Idiopathic ventricular tachycardia detected after coronavirus disease 2019.

We present a 23-year-old woman with depression and long COVID in whom a diagnosis of idiopathic ventricular tachycardia (VT) was made. Although the relationship between idiopathic VT and long COVID remains unknown, this is the first report of idiopathic VT detected in a patient with long COVID.

Trends Favoring an Anatomical Approach to Radiofrequency Catheter Ablation of Idiopathic Ventricular Arrhythmias Originating From the Left Ventricular Summit.

BACKGROUND: Epicardial radiofrequency catheter ablation (RFCA) of idiopathic ventricular arrhythmias (VAs) originating from the left ventricular summit (LVS) is challenging because of the anatomic barriers. On the other hand, RFCA at the endocardial sites near the earliest epicardial activation site of LVS-VAs (anatomic approach) has proven successful. The evolving trends in the approaches and outcomes of RFCA of LVS-VAs at a single center were evaluated. METHODS: We studied 88 consecutive patients with idiopathic LVS-VAs at our institute from 2009 to 2019. These patients were divided into 3 periods: 2009 to 2012 (early), 2013 to 2015 (middle), and 2016 to 2019 (recent). The data were compared among the 3 periods. RESULTS: The RFCA success rate did not significantly change from the early to middle period but significantly increased from the middle to recent period (P=0.0315). The transpericardial approach usage significantly decreased over the 3 periods. The anatomic approach usage significantly increased over the 3 periods. The use of the transpericardial approach did not affect the RFCA outcomes over the 3 periods. The success rate of the anatomic RFCA tended to increase from the early to middle period and significantly increased from the middle to recent period (P=0.0412). The number of endocardial locations where RFCA was successful increased over the 3 periods. CONCLUSIONS: Over the 10-year period, the transpericardial approach became decreasingly performed, whereas the anatomic approach became increasingly performed with a satisfactory improvement in the RFCA outcomes of LVS-VAs. The anatomic RFCA became more successful by identifying more and various endocardial locations as target sites.

The relationship between epicardial adipose tissue volume on coronary computed tomography angiography and idiopathic ventricular tachycardia: a propensity score matching case-control study in Chinese population.

Background: Large epicardial adipose tissue (EAT) volume is associated with the incidence of premature ventricular beats. The relationship between EAT volume and idiopathic ventricular tachycardia (IVT) is not yet clear. We aimed to investigate the effect of EAT volume on the risk of IVT. Methods: This is a retrospective consecutive case-control study from January 2020 to September 2022. IVT patients (n=81) and control patients (n=162) undergoing coronary computed tomography angiography (CCTA) were retrospectively recruited. The patients in the control group were all hospitalized patients for different reasons, such as chest tightness, shortness of breath, chest pain, and so on. Demographic parameters and clinical characteristics of each individual were collected from the patient's medical records. We selected evaluation criteria for the conduct of a 1:1 propensity score (PS)-adjusted analysis. Multivariable logistic analysis was used to investigate risk factors for IVT. Furthermore, the impact of EAT volume on cardiac repolarization indices was assessed in IVT patients. Results: Patients with IVT had a larger EAT volume than control group patients in the unadjusted cohort. Variables with P<0.10 in the univariable analysis and important factors were included in the multivariable analysis model, including body mass index (BMI), left ventricular ejection fraction (LVEF), early peak/artial peak (E/A) ratios <1, EAT attenuation, and EAT volume (per increase 10 mL). The multivariable logistic analysis found that EAT volume [per increase 10 mL, odds ratio (OR): 1.29, 95% confidence interval (CI): 1.17-1.41, P<0.001] was an independent risk factor for IVT. EAT volume (per increase 10 mL, OR: 1.43, 95% CI: 1.25-1.64, P<0.001) independent effect was demonstrated in the PS adjusted cohort (n=57 in both groups). The area under the curve of EAT volume to predict the risk of IVT patients in the PS adjusted cohort was 0.859. The sensitivity and specificity were 86.0%, and 75.4%, respectively. Furthermore, A large EAT volume of IVT patients had a longer time in Tp-e, and Tp-e/QTc, compared with low EAT volume. Conclusions: Patients with IVT had increased EAT volume compared to control subjects. Our study revealed that large EAT volume is associated with an extended repolarization process in IVT patients. These insights are essential for understanding the mechanisms linking EAT with IVT.

Idiopathic Ventricular Tachycardia in the Presence of Triple-Vessel Coronary Artery Disease: A Case Report.

Exercise-induced ventricular tachycardia undergoes ischemia evaluation; however, it is important to identify idiopathic ventricular tachycardia in patients with concomitant coronary artery disease and radiofrequency ablations can be lifesaving. We report a case of exercise-induced right and left ventricular outflow tract ventricular tachycardia in a patient with triple vessel coronary artery disease.

Upper turnaround point in a reentry circuit of the idiopathic left posterior fascicular ventricular tachycardia.

