Advances in management of premature ventricular contractions

A "two-step classification" machine learning method for non-invasive localization of premature ventricular contraction origins based on 12-lead ECG

BACKGROUND

Premature ventricular contraction (PVC) is a type of cardiac arrhythmia that originates from ectopic pacemaker in the ventricles. The localization of the origin of PVC is essential for successful catheter ablation. However, most studies on non-invasive PVC localization focus on elaborate localization in specific regions of the ventricle. This study aims to propose a machine learning algorithm based on 12-lead electrocardiogram (ECG) data that can improve the accuracy of PVC localization in the whole ventricle.

METHODS

We collected 12-lead ECG data from 249 patients with spontaneous or pacing-induced PVCs. The ventricle was divided into 11 segments. In this paper, we propose a machine learning method consisting of two consecutive classification steps. In the first classification step, each PVC beat was labeled to one of the 11 ventricular segments using six features, including a newly proposed morphological feature called "Peak_index." Four machine learning methods were tested for comparative multi-classification performance and the best classifier result was kept to the next step. In the second classification step, a binary classifier was trained using a smaller combination of features to further differentiate segments that are easily confused.

RESULTS

The Peak_index as a proposed new classification feature combined with other features is suitable for whole ventricle classification by machine learning methods. The test accuracy of the first classification reached 75.87%. It is shown that a second classification for confusable categories can improve the classification results. After the second classification, the test accuracy reached 76.84%, and when a sample classified into adjacent segments was considered correct, the test "rank accuracy" was improved to 93.49%. The binary classification corrected 10% of the confused samples.

CONCLUSION

This paper proposes a "two-step classification" method to localize the origin of PVC beats into the 11 regions of the ventricle using non-invasive 12-lead ECG. It is expected to be a promising technique to be used in clinical settings to help guide ablation procedures.

Impact of anesthetic management on catheter ablation for premature ventricular complexes: insights during the COVID-19 outbreak

BACKGROUND

The influence of divergent anesthesia types during ablation of premature ventricular complexes (PVCs) is not known. While previously performed under general anesthesia (GA) at our institution, these procedures were exclusively performed under local anesthesia (LA) ± minimal sedation during the COVID-19 outbreak for logistic reasons.

METHODS

One hundred and eight consecutive patients (82 GA versus 26 LA) undergoing PVC ablation at our center were evaluated. Intraprocedural PVC burden (over 3 min) pre-ablation was measured twice: (1) at the start (before GA induction) and (2) before catheter insertion (after GA induction). Upon cessation of ablation and after a waiting period of ≥ 15 min, acute ablation success (AAS) was defined as absence of PVCs until the end of the recording period.

RESULTS

Intraprocedural PVC burden was not significantly different between LA versus GA group: (1) 17.8 ± 3% vs 12.7 ± 2%, P = 0.17 and (2) 10.0 ± 3% vs 7.4 ± 1%, P = 0.43, respectively. Activation mapping-based ablation was performed significantly more in the LA vs GA group (77% vs 26% of patients, P < 0.001, respectively). AAS was significantly higher in LA vs GA group: 22/26 (85%) vs 41/82 (50%), respectively, P < 0.01. After multivariable analysis, LA was the only independent predictor for AAS (OR 13, 95% CI 1.57-107.4, P = 0.017).

CONCLUSION

Ablation of PVC under LA presented significantly higher AAS rate compared to GA. The procedure under GA might be complicated by PVC inhibition (after catheter insertion/during mapping) and PVC disinhibition post-extubation.

Ventricular tachycardia ablation in children

INTRODUCTION

The ablation of ventricular tachycardia, including premature ventricular contractions, is an approved, albeit infrequent procedure in pediatric patients. Data are scarce regarding the outcomes of this procedure. The purpose of this study was to share a high-volume center experience and patient outcomes for catheter ablation of ventricular ectopy and ventricular tachycardia in pediatric population.

METHODS

Data were retrieved from the institutional data bank. Outcomes over time were evaluated, and procedural details were compared.

RESULTS

A total of 116 procedures were performed on 102 pediatric patients between July 2009 and May 2021 at the Rajaie Cardiovascular Medical and Research Center in Tehran, Iran. Ablation was not performed in 4 procedures (3.4%) due to high-risk substrates. Of the remaining 112 ablations performed, 99 (88.4%) were successful. However, one patient died due to a coronary complication. There were no significant differences observed in early ablation results based on patients' age, sex, cardiac anatomy, or ablation substrates (P > 0.05). Follow-up records were available for 80 procedures, and 13 (16.3%) of those experienced recurrence. During long-term follow-up, none of the variables mentioned above were statistically different between patients with or without arrhythmia recurrence.

CONCLUSION

The overall success rate of pediatric ventricular arrhythmia ablation is favorable. We found no significant predictor for the procedural success rate concerning acute and late outcomes. Larger multicenter studies are needed to elucidate the predictors and outcomes of the procedure.

Computational modelling of mechano-electric feedback and its arrhythmogenic effects in human ventricular models

The current study aims to investigate the role of mechano-electric feedback (MEF) in healthy cardiac cycles and in cardiac arrhythmia using human ventricular models. The numerical formulation of stretch-activated channels (SACs) in terms of the fibre stretch of the myocardium is incorporated into the modified Hill model that describes the myocardium as an electro-visco-active material. Additionally, we propose models of SACs formulated in terms of the rate of stretch along fibre direction and the stretch along sheet direction. We analyze the effect of the three different models for SACs and different material properties on the regular cycles by using electrocardiogram and volume-time curves, and show that the each model of SACs has regionally different influences on the heart model. Moreover, we simulate 'commotio cordis' and 'precordial thump' and demonstrate that MEF plays a major role in the occurrence of fibrillation and defibrillation in the absence of the structural cardiac damage. Furthermore, we study the role of MEF in premature ventricular contraction when the blood pressure is disturbed.

Predictors of positive response to beta-blockers for treatment of premature ventricular complexes

BACKGROUND

The aim of the present study is to investigate the possible factors that might be predictive of effective antiarrhythmic effect of beta-blockers on premature ventricular complexes (PVC).

METHODS

Data of 190 eligible consecutive patients to whom beta-blocker therapy had been initiated for treatment of PVC's were retrospectively evaluated. The Holter recording acquired before beta-blocker initiation and the first Holter acquired after beta blocker initiation during follow up was comprehensively evaluated for each patient. Parameters obtained from pre- and post-beta-blocker 24 h Holter recordings were compared with each other and possible predictors were evaluated for positive response to beta-blocker therapy.

RESULTS

Sixty-one patients (32.1%) were observed to respond beta-blocker therapy with at least 50% reduction of daily PVC burden. Patients who responded to beta-blockers had significantly higher ratio of patients who had positive correlation between hourly heart rate and corresponding hourly PVC number (fast HR-PVC status) compared with non-responders (73.8% vs 48.1%, p < 0.001). Binary logistic regression analysis revealed PVC QRS width (Odds ratio: 0.971; p: 0.037) and fast HR-PVC status (Odds ratio: 2.935; p: 0.007) as the independent predictors of positive response to beta-blockers for treatment of PVC.

