (mean age 72.4 ± 6.3 years, one female) and five controls (mean age 59.4 ± 7.4 years, one female). These derived data were used to inform an interventional strategy on a further 10 patients (mean age 64.7 ± 10.0 years; two female). Significant differences were observed in EGM duration (ED) and latency (LT) at all coupling intervals between VT patients and controls. Significant increases in ED and LT with decreased RVA coupling interval were observed at VT isthmuses. Abnormal responses derived from control subject data were used to classify four types of ventricular EGM response. Targeting sites with abnormal LT and ED significantly reduced VT inducibility (5/14 derivation patients to 0/10 intervention patients; P = 0.03). CONCLUSION: Paced electrogram feature analysis is a novel tool to characterize the ischaemic substrate. Association with VT isthmuses and early ablation results suggest a possible role in substrate ablation for ischaemic VT.

Augmenting Atrial Fibrillation Care After an Emergency Department Visit: Implementing Telephone Practice.

BACKGROUND: Between 2010 and 2012, the Heart Rhythm team in a tertiary care hospital completed a retrospective study that found that atrial fibrillation (AF) care can be episodic and heavily reliant on hospital resources, particularly the emergency department (ED). PROBLEM: Patients who attend the ED with AF are at high risk of hospital admission. APPROACH: A nurse practitioner (NP) was added to the Heart Rhythm team to create a program to improve AF care after an ED visit. Telephone practice was one of the many processes created. OUTCOMES: Findings revealed that 37 of 90 patients presented to the ED with AF prior to telephone contact and 7 of 90 patients did so post-telephone contact (P < .001). CONCLUSION: Telephone practice led by an NP provides an opportunity to improve assessment and management of patient with AF and offers a promising cost-effective method to reduce ED visits in the AF patient population.

Cardiac Conduction Velocity Estimation During Wavefront Collision.

Catheter ablation therapy is an effective approach to treat different arrhythmias. Cardiac conduction velocity (Cv), extracted from intracardiac electrograms, shows the speed and direction of the wavefront propagation at different sites and is an insightful feature to guide ablation therapy. To create a propagation map, a small mapping catheter with a high density of electrodes is usually used to sequentially collect electrograms from different sites in a desired chamber of the heart. The CV and isochrone surface estimations are very challenging during complex arrhythmias such as atrial fibrillation, where multiple wavefronts simultaneously excite different cardiac sites. Specifically, the performances of CV estimators significantly degrade at catheter sites where wave- fronts collide. This is mainly because during collision, different wavefronts pass the areas under different electrodes of the catheter. Consequently, the activation times of the electrodes are the results of different wavefronts, and there are sharp changes in isochrone line patterns in the vicinity of the collision's border. In this paper, we propose a method that is able to identify the collision sites and improve the estimation of CV and isochrone maps. The proposed method finds the electrodes of the catheter that are excited by a similar wavefront and then estimates the corresponding isochrone lines for that wavefront. Our simulation results confirmed the efficiency of the proposed method during collision.

Regional Dominant Frequency: A New Tool for Wave Break Identification During Atrial Fibrillation.

Cardiac mapping systems are based on the time/frequency feature analyses of intracardiac electrograms recorded from individual bipolar/unipolar electrodes. Signals from each electrode are processed independently. Such approaches fail to investigate the interrelationship between simultaneously recorded channels of any given mapping catheter during atrial fibrillation (AF). We introduce a novel signal processing technique that reflects regional dominant frequency (RDF) components. We show that RDF can be used to identify and characterize variation and disorganization in wavefront propagation- wave breaks. The intracardiac electrograms from the left atrium of 15 patients were exported to MATLAB and custom software employed to estimate RDF and wave break rate (WBR). We observed a heterogeneous distribution of both RDF and WBR; the two measures were weakly correlated (0.3; p < 0.001). We identified locations of AF or atrial tachycardia (ATach) termination and later compared offline with RDF and WBR maps. We inspected our novel metrics for associations with AF termination sites. Areas associated with AF termination demonstrated high RDF and low WBR (↑RDF,↓WBR). These sites were present in 14 of 15 patients (mean 2.6 ± 1.2 sites per patient; range, 1-4 sites), 43% situated within the pulmonary veins. In nine patients where AF terminated to sinus rhythm (6) or ATach (3), post-hoc analysis demonstrated all ↑RDF,↓WBR sites were ablated and correlated with AF termination sites. The proposed RDF signal processing tools can be used to identify and quantify wave break, and the combined use of these two novel metrics can aid characterization of AF. Further prospective studies are warranted.