BACKGROUND: The anatomic extent of the reentry circuit in idiopathic left posterior fascicular ventricular tachycardia (LPF-VT) is yet to be fully elucidated. We hypothesized that entrainment mapping could be used to delineate the reentry circuit of an LPF-VT, especially including the upper turnaround point. METHODS: Twenty-three consecutive LPF-VT patients (mean age, 29 ± 9 years, 18 males) were included. We performed overdrive pacing with entrainment attempts at the left bundle branch (LBB) and the left His bundle (HB) region. RESULTS: Overdrive pacing from the LBB region showed concealed fusion in all 23 patients (post-pacing interval [PPI], 322.1 ± 64.3 ms; tachycardia cycle length [TCL], 319.0 ± 61.6 ms; PPI-TCL, 3.1 ± 4.6 ms) with a long stimulus-to-QRS interval (287.9 ± 58.0 ms, approximately 90% of the TCL). Pacing from the same LBB region at a slightly faster pacing rate showed manifest fusion with antidromic conduction to the LBB and minimal in-and-out time to the LBB potential (PPI-TCL, 21.3 ± 13.7 ms). Overdrive pacing from the left HB region showed manifest fusion with a long PPI-TCL (53.9 ± 22.5 ms). CONCLUSIONS: Our pacing study results suggest that the upper turnaround point in a reentry circuit of the LPF-VT may extend to the proximal His-Purkinje conduction system near the LBB region but below the left HB region. The LPF may constitute the retrograde limb of the reentry circuit.

Artificial Intelligence-Enabled Smartwatch Used for the Detection of Idiopathic Ventricular Tachycardia: A Case Report.

Cardiovascular disease has become a huge burden to human health. Artificial intelligence (AI)-enabled smartwatches continuously monitor the heart rate, which potentially helps to diagnose unwarranted rhythm and irregularity problems such as tachycardia, bradycardia, and fibrillation. Deep learning (DL), convolutional neural networks (CNN), and support vector machines are various modalities of AI adopted in the field of cardiology extensively, starting from a single echocardiogram to cardiac imaging. Yet, the efficacy and safety of machine learning in healthcare have always raised valid questions for the manufacturers of various healthcare devices. It is thus challenging and promising to see how AI in medicine will affect human lives in tackling various medical conditions along with global threats such as pandemics. A case report on idiopathic ventricular tachycardia (VT) detected by an AI-aided smartwatch is presented in this paper.

The predictive value of Tp-Te interval, Tp-Te/QT ratio, and QRS-T angle of idiopathic ventricular tachycardia in patients with ventricular premature beats.

BACKGROUND: Identify idiopathic ventricular tachycardia in patients with ventricular premature beats was required to have effectively treatment. HYPOTHESIS: The aim of this study is to investigate the predictive value of Tp-Te interval, Tp-Te/QT ratio, and QRS-T angle of idiopathic ventricular tachycardia in patients with idiopathic ventricular premature beats. METHODS: One hundred and seventy-eight patients who had undergone premature ventricular complex/ventricular tachycardia (PVC/VT) ablation between January 1, 2020 and August 30, 2022 constituted our study population as ventricular arrhythmia group. Seventy-five healthy people were selected as control group. Patients with no episode of VT were classified as PVC group, while with any episode of VT that has the same morphology with PVC were classified as PVC with VT group. Patients in PVC with VT group were divided into two groups: nonsustained VT group (duration of any episode of VT below 30 s) and sustained VT group (duration of any episode of VT over 30 s). Tp-Te interval, Tp-Te/QT ratio and QRS-T angle were compared in groups. RESULTS: Tp-Te interval, Tp-Te/QT ratio and patients with increased QRS-T angle in PVC with VT group were higher or more than those in PVC group (p < .001). The value of combined diagnosis of these indexes was higher. Tp-Te interval was longer in the sustained VT group compared to the nonsustained VT group (p = .009). CONCLUSION: Tp-Te interval, Tp-Te/QT ratio, and QRS-T angle may have a predictive value of presence of idiopathic VT in patients with premature beats and the combined prediction of these indexes is more valuable. Tp-Te interval maybe helpful for prediction of sustained idiopathic VT.

Independent Association between Epicardial Adipose Tissue Volume and Recurrence of Idiopathic Ventricular Tachycardia after Ablation.

Background: Epicardial adipose tissue (EAT) thickness is an independent predictor for the recurrence of premature ventricular beats after ablation. However, it is unclear whether EAT volume is associated with the recurrence of idiopathic ventricular tachycardia (IVT) following ablation. This study sought to investigate the association between EAT volume and IVT recurrence following radiofrequency ablation for IVT patients. Methods: This retrospective study included 69 IVT patients undergoing computed tomography examination before ablation who underwent their first catheter ablation between 2017 and 2021. The predictive value of EAT volume for IVT recurrence following ablation was assessed. Results: During the follow-up period (median: 540 days; range: 253-929 days), 26.1% (18/69) of the patients experienced IVT recurrence. The cut-off point of EAT volume for predicting IVT recurrence was 160.30 mL, and the area under the curve (AUC) was 0.751 (95% confidence interval (CI): 0.615-0.887) by the receiver operating characteristic curve. Kaplan-Meier analysis showed that patients with larger EAT volumes had higher cumulative rates of IVT recurrence. Multivariable analysis also revealed that EAT volume (per 10 mL increase; hazard ratio (HR): 1.16, 95% CI: 1.03-1.32, p = 0.018) was independently associated with IVT recurrence. Furthermore, patients with an epicardial site of IVT had a significantly larger EAT volume than IVT patients with non-epicardial origins. Conclusions: A larger EAT volume may be associated with IVT recurrence after catheter ablation. EAT volume may be helpful for risk stratification in patients undergoing IVT ablation.

Genome-Wide Association Study for Idiopathic