CONCLUSION

Positive correlation between hourly heart rate and PVC incidence was found to be independent positive predictor and PVC QRS width was found to be independent negative predictor of beta-blocker success in our study. This observation might have important clinical implications to guide medical treatment of PVCs in clinical practice.

Tp-Te interval and Tp-Te/QT ratio may be predictive of idiopathic ventricular tachycardia in patients with frequent outflow tract premature ventricular complexes

BACKGROUND

The aim of present study is to evaluate the predictive value of QTc dispersion, Tp-Te interval and Tp-Te/QT ratio for idiopathic monomorphic outflow tract ventricular tachycardia (VT) occurrence in patients with frequent idiopathic outflow tract premature ventricular complexes (PVCs).

METHODS

A total of 180 patients (49.2 ± 13.6 years, 74 male) who had undergone outflow tract PVC ablation between 01 January 2015 and 01 November 2018 constituted our study population. Patients with isolated outflow tract PVC without any VT recording on Holter recordings and without any inducible VT at EPS were classified as isolated PVC group. Patients with any episode of VT that has the same morphology with outflow tract PVC were classified as nonsustained or sustained VT groups based on the duration of VT episode. QTc dispersion, Tp-Te and Tp-Te/QT ratio values were calculated and compared between groups.

RESULTS

There were 116 patients with isolated PVC, 35 patients with nonsustained VT and 29 patients with sustained VT. QTc dispersion, Tp-Te and Tp-Te/QT ratio values were significantly lower in patients with isolated PVC compared to patients with nonsustained or sustained VT episodes. Tpeak to Tend interval greater than 110.5 msec on derivation V6 predicted VT occurrence with 93.8% sensitivity and 82.8% specificity. Tpeak to Tend/QT interval greater than 0.27 on derivation V6 predicted VT occurrence with 93.8% sensitivity and 0.81% specificity.

CONCLUSION

Tp-Te interval and Tp-Te/QT ratio on derivation V6 may aid in prediction of presence of outflow tract VT in clinical practice.

Acute effect of outflow tract premature ventricular complex ablation on QT dispersion, Tp-e interval and Tp-e/QT ratio

BACKGROUND

There is limited data regarding the effect of idiopathic premature ventricular complexes (PVC) on myocardial repolarisation. Most of PVC's originate from right and left ventricular outflow tracts (RVOT and LVOT).

AIM

The aim of this study is to evaluate the acute effect of outflow tract PVC ablation on electrocardiographic repolarisation markers.

METHODS

A total of 180 patients (49.2 ± 13.6 years, 74 male) without any exclusion criteria who had undergone outflow tract PVC ablation between 1 January 2015 and 1 November 2018 constituted our study population. Electrocardiographic recordings that had been obtained before and after ablation procedure on the same day were retrospectively evaluated for the QTc dispersion, Tp-e interval, Tp-e/QT ratio and Tp-e/QTc ratio. Significance of difference between pre- and postablation values was tested.

RESULTS

There was no significant difference regarding QTc dispersion between pre- and post-ablation state (36.5 ± 20.9 vs. 35.3 ± 16.4 ms, p: NS). However, Tp-e and Tp-e/QT values in all lateral precordial derivations were observed to decrease significantly after PVC ablation (in the respective order on derivation V5: 104.0 ± 21.6 ms vs. 91.1 ± 14.8 ms, p<.001 and 0.26 ± 0.05 vs. 0.23 ± 0.04, p<.001).

CONCLUSIONS

Based on these observations, it may be suggested that frequent outflow tract PVC's increase transmural dispersion of repolarisation and this effect is attenuated by catheter ablation in the acute phase. Results of further prospective studies are required for evaluation of the long term effects of PVC ablation on myocardial repolarisation.

A Novel Model Based on Spatial and Morphological Domains to Predict the Origin of Premature Ventricular Contraction

Pace mapping is commonly used to locate the origin of ventricular arrhythmias, especially premature ventricular contraction (PVC). However, this technique relies on clinicians’ ability to rapidly interpret ECG data. To avoid time-consuming interpretation of ECG morphology, some automated algorithms or computational models have been explored to guide the ablation. Inspired by these studies, we propose a novel model based on spatial and morphological domains. The purpose of this study is to assess this model and compare it with three existing models. The data are available from the Experimental Data and Geometric Analysis Repository database in which three in vivo PVC patients are included. To measure the hit rate (A hit occurs when the predicted site is within 15 mm of the target) of different algorithms, 47 target sites are tested. Moreover, to evaluate the efficiency of different models in narrowing down the target range, 54 targets are verified. As a result, the proposed algorithm achieves the most hits (37/47) and fewest misses (9/47), and it narrows down the target range most, from 27.62 ± 3.47 mm to 10.72 ± 9.58 mm among 54 target sites. It is expected to be applied in the real-time prediction of the origin of ventricular activation to guide the clinician toward the target site.

Predictors of adequate intraprocedural premature ventricular complex (PVC) frequency during idiopathic PVC ablation

BACKGROUND

The aim of the present study was to determine the predictors of adequate intraprocedural premature ventricular complex (PVC) frequency for successful mapping and ablation of idiopathic PVCs.

METHODS

A total of 101 consecutive patients (45 men; age: 47.9 ± 14.2 years) who had undergone idiopathic PVC ablation between 01 November 2018 and 24 June 2020 constituted our study population. Clinical and demographic data, procedural details and 24 h rhythm recordings that had been recorded before the procedure were retrospectively evaluated. Total PVC burden and diurnal variability assessed by the ratio of night time (22:00-06:00) over day time (06:00-22:00) PVC burden was calculated. The relationship between hourly PVC number and heart rate was also evaluated for each patient. Clinical characteristics and Holter parameters were compared between groups with and without adequate intraprocedural frequency of PVCs that permitted activation mapping.

RESULTS

In all, 27 patients (26.7%) had infrequent intraprocedural PVCs which necessitated isoproterenol infusion or cancellation of ablation procedure due to inability of activation mapping. PVC burden was significantly higher in the group with frequent intraprocedural PVCs (26.1 ± 9.4% vs 21.2 ± 10.3%; p: 0.026). There were no significant differences between groups regarding the relationship between hourly PVC number and heart rate or the ratio of night/day PVC burden. Binary logistic regression analysis revealed the 24 h Holter PVC burden as the sole parameter that is significant predictor of frequent intraprocedural PVCs permitting activation mapping.

CONCLUSION

The 24 h PVC burden was the only predictor of adequate intraprocedural PVC frequency permitting activation mapping during idiopathic PVC ablation.

Prognostic significance of accelerated ventricular response during radiofrequency ablation of premature ventricular complexes

Background

Accelerated ventricular response is frequently observed during radiofrequency ablation (RFA) of premature ventricular complexes (PVCs). We hypothesized that acceleration indicates an appropriate site and adequate injury to the arrhythmogenic tissue, and sought to investigate its value in predicting the outcome.