Elevated Incidence of Atrial Fibrillation and Stroke in Patients With Atrial Flutter-A Population-Based Study.

BACKGROUND: The risk of stroke from atrial flutter and its relationship with progression to atrial fibrillation (AF) is unclear. This study describes the incidence of AF and stroke in patients with atrial flutter, and whether atrial flutter ablation attenuates the incidence of AF and stroke. METHODS: We performed a population-based retrospective cohort study of adults with typical atrial flutter with no AF history. Using linked health administrative databases we defined 3 cohorts: (1) adult patients diagnosed with new isolated atrial flutter; (2) a contemporary, 1-to-1 matched cohort from the Ontario population; and (3) patients with isolated atrial flutter who underwent atrial flutter ablation. RESULTS: A total of 9339 new typical atrial flutter patients were identified and 7248 were matched to general population subjects. Over the 3-year follow-up, AF occurred in 40.4% of patients with atrial flutter, and 3.3% of the matched general population (rate ratio, 12.2; P < 0.001). Stroke occurred in 4.1% of patients with atrial flutter and 1.2% of the general population cohort (rate ratio, 3.4; P < 0.001). Among 218 patients who had an atrial flutter ablation, AF occurred in 47 (21.6%) over the following 3 years, and incidence of stroke was between 0 and 2.3%. CONCLUSIONS: Patients with isolated atrial flutter develop AF and stroke at a higher rate than the general population. Catheter ablation reduces but does not eliminate future AF incidence and stroke risk and continued anticoagulation after successful atrial flutter ablation might therefore be warranted.

Quality of life with ablation or medical therapy for ventricular arrhythmias: A substudy of VANISH.

BACKGROUND/OBJECTIVE: We compared health-related quality of life (HRQoL) in patients randomized to escalated therapy and those randomized to ablation for ventricular tachycardia in the VANISH trial. METHODS: HRQoL was assessed among VANISH patients at baseline and 3-, 6-, and 12-month follow-up visits. Four validated instruments were used: the SF-36, the implanted cardioverter defibrillator (ICD) Concerns questionnaire (ICDC), the Hospital Anxiety and Depression Scale (HADS), and the EuroQol five dimensions questionnaire (EQ-5D). Linear mixed-effects modeling was used for repeated measures with SF-36, HADS, ICDC, and EQ-5D as dependent variables. In a second model, treatment was subdivided by amiodarone use prior to enrollment. RESULTS: HRQoL did not differ significantly between those randomized to ablation or escalated therapy. On subgroup analysis, improvement in SF-36 measures was seen at 6 months in the ablation group for social functioning (63.5-69.3, P = 0.03) and energy/fatigue (43.0-47.9, P = 0.01). ICDC measures showed a reduction in ICD concern in the ablation group at 6 months (10.4-8.7, P = 0.01) and a reduction in ICD concern in the escalated therapy group at 6 months (10.9-9.4, P = 0.04). EQ-5D measures showed a significant improvement in overall health in ablation patients at 6 months (63.4-67.3, P = 0.04). CONCLUSION: Patients in the VANISH study randomized to ablation did not have a significant change in quality of life outcomes compared to those randomized to escalated therapy. Some subgroup findings were significant, as those randomized to ablation showed persistent improvement in SF-36 energy/fatigue and ICD concern, and transient improvement in SF-36 social functioning and EQ-5D overall health.