Methods

We retrospectively analyzed RFA procedures performed for PVCs in our institution from 2011 to 2019.

Results

Fifty-eight patients (29 male; age 42.7 ± 15.6 years) underwent 62 RFA procedures. The most common site was the right ventricular outflow tract (67.7%). Acute success was seen in 88.7%. Accelerated ventricular response was observed in 60.0% of the successful procedures. After a median follow-up of 14.0 months (IQR: 6.0–26.6 months), 16 patients had a recurrence. Recurrence was significantly lower in the group with acceleration than in the group without acceleration (12.5% vs. 57.1%; log-rank P < 0.001). The 1-year recurrence rate was 6.5% in the acceleration group and 41.6% in the group without acceleration. On multivariable analysis the adjusted hazard ratio was 0.17 (95% CI, 0.04–0.64; Cox regression P = 0.009). The sensitivity, specificity, positive predictive, and negative predictive values of accelerated response to predict long-term success were 75.7%, 75.0%, 87.5%, and 57.2%, respectively.

Conclusions

The recurrence after PVC ablation is significantly lower when an accelerated response was observed at the successful location during RFA. This can be an additional useful marker of long-term success.

Elimination of Benign Ventricular Premature Beats or Ventricular Tachycardia with Catheter Ablation versus Two Different Optimal Antiarrhythmic Drug Treatment Regimens (Sotalol or Verapamil/Flecainide)

BACKGROUND

Symptomatic idiopathic ventricular arrhythmias (VA), including premature beats (VPB) and nonsustained ventricular tachycardia (VT) are commonly encountered arrhythmias. Although these VA are usually benign, their treatment can be a challenge to primary and secondary health care providers. Mainstay treatment is comprised of antiarrhythmic drugs (AAD) and, in case of drug intolerance or failure, patients are referred for catheter ablation to tertiary health care centers. These patients require extensive medical attention and drug regimens usually have disappointing results. A direct comparison between the efficacy of the most potent AAD and primary catheter ablation in these patients is lacking. The ECTOPIA trial will evaluate the efficacy of 2 pharmacological strategies and 1 interventional approach to: suppress the VA burden, improve the quality of life (QoL), and safety.

HYPOTHESIS

We hypothesize that flecainide/verapamil combination and catheter ablation are both superior to sotalol in suppressing VA in patients with symptomatic idiopathic VA.

STUDY DESIGN

The Elimination of Ventricular Premature Beats with Catheter Ablation versus Optimal Antiarrhythmic Drug Treatment (ECTOPIA) trial is a randomized, multicenter, prospective clinical trial to compare the efficacy of catheter ablation versus optimal AAD treatment with sotalol or flecainide/verapamil. One hundred eighty patients with frequent symptomatic VA in the absence of structural heart disease or underlying cardiac ischemia who are eligible for catheter ablation with an identifiable monomorphic VA origin with a burden ≥5% on 24-h ambulatory rhythm monitoring will be included. Patients will be randomized in a 1:1:1 fashion. The primary endpoint is defined as >80% reduction of the VA burden on 24-h ambulatory Holter monitoring. After reaching the primary endpoint, patients randomized to one of the 2 AAD arms will undergo a cross-over to the other AAD treatment arm to explore differences in drug efficacy and QoL in individual patients. Due to the use of different AAD (with and without β-blocking characteristics) we will be able to explore the influence of alterations in sympathetic tone on VA burden reduction in different subgroups. Finally, this study will assess the safety of treatment with 2 different AAD and ablation of VA.

Renal denervation as a synergistic tool for the treatment of polymorphic ventricular ectopic beats: A case report

INTRODUCTION

Ventricular ectopic beats (VEBs) are very common and often occur in hypertensive or obese individuals, as well as in patients presenting with either sleep apnea or structural cardiac disease. Sympathetic overactivity plays a crucial role in the development, continuation, and exacerbation of ventricular arrhythmias. Recent studies have reported the relevance of sympathetic activation in patients with ventricular arrhythmias and suggested a potential role for catheter-based renal denervation (RDN) in reducing the arrhythmic burden.

PATIENT CONCERNS

We describe a 38-year-old female symptomatic patient that at the time of presentation was complaining of fatigue in response to minor and medium efforts and not tolerating any physical activity, and episodes of tachycardia associated with dyspnoea, pre-syncope, and syncope.

DIAGNOSIS

She had a high incidence of polymorphic VEBs on 24-hour-Holter monitoring who also presented with left ventricular (LV) hypertrophy for which she was treated with bisoprolol 10 mg/d. The 24-hour-Holter on bisoprolol at baseline showed sinus rhythm with an average heart rate of 92 bpm. There were 44,743 isolated VEBs. A total of 2538 nonsustained ventricular tachycardia events were registered. Her cardiac magnetic resonance imaging showed an increase in LV diastolic diameter and impairment of the right ventricle.

INTERVENTIONS

The patient underwent endocardial ablation of the right ventricular outflow tract and the LV free lateral wall, and concomitantly underwent bilateral RDN.

OUTCOMES

Three months post-procedure, her 24-hour-Holter off medication demonstrated an average heart rate 72 bpm and a substantially reduced number of 2823 isolated monomorphic VEBs. Thus far, 18-months follow-up, she has been asymptomatic and doing physical exercises.

CONCLUSION

In our current patient, we used RDN as a synergistic method to attenuate the sympathetic overactivity, which is narrowly linked to VEBs appearance. Our case report highlighted that RDN may become a potential adjuvant treatment for VEBs in the future.

Localization of origins of premature ventricular contraction in the whole ventricle based on machine learning and automatic beat recognition from 12-lead ECG

OBJECTIVE

The localization of origins of premature ventricular contraction (PVC) is the key factor for the success of ablation of ventricular arrhythmias. Existing methods rely heavily on manual extraction of PVC beats, which limits their application to the automatic PVC recognition from long-term data recorded by ECG monitors before and during operation. In addition, research identifying PVC sources in the whole ventricle have not been reported. The purpose of this study was to validate the feasibility of localization of origins of PVC in the whole ventricle and to explore an automatic algorithm for recognition of PVC beats based on long-term 12-lead ECG.

APPROACH

This study included 249 patients with spontaneous PVCs or pacing-induced PVCs. A novel algorithm was used to automatically extract PVC beats from a massive amount of original ECG data, which was collected by different acquisition devices. After clustering and labelling, 374 sample groups, each containing dozens to hundreds of PVC beats, formed the entire dataset of 11 categories corresponding to 11 regions of PVC origins in the whole ventricle. To choose the best classification model for the current task, four machine learning methods, support vector machine (SVM), random forest (RF), gradient-boosting decision tree (GBDT) and Gaussian naïve Bayes (GNB), were compared by randomly selecting 70% of the entire dataset (sample groups = 257) for training and the remaining 30% (sample groups = 117) for testing. The average performance of each model was estimated by the bootstrap method using 1000 resampling trials.

MAIN RESULTS

For PVC beat recognition, the achieved testing accuracy, sensitivity and specificity is 97.6%, 98.3% and 96.7%, respectively. For localization purpose, the achieved testing accuracy varies slightly from 70.7% to 74.1% among four classifiers, and when neighboring regions were combined, the testing rank accuracy is improved to a range of 91.5% to 93.2%.

SIGNIFICANCE

The proposed algorithm can automatically recognize PVC beats and map them to one of the 11 regions in the whole ventricle. Owing to the high accuracy of PVC beat recognition and the capability to target the potential PVC origins in multi regions, it is expected to be a predominant technique being used in clinical settings to automatically analyze huge ECG data before and during operation so as to replace the tedious manual identification.

Investigation of the Cellular Pharmacological Mechanism and Clinical Evidence of the Multi-Herbal Antiarrhythmic Chinese Medicine Xin Su Ning

Xin Su Ning (XSN), a China patented and certified multi-herbal medicine, has been available in China since 2005 for treating cardiac ventricular arrhythmia including arrhythmia induced by ischemic heart diseases and viral myocarditis, without adverse reactions being reported. It is vitally important to discover pharmacologically how XSN as a multicomponent medicine exerts its clinical efficacy, and whether the therapeutic effect of XSN can be verified by standard clinical trial studies. In this paper we report our discoveries in a cellular electrophysiological study and in a three-armed, randomized, double-blind, placebo-controlled, parallel-group, multicenter trial. Conventional electrophysiological techniques were used to study the cellular antiarrhythmic mechanism of XSN. Data was then modeled with computational simulation of human action potential (AP) of the cardiac ventricular myocytes. The clinical trial was conducted with a total of 861 eligible participants randomly assigned in a ratio of 2:2:1 to receive XSN, mexiletine, or the placebo for 4 weeks. The primary and secondary endpoint was the change of premature ventricular contraction (PVC) counts and PVC-related symptoms, respectively. This trial was registered in the Chinese Clinical Trial Register Center (ChiCTR-TRC-14004180). We found that XSN prolonged AP duration of the ventricular myocytes in a dose-dependent, reversible manner and blocked potassium channels. Patients in XSN group exhibited significant total effective responses in the reduction of PVCs compared to those in the placebo group (65.85% vs. 27.27%, P < 0.0001). No severe adverse effects attributable to XSN were observed. In conclusion, XSN is an effective multicomponent antiarrhythmic medicine to treat PVC without adverse effect in patients, which is convincingly supported by its class I & III pharmacological antiarrhythmic mechanism of blocking hERG potassium channels and hNaV1.5 sodium channel reported in our earlier publication and prolongs AP duration both in ventricular myocytes and with computational simulation of human AP presented in this report.

Premature ventricular contractions cause a position shift in 3D mapping systems: analysis, quantification, and correction by hybrid activation mapping

Aims

Using a modified CARTO 3D mapping system, we studied if premature ventricular contractions (PVCs) cause position shifts within the 3D co-ordinate system. We quantified magnitude of the phenomenon and corrected for it, by creating both an activation map that represents the conventional local activation time (LAT) and one corrected for this position shift (hybrid LAT map).

Methods and results

We prospectively enrolled patients planned for PVC ablation. Distances between the earliest LAT, the earliest hybrid-LAT, and the best pacemap positions were calculated in a 3D model. Ablation was performed at the best hybrid-LAT location. Efficacy was evaluated by acute response to ablation as well as clinical outcome on 24-h Holter at 1 year. One hundred and twenty-seven LAT-hybrid pairs were studied in 18 patients (age 48.3 ± 18.0 years, 12 female). Baseline PVC burden was 16 ± 12%. The mean position shift between LAT-hybrid and its associated LAT position was 8.9 ± 5.5 mm. The mean position shift between best LAT-hybrid and best pacemap was 6.2 ± 5.0 mm and the mean shift between best conventional LAT and best pacemap was 13.5 ± 7.0 mm (P &lt; 0.0001 for all pairwise comparisons). Exclusive targeting of best LAT-hybrid position resulted in acute abolition of PVC activity in all patients. After 1-year follow-up, mean PVC burden reduction was 16% (baseline) to &lt;1%.

Conclusion

Premature ventricular contractions cause a position shift in 3D mapping systems compared with the same endocardial position in sinus rhythm. An approach to account for this phenomenon, correct it and target exclusively the adjusted 3D position is feasible and highly efficient in terms of acute and 1-year clinical outcome after radiofrequency ablation.

Catheter-induced premature ventricular complexes (PVCs) may aid in the determination of optimal timing for clinical PVC ablation

BACKGROUND

The aim of the present study is to evaluate whether catheter-induced premature ventricular complexes (PVCs) produced at the presumptive ablation site may aid in the identification of the optimal timing of the earliest local activation for the successful ablation of clinical PVCs.

METHODS

Sixty-three consecutive patients (35 males, age: 53.5 ± 14.4 years) without any exclusion criteria who had undergone PVC ablation between 1 July 2018 and 1 July 2019 constituted our study population. The time interval between the beginning of the EGM and the beginning of the QRS of each catheter-induced PVC (Cath EGM-ECG) and the time interval between the beginning of the EGM of clinical PVCs at the earliest site and the beginning of the QRS of clinical PVCs (PVC earliest EGM-ECG) were noted for each patient. The value of Cath EGM-ECG as a reference for procedural success of ablation was evaluated by examining the relationship between Cath EGM-ECG and PVC earliest EGM-ECG.

RESULTS

Fifty-two patients had successful ablation, and 43 of them (82.7%) had PVC earliest EGM-ECG values greater than or equal to Cath EGM-ECG. Eleven patients had procedural failure, and all of them had PVC earliest EGM-ECG values lower than Cath EGM-ECG. A PVC earliest EGM-ECG value -1.5 ms greater than Cath EGM-ECG predicted successful ablation with a sensitivity of 90.4% and a specificity of 100.0% in the general patient population.

CONCLUSION

Cath EGM-ECG seems to serve as a reliable guide for finding the optimal timing of the earliest site for successful PVC ablation.

Comparative spatial resolution of 12-lead electrocardiography and an automated algorithm

BACKGROUND

The spatial resolution of pacemapping using 12-lead electrocardiography (ECG) or PaSo software is unknown.

OBJECTIVE

The purpose of this study was to determine the spatial resolution of traditional ECG pacemapping and pacemapping using the PaSo coefficients.

METHODS

Seventeen patients undergoing ablation of supraventricular tachycardias or atrioventricular node were included. After ablation, chamber (right ventricular outflow tract/rest of the right ventricle/left ventricle) geometry was created with Carto 3. Pacingwas performed from any point in these cardiac regions, the QRS morphology being the template and the point being considered as arrhythmia "origin." Subsequently, pacing was performed from points around the "origin" (1538 points). The QRS of these tagged points were compared by traditional ECG pacemapping and PaSo coefficients. The spatial resolution was calculated using correlations between the distance away from the origin (measured by 3 computational methods) and traditional ECG pacemapping and PaSo coefficients, independently.