Relative timing of near-field and far-field electrograms can determine the tachyarrhythmia site of origin.

BACKGROUND: Despite improving algorithms, inappropriate shocks for supraventricular tachycardia (SVT) still occur in a significant number of patients with implantable cardioverter-defibrillators (ICDs). This makes the discovery of novel discriminators that use existing ICD hardware an attractive proposition. OBJECTIVE: We hypothesized that the delay of activation onset from the device-detected, far-field electrogram (EGM) to the near-field, bipole EGM would allow the differentiation of ventricular tachycardias (VTs) from SVTs. METHODS: Proof of principle was demonstrated by rapid pacing in the right atrium, right ventricle, and left ventricle in healthy patients undergoing atrial fibrillation ablation procedures (n = 17). Using real-life ICD recordings, the equivalent measurements were made in a derivation cohort (n = 26) and cutoff predictive values obtained. Finally, the selected values were validated in a separate group of recordings (n = 82). RESULTS: In healthy patients, significant differences in the far-field to near-field EGM activation onsets were observed between right atrial (14.7 ± 2.7 ms), right ventricular (36.3 ± 8 ms), and left ventricular (57.8 ± 10.3 ms; P < .001) pacing. In the derivation ICD cohort, the median far-field to near-field onset delay was significantly shorter in SVT (24.5 ms; interquartile range, 15.3-47.5 ms) than in VT (118.5 ms; interquartile range, 102.5-131.5 ms) (P < .001). Using a cutoff of 100 ms in the validation cohort, SVT was successfully discriminated from VT with a sensitivity and specificity of 88% and a negative predictive value of 94.2%. CONCLUSION: The delay between far-field and near-field EGMs offers a potential new discrimination tool to reduce inappropriate ICD therapies and aid interpretation of single-lead device tracings.

A Comparison of the Efficacy of Voltage-directed Cavotricuspid Isthmus Ablation Using Mini Versus Conventional Electrodes.

Cavotricuspid isthmus (CTI) ablation is a current first-line management method for typical atrial flutter. A voltage-directed technique that systematically targets points of maximal voltage has be found to reduce procedure and fluoroscopy times without increasing recurrence. We hypothesized that this technique's efficiency would be enhanced by using signals from radial minielectrodes of a novel catheter (IntellaTip MiFi™; Boston Scientific, Natick, MA, USA). Prospectively, atrial flutter patients underwent voltage-directed ablation with a nonirrigated 8-mm-tip catheter. Ablation was either directed by conventional bipolar electrodes (group A, n = 13) or mini-electrodes (group B, n = 17) with the goal of achieving bidirectional block at the CTI and a subsequent observation time of 30 minutes. Total radiofrequency application time and lesion numbers were not significantly different. Group B had a lower mean power [38.7 watts (W) ± 2.0 W versus 44.8 W ± 1.9 W; p < 0.05] and a tendency for longer fluoroscopy and procedure times. In three of the cases in group B, a switch to an irrigated catheter was required in order to achieve bidirectional block. In group A, bidirectional block was obtained in all patients using the nonirrigated catheter with no significant increase in reconnection. Differences in the catheter performance between the two groups were driven by poorer performance of the MiFi™ catheter (Boston Scientific, Natick, MA, USA) in patients presenting in atrial flutter. Electroanatomical mapping revealed a more proximal localization of the maximal voltage by the minielectrodes as compared with the conventional bipolar electrodes, resulting in less efficient identification and ablation of the conducting muscle bundles. Final results indicated CTI ablation using minielectrodes is not superior to conventional bipolar electrodes in the use of 8-mm, nonirrigated electrodes.

Clinical Role of Dominant Frequency Measurements in Atrial Fibrillation Ablation - A Systematic Review.