RESULTS

A 0.01-unit decrease in the PaSo coefficient resulted in 1.1 mm increased Cartesian distance (95% confidence interval [CI] 0.9-1.3 mm; P < .001) and 2.4 mm increased geodesic distance (95% CI 1.9-2.9 mm; P < .001) and 664 mm³ increase in convex hull volume (95% CI 423-906 mm³; P < .0001). For traditional ECG pacemapping, each decrease in lead match resulted in 1.7 mm increased Cartesian distance (95% CI 1.5-2.0 mm; P < .001) and 3.4 mm increased geodesic distance (95% CI 2.8-4.1 mm; P < .001) and 712 mm³ increase in convex hull volume (95% CI 599-830 mm³; P < .0001). Both PaSo coefficients and traditional pacemapping showed a significant inverse linear correlation with distance from the "origin."

CONCLUSION

The resolution of mapping using the Paso software is better than that of traditional pacemapping.

Ion Channel Targeted Mechanisms of Anti-arrhythmic Chinese Herbal Medicine Xin Su Ning

Xin Su Ning (XSN) is a China patented and certified herbal medicine used to treat premature ventricular contractions (PVCs) since 2005. A recent completed clinical trial of 861 patients showed that XSN had similar PVC inhibition rate to the class I antiarrhythmic drug mexiletine, at 65.85% for XSN and 63.10% for mexiletine. We have previously reported that XSN prolongs action potential duration (APD) and suppresses action potential amplitude (APA) of the cardiac ventricular myocytes. In this report we aim to reveal the effect of XSN on the ionic channels that govern APD and APA, which would help to explain the cellular electrophysiological mechanism of XSN. Our main findings are: (1) On ECG recorded in isolated rat, in the presence of XSN the amplitude of R wave was significantly decreased and the amplitude of T wave was increased significantly; (2) XSN blocked hNaV1.5 channel stably transfected cell line in a dose-dependent manner with an IC₅₀ of 0.18 ± 0.02 g/L; and (3) XSN suppresses hERG channels in a dose-dependent manner with an IC₅₀ of 0.34 ± 0.01 g/L. In conclusion, the clinical antiarrhythmic efficacy of XSN is based on its class I and Class III antiarrhythmic properties by suppression hNaV1.5 channel and hERG channels, which are directly responsible for XSN’s effect on APA suppression and APD prolongation.

Ablation of unmappable ventricular parasystole originating from the right ventricular outflow tract: a case report

Background

When the coupling interval is matched, ventricular parasystole can form a stable fusion QRS complex with sinus rhythm. Ablation of a fusion QRS complex has been rarely reported and is unexpectedly difficult.

Case presentation

We describe a case of ventricular parasystole from muscle sleeves of the right ventricular outflow tract. The patient was a 54-year-old woman who was admitted to the hospital because of frequent palpitations for 3 months. Anti-arrhythmic drugs had been ineffective, and she had no history of cardiovascular disease. Because the fusion QRS complex interfered with the conventional mapping technique, we could not eliminate the ventricular parasystole successfully.

Results and conclusions

Finally, we used the reversed U curve method and found that the source of ventricular arrhythmia was in the right cusp according to the special local potential. A fusion QRS complex formed by ventricular parasystole and nodal ventricular activation make mapping and ablation difficult. The special local potential was the only evidence available to confirm the target of ablation satisfactorily.

Is There any Relationship Between Myocardial Repolarization Parameters and the Frequency of Ventricular Premature Contractions?

BACKGROUND

Ventricular premature contractions (VPCs) may trigger lethal ventricular arrhythmias in patients with structural heart disease. However, this role of VPCs in healthy people remains controversial once that not enough clinical trials are available. Recently, some myocardial repolarization markers, such as Tp-e interval, Tp-e/QT, and Tp-e/QTc ratios, have been reported to be useful for predicting lethal ventricular arrhythmias in various clinical disorders without structural heart disease.

OBJECTIVE

In this study, we aimed to investigate the relation between VPC frequent and myocardial repolarization markers in individuals without structural heart disease.

METHODS

This study included 100 patients who had complaints of dizziness and palpitations. Twelve-lead electrocardiography and 24-hour ambulatory Holter recordings were obtained from all patients. VPC burden was calculated as the total number of VPCs divided by the number of all QRS complexes in the total recording time. P-values < 0.05 were considered significant.

RESULTS

Tp-e interval and Tp-e/QTc ratio were significantly higher in patients with higher VPC burden than in patients with lower VPC burden, and a positive correlation was found between these markers and VPC burden. Tp-e (β = 1.318, p = 0.043) and Tp-e/QTc (β = -405.136, p = 0.024) in the lead V5 were identified as independent predictors of increased VPC burden.

CONCLUSIONS

Tp-e interval and Tp-e/QTc ratio increased in patients with high VPC number. Our study showed that VPCs may have a negative effect on myocardial repolarization. This interaction may lead to an increased risk of malignant arrhythmias.

Endocardial ablation of ventricular ectopic beats arising from the basal inferoseptal process of the left ventricle

BACKGROUND

Idiopathic ventricular ectopy (VE) shows predilection to sites within the left ventricular (LV) base such as the outflow tract/aortic sinuses, LV summit, and areas adjacent to the aortomitral continuity. We characterize VE arising from the inferior septum of the LV base that was successfully managed by LV endocardial ablation from the inferoseptal recess of the LV.

OBJECTIVE

The purpose of this study was to determine the incidence, electrocardiographic (ECG) findings, electrophysiological findings, and anatomical features associated with VE arising from the basal inferoseptal process of the LV (ISP-LV) ablated using an LV endocardial approach via the inferoseptal recess of the LV.

METHODS

A total of 425 consecutive patients undergoing VE ablation between January 1, 2012 and December 31, 2016 at 3 centers were evaluated. Demographic characteristics, ECG findings, and procedural data were analyzed for patients with ISP-LV VEs.

RESULTS

Seven (1.5%) had a site of origin from the ISP-LV. Common ECG findings were a right bundle branch block concordant pattern or an atypical left bundle branch block early transition pattern, suggestive of a basal origin with a left superior axis, a biphasic QRS complex in lead aVR, and a small s wave in lead V₆. Earliest activation was seen in an area below the outflow tract accessed from the inferoseptal recess inferior to the His bundle. In 3 cases, transient junctional rhythm was seen during ablation. All cases were ablated successfully with no complications.

CONCLUSION

VE arising from the ISP-LV represents a distinct subset of idiopathic arrhythmia and can be successfully treated by endocardial catheter ablation from the inferoseptal recess. They share common surface ECG and electrophysiological findings with special anatomical features that need recognition for successful catheter ablation.

Catheter ablation of symptomatic idiopathic ventricular arrhythmias : A five-year single-centre experience

Aims

This study was designed to gain insight into the patient characteristics, results and possible complications of ablation procedures for symptomatic idiopathic premature ventricular complexes (PVC) and idiopathic ventricular tachycardia (VT).

Methods

Data were collected from all patients who underwent radiofrequency catheter ablation for symptomatic PVCs and idiopathic VT in the Catharina Hospital between 1 January 2011 and 31 December 2015. The procedural endpoint was elimination or non-inducibility of the clinical arrhythmia. Successful sustained ablation was defined as the persistent elimination of at least 80% of the PVCs or the absence of VTs at follow-up. In case of suspected PVC-induced cardiomyopathy, the systolic left ventricular function was reassessed 3 months post procedure.

Results

Our cohort consisted of 131 patients who underwent one or more ablation procedures; 99 because of symptomatic premature ventricular complexes, 32 because of idiopathic VT. In total 147 procedures were performed. The procedural ablation success rate was 89%. Successful sustained ablation rate was 82%. Eighteen (13.2%) patients had suspected PVC-induced cardiomyopathy. In 15 of them (83%), successful sustained ablation was achieved and the left ventricular ejection fraction improved from a mean of 39% (±8.8) to 55.4% (±8.1). Most arrhythmias originated from the right ventricular outflow tract (60%) or aortic cusps (13%). Complications included three tamponades.

Conclusion

Catheter ablation therapy for idiopathic ventricular arrhythmias is very effective with a sustained success rate of 82%. In patients with PVC-induced cardiomyopathy, it leads to improvement of systolic left ventricular function. However, risk for complications is not negligible, even in experienced hands.

The effect of the physical activity on polymorphic premature ventricular complexes in chronic kidney disease

BACKGROUND

Polymorphic premature ventricular complexes (PVCs) are very common, appearing most frequently in patients with hypertension, obesity, sleep apnea, and structural heart disease. Sympathetic hyperactivity plays a critical role in the development, maintenance, and aggravation of ventricular arrhythmias. Endurance exercise training clearly lowers sympathetic activity in sympatho-excitatory disease states and may be tolerated by patients with chronic kidney disease (CKD).

METHODS

We assessed 40 CKD patients with hypertension with polymorphic PVCs. Patients underwent a complete medical history and physical examination. We evaluated the effectiveness of β blocker only or β blocker + exercise during 12 months of follow-up regarding the changes of the numbers of PVCs and mean heart rate (HR) by 24-hour-Holter.

RESULTS

We observed in the β blocker group a significant decrease in the number of polymorphic PVCs from baseline 36,515 ± 3,518 to 3, 6, 9 and 12 months of follow-up, 28,314 ± 2,938, 23,709 ± 1,846, 22,564 ± 1,673, and 22,725 ± 1,415, respectively (P < 0.001). In the β blocker + exercise group a significant decrease in the number of polymorphic PVCs also occurred from baseline 36,091 ± 3,327 to 3, 6, 9 and 12 months of follow-up, 29,252 ± 3,211, 20,948 ± 2,386, 14,238 ± 3,338, and 6,225 ± 2,319, respectively (P < 0.001). Comparisons between the two groups at the same time point showed differences from the sixth month onwards: the 6th (Δ = -2,761, P = 0.045), 9th (Δ = -8,325, P < 0.001) and 12th (Δ = -16,500, P < 0.001) months. There was an improvement during the 12 months of follow-up vs. baseline, after the β blocker or β blocker + exercise in mean 24-hour HR Holter monitoring, creatinine values, eGFR, and ACR.

CONCLUSION

Polymorphic PVCs may be modifiable by physical activity in CKD patients with hypertension without structural heart disease.

Assessment of subtle cardiac dysfunction in patients with frequent premature ventricular complexes by real-time three-dimensional speckle tracking echocardiography

BACKGROUND

To evaluate subtle and early premature ventricular complex (PVC)-induced ventricular impairment in patients with frequent PVCs and without structural heart disease by real-time 3-dimensional (3D) speckle tracking echocardiography (RT3D-STE).

HYPOTHESIS

Patients with frequent premature ventricular complexes with normal left ventricular ejection fraction have subtle left ventricular dysfunction.

METHODS

Forty patients (22 male) with a single source of frequent PVCs and 40 healthy controls (24 male) underwent assessment by conventional 2-dimensional (2D) echocardiography and RT3D-STE. Left ventricular ejection fraction (LVEF), and global longitudinal, circumferential, radial, and area strain (GLS, GCS, GRS, and GAS, respectively) and individual segment strain were calculated using off-line analysis software and compared between the 2 groups.

RESULTS

There were no significant differences in baseline clinical or 2D echocardiographic variables including LVEF between groups. However, all RT3D-STE assessed variables, including GLS, GCS, GRS, GAS, and individual segment strain, were significantly lower (P < 0.05) in the PVC group than the control group, and showed strong correlations, most prominently GCS (r = -0.84, P = 0.020), with LV function as assessed by LVEF. 3D-STE measurements showed good intraobserver, interobserver, and test-retest agreement.

CONCLUSIONS

In patients with frequent PVCs and normal LVEF, 3D -STE revealed lower global and regional strain values than in healthy controls. RT3D-STE is a novel, feasible and reproducible method to assess cardiac function and appears suitable to detect subtle left ventricular dysfunction.

Tp-e interval and Tp-e/QT ratio before and after catheter ablation in patients with premature ventricular complexes

Aim: Tp-e/QT ratio is a novel marker of ventricular repolarization. The aim of the study is to evaluate the Tp-e interval and Tp-e/QT ratio before and after radiofrequency ablation (RFA) for patients with frequent premature ventricular complexes (PVCs). Patients & methods: The study included 151 consecutive patients who underwent RFA for treatment of symptomatic frequent PVCs. Results: Tp-e interval, Tp-e/QT ratio and Tp-e/QTc ratio (all p < 0.001) were significantly different before and after RFA. After the procedure, mean left ventricular ejection fraction of the population were significantly increased than before RFA (p < 0.001). There was a significant correlation between preprocedural Tp-e/QTc ratio and PVC burden in patients (p = 0.023). Conclusion: Our study shows that PVCs may have a negative effect on ventricular repolarization.

Proof of concept study: renal sympathetic denervation for treatment of polymorphic premature ventricular complexes

BACKGROUND OR PURPOSE

Polymorphic premature ventricular complexes (PVCs) are very common, appearing most frequently in patients with hypertension, obesity, sleep apnea, and structural heart disease. Sympathetic hyperactivity plays a critical role in the development, maintenance, and aggravation of ventricular arrhythmias. Recently, the relevance of sympathetic activation in patients with ventricular arrhythmias was reported, and this finding suggested a potential role for catheter-based renal sympathetic denervation in reducing the arrhythmic burden.