INTRODUCTION: Experimental data strongly supports a role for high-frequency sources in the perpetuation of atrial fibrillation, it follows that identification of areas exhibiting spectra containing high dominant frequencies (DF) may represent perpetuating sources and targeted elimination might terminate AF. The aim of this review is to present and critically appraise the literature on DF studied in association with AF ablation. METHODS AND RESULTS: A systematic review was done including the PubMed (MEDLINE), Cochrane Central Register of Controlled Trials (Central), Scientific Electronic Library Online (SciELO), and HighWire Press databases. The searches were made by combining the terms "Dominant Frequency", "Atrial Fibrillation", and "Catheter Ablation" and their translations for the English and non-English based databases. Ten articles were selected from a total of 327 articles found after the initial search. The ablation strategy varied, most studies performed pulmonary vein isolation alone or associated with complex fractionated atrial electrogram ablation with or without an additional intervention. The use or not of DF sites as ablation target was distinguishable between the articles. Four articles ablated DF sites as a major intervention or in addition to a traditional approach. The remaining 6 articles assessed DF sites pre and post ablation and associated these data with clinical outcome. CONCLUSION: No prior study has systematically comprised information for clinical use of DF. The current literature supports global DF as a useful marker of ablation outcome; however direct intervention targeting DF appears premature with mixed results and too few studies.

Bipolar Intracardiac Electrogram Active Interval Extraction During Atrial Fibrillation.

OBJECTIVE: We introduce novel methods to identify the active intervals (AIs) of intracardiac electrograms (IEGMs) during complex arrhythmias, such as atrial fibrillation (AF). METHODS: We formulate the AI extraction problem, which consists of estimating the beginning and duration of the AIs, as a sequence of hypothesis tests. In each test, we compare the variance of a small portion of the bipolar IEGM with its adjacent segments. We propose modified general-likelihood ratio (MGLR) and separating-function-estimation tests; we derive five test statistics (TSs), and show that the AIs can be obtained by threshold crossing the TSs. We apply the proposed methods to the IEGM segments collected from the left atrium of 16 patients (62.4 ± 8.2-years old, four females, four paroxysmal, and twelve persistent AF) prior to catheter ablation. The accuracy of our methods is evaluated by comparing them with previously developed methods and manual annotation (MA). RESULTS: Our results show a high level of similarity between the AIs of the proposed methods and MA, e.g., the true and false positive rates of one of the MGLR-based methods were, respectively, 97.8% and 1.4%. The mean absolute error from estimation of the onset and end of AIs and also for the estimation of the mean cycle length for that approach was 8.7 ± 10.5, 13 ± 15.5, and 4.2 ± 9.4 ms, respectively. CONCLUSION: The proposed methods can accurately identify onset and duration of AI of the IEGM during AF. SIGNIFICANCE: The proposed methods can be used for real-time automated analysis of AF, the most challenging complex arrhythmia.

Antimicrobial Natural Product Berberine Is Efficacious for the Treatment of Atrial Fibrillation.

The purpose of this study is to test the efficacy of bioactive natural product berberine in the treatment of patients with atrial fibrillation (AF). Data of 45 paroxysmal AF patients treated with berberine and 43 age, gender, New York Heart Association functional classification score, and concomitant cardiovascular disease matched patients treated with amiodarone were analyzed retrospectively to examine conversion rate, average conversion time, average heart rate, and echocardiographic parameters. There was no statistical difference between berberine and amiodarone on conversion rate or echocardiographic parameters. Berberine treatment showed a significantly longer average time to conversion and higher heart rate during sinus rhythm (SR) than amiodarone. Echocardiographic parameters showed that E/A ratio and left atrial diameter were significantly improved after 6- and 12-month berberine treatment, but only E/A ratio improved significantly at the same time points after amiodarone treatment. This is the first report to specifically compare efficacy of berberine and amiodarone in the treatment of patients with AF. We find that berberine and amiodarone are equally effective for conversion of AF and maintenance of normal SR.