METHODS

We evaluated the effectiveness of the renal sympathetic denervation (RSD) in comparison to antiarrhythmic pharmacologic therapy in reducing polymorphic PVCs refractory to medication therapy and cardiac parameters assessed by 24-h Holter monitoring and cardiac magnetic resonance (CRM), respectively, in patients with structurally normal heart.

RESULTS

Thirty-four patients were included in this study, 14 served as control, and 20 were treated with an ablation cardiac catheter with open irrigated tip. RSD was performed by a single operator following the standard technique. All the patients included had polymorphic PVCs and structurally normal heart. Data were obtained at baseline at the 12th month of follow-up (sixth month after RSD or adjustment of antiarrhythmic dosage). In RSD group, we observed a significant decrease in the number of polymorphic PVCs from baseline 36,091 ± 3327 to 3, 6, 7 (first month after RSD, without drugs), and 12 months (sixth month after RSD, without drugs) of follow-up, 31,009 ± 3251, 20,411 ± 3820, 7701 ± 1549, and 1274 ± 749, respectively, in all patients, P < 0.0001 to all the comparisons between the mean of each time point with the mean of every other time point. No changes in mean 24-h ABPM and renal function in both groups were observed at 12th month of follow-up. However, 24-h Holter mean heart rate decreased in control group at 12th month of follow-up, which did not happen with the RSD group. At the sixth month post-RSD in comparison to baseline, a significant reduction in the number of polymorphic PVCs (∆ = -34,817 ± 3590, P < 0.0001) was observed, as well as, in CRM parameters such as left ventricular mass/body surface area (∆ = -5.4 ± 2.1 g/m², P < 0.0001) and left ventricular ejection fraction (∆ = +3.0 ± 1.8 %, P < 0.0001). In comparison to control group at the same time point, these findings were statistically superior in RSD group (P > 0.05). A significant correlation was found between the Δ number of polymorphic PVCs at the sixth month (r = -0.6723, P = 0.0012) after the RSD and the total number of RSD ablated spots.

CONCLUSIONS

Polymorphic PVCs refractory to medication therapy may be modifiable by RSD in patients without structural heart disease. Although encouraging, our data are preliminary and need to be validated in a large population and in long term.

Ablating Premature Ventricular Complexes: Justification, Techniques, and Outcomes

We reviewed the underlying principles that allow for safe and effective ablation for premature ventricular complexes. Clinical scenarios that necessitate consideration for ablation, the underlying anatomy, and the unique consideration to maximize energy delivery without compromising safety are sequentially examined.

The Efficacy and Safety of Wenxin Keli in Patients with Frequent Premature Ventricular Contractions: A Randomized, Double-blind, Placebo-controlled, Parallel-group, Multicenter Trial

BACKGROUND

Premature ventricular contractions (PVCs) are common in the general population, and frequent PVCs may result in the poor quality of life or even the damage of cardiac function. We examined the efficacy and safety of a traditional Chinese medicine Wenxin Keli for the treatment of frequent PVCs among a relatively large Chinese cohort.

METHODS

We performed a randomized, double-blind, placebo-controlled, parallel-group, multicenter trial. A total of 1200 eligible participants were randomly assigned in a ratio of 1:1 to receive Wenxin Keli or the placebo for 4 weeks. The primary and secondary endpoint was the change of PVC numbers and PVC-related symptoms after a 4-week treatment compared with baseline, respectively. In addition, vital signs, laboratory values, and electrocardiographic parameters were assessed in a safety analysis.

RESULTS

At the initial evaluation, no significant differences in the baseline characteristics were observed between the Wenxin Keli group and the placebo group. A smaller number of PVCs was observed after the 4-week treatment than at baseline, in both the Wenxin Keli group (5686 ± 5940 vs. 15,138 ± 7597 beats/d, P < 0.001) and the placebo group (10,592 ± 8009 vs. 14,529 ± 5929 beats/d, P < 0.001); moreover, the Wenxin Keli group demonstrated a significantli greater reduction in the frequency of PVCs than the placebo group (P < 0.001). In a full analysis set, patients in the Wenxin Keli group exhibited significantly higher total effective responses in the reduction of PVCs compared to those in the placebo group (83.8% vs. 43.5%,P < 0.001). The per-protocol analysis yielded similar results (83.0% vs. 39.3%,P < 0.001). Treatment with Wenxin Keli also demonstrated superior performance compared to the placebo with respect to PVC-related symptoms. No severe adverse effects attributable to Wenxin Keli were reported.

CONCLUSIONS

Wenxin Keli treatment effectively reduced the overall number of PVCs and alleviated PVC-related symptoms in patients without structural heart diseases and had no severe side effects.

A Case Report of Renal Sympathetic Denervation for the Treatment of Polymorphic Ventricular Premature Complexes: Expanding Horizons

Premature ventricular complexes are very common, appearing most frequently in patients with hypertension, obesity, sleep apnea, and structural heart disease. Sympathetic hyperactivity plays a critical role in the development, maintenance, and aggravation of ventricular arrhythmias. Recently, Armaganijan et al reported the relevance of sympathetic activation in patients with ventricular arrhythmias and suggested a potential role for catheter-based renal sympathetic denervation in reducing the arrhythmic burden. In this report, we describe a 32-year-old hypertensive male patient presenting with a high incidence of polymorphic premature ventricular complexes on a 24  hour Holter monitor. Beginning 1 year prior, the patient experienced episodes of presyncope, syncope, and tachycardia palpitations. The patient was taking losartan 100  mg/day, which kept his blood pressure (BP) under control, and sotalol 160  mg twice daily. Bisoprolol 10  mg/day was used previously but was not successful for controlling the episodes. The 24  hour Holter performed after the onset of sotalol 160  mg twice daily showed a heart rate ranging between 48 (minimum)-78 (average)-119 (maximum) bpm; 14,286 polymorphic premature ventricular complexes; 3 episodes of nonsustained ventricular tachycardia, the largest composed of 4 beats at a rate of 197 bpm; and 14 isolated atrial ectopic beats. Cardiac magnetic resonance imaging with gadolinium perfusion performed at rest and under pharmacological stress with dipyridamole showed increased left atrial internal volume, preserved systolic global biventricular function, and an absence of infarcted or ischemic areas. The patient underwent bilateral renal sympathetic denervation. The only drug used postprocedure was losartan 25  mg/day. Three months after the patient underwent renal sympathetic denervation, the mean BP value dropped to 132/86  mmHg, the mean systolic/diastolic 24  hour ambulatory BP measurement was reduced to 128/83  mmHg, and the 24  hour Holter monitor showed a heart rate ranging between 51 (minimum)-67 (average)-108 (maximum) bpm, 854 polymorphic premature ventricular complexes, and no episodes of nonsustained ventricular tachycardia.

An unusual case of nonsustained ventricular tachycardia

A 54-year-old woman with advanced cirrhosis secondary to hepatitis C, end-stage kidney failure on hemodialysis, and nonischemic cardiomyopathy was admitted to the medical intensive care unit for treatment of a superior vena cava (SVC) thrombus involving a recently implanted cardioverter-defibrillator (ICD). During her hospitalization, the patient abruptly developed frequent ventricular ectopy with up to 20 beat runs of hemodynamically significant nonsustained ventricular tachycardia. Because ventricular ectopy was not previously seen in the patient, the sudden onset prompted a thorough evaluation. After other causes were excluded, a recently placed scopolamine patch was removed; the ventricular ectopy completely resolved within 24 hours and did not recur for the remainder of the patient's extended hospitalization. While anticholinergic syndrome is associated with a vagally mediated sinus tachycardia, ventricular arrhythmias have not previously been reported with scopolamine, to the best of the authors' knowledge. The observed cardiac side effects of scopolamine rarely occur at therapeutic doses. Scopolamine is metabolized primarily in the liver and excreted by the kidneys, so renal and hepatic impairment should be considered when initiating and dosing this medication. Because anticholinergic medications including scopolamine are commonly used in various clinical settings, we believe that clinicians should be aware of this significant but completely reversible adverse effect.

Expanding application of the Wiggers diagram to teach cardiovascular physiology

Dr. Carl Wiggers' careful observations have provided a meaningful resource for students to learn how the heart works. Throughout the many years from his initial reports, the Wiggers diagram has been used, in various degrees of complexity, as a fundamental tool for cardiovascular instruction. Often, the various electrical and mechanical plots are the novice learner's first exposure to simulated data. As the various temporal relationships throughout a heartbeat could simply be memorized, the challenge for the cardiovascular instructor is to engage the learner so the underlying mechanisms governing the changing electrical and mechanical events are truly understood. Based on experience, we suggest some additions to the Wiggers diagram that are not commonly used to enhance cardiovascular pedagogy. For example, these additions could be, but are not limited to, introducing the concept of energy waves and their role in influencing pressure and flow in health and disease. Also, integrating concepts of exercise physiology, and the differences in cardiac function and hemodynamics between an elite athlete and normal subject, can have a profound impact on student engagement. In describing the relationship between electrical and mechanical events, the instructor may find the introduction of premature ventricular contractions as a useful tool to further understanding of this important principle. It is our hope that these examples can aid cardiovascular instructors to engage their learners and promote fundamental understanding at the expense of simple memorization.

Shen Song Yang Xin Capsule Combined with Antiarrhythmic Drugs, a New Integrative Medicine Therapy, for the Treatment of Frequent Premature Ventricular Contractions (FPVC): A Meta-Analysis of Randomized Controlled Trials

Objective. To evaluate the beneficial and adverse effects of Shen Song Yang Xin Capsule (SSYX Capsule) combined with antiarrhythmic drugs for the treatment of frequent premature ventricular contractions (FPVC). Methods. Seven electronic databases were searched to retrieve any potential randomized controlled trials (RCTs) designed to evaluate the clinical efficacy of SSYX Capsule combined with Antiarrhythmic Drugs for FPVC reported in any language, with total effect for FPVC and number of ventricular premature contraction as the main outcome measure. The methodological quality of the included studies was assessed using criteria from the Cochrane Handbook for Systematic Review of Interventions, Version 5.1.0, and analysed using RevMan 5.1.0 software. Results. Sixteen RCTs of SSYX Capsule were included. The methodological quality of the trials was generally evaluated as low. The results of meta-analysis showed that SSYX Capsule combined with antiarrhythmic drugs was more effective in total effect for FPVC and number of ventricular premature contraction compared with Antiarrhythmic Drugs in patients with FPVC or FPVC complicated by other diseases. Ten of the trials reported adverse events, indicating that the safety of SSYX Capsule is still uncertain. Conclusions. There is some but weak evidence about SSYX Capsule combined with antiarrhythmic drugs appearing to be more effective in total effect for FPVC and number of ventricular premature contraction in patients with FPVC and its complications.

Relative efficacy of catheter ablation vs antiarrhythmic drugs in treating premature ventricular contractions: a single-center retrospective study

BACKGROUND

It is unknown whether radiofrequency ablation (RFA) or antiarrhythmic therapy is superior when treating patients with symptomatic premature ventricular contractions (PVCs).

OBJECTIVE

To determine the relative efficacy of RFA and antiarrhythmic drugs (AADs) on PVC burden reduction and increasing left ventricular systolic function.

METHODS

Patients with frequent PVCs (>1000/24 h) were treated either by RFA or with AADs from January 2005 through December 2010. Data from 24-hour Holter monitoring and echocardiography before and 6-12 months after treatment were compared between the 2 groups.

RESULTS

Of 510 patients identified, 215 (40%) underwent RFA and 295 (60%) received AADs. The reduction in PVC frequency was greater by RFA than with AADs (-21,799/24 h vs -8,376/24 h; P < .001). The left ventricular ejection fraction (LVEF) was increased significantly after RFA (53%-56%; P < .001) but not after AAD (52%- 52%; P = .6) therapy. Of 121 (24%) patients with reduced LVEF, 39 (32%) had LVEF normalization to 50% or greater. LVEF was restored in 25 of 53 (47%) patients in the RFA group compared with 14 of 68 (21%) patients in the AAD group (P = .003). PVC coupling interval less than 450 ms, less impaired left ventricular function, and RFA were independent predictors of LVEF normalization performed by using multivariate analysis.

CONCLUSION

RFA appears to be more effective than AADs in PVC reduction and LVEF normalization.

Quantitative localization of premature ventricular contractions using myocardial activation ECGI from the standard 12-lead electrocardiogram

BACKGROUND

The precise localization of the site of origin of a premature ventricular contractions (PVC) prior to ablation would facilitate the planning and execution of the electrophysiological procedure. Current electrocardiographic imaging (ECGI) techniques require body surface maps, a costly and complex procedure, that requires as many as 256 leads to localize the PVC origin. We developed and tested a novel myocardial activation based ECGI technique utilizing the readily available 12-lead ECG to localize the PVC origin.

METHODS

The major components of the 12-lead ECGI method are: the source model, proximity effect and spatial orientation, volume conductor, and patient specific model of the heart, lungs, and thorax as derived from magnetic resonance imaging (MRI). For the PVC origin localization, the fastest route algorithm is used on patient specific models created by newly developed morphing software. PVC localization by the 12-lead ECGI was correlated to the site of successful ablation.

RESULTS

Seven patients that underwent electrophysiological mapping and ablation of PVCs were studied. All patients (7/7) had accurate prediction of the PVC origin. However in two patients, no specific MRI was used for localization that resulted in an incorrect switch between the RV free wall and septum of the RVOT. With patient-specific models, these latter two cases would likely be localized correctly.

CONCLUSIONS

This feasibility study of a novel myocardial activation-based ECGI using only the standard 12-lead ECG shows promise to localize the origin of PVC. This ECGI method yields activation estimates of isochrones on both ventricles from which the PVC origin location is derived. This method has the capability to localize the PVC from any part of the ventricular endocardium, intra-myocardium or epicardium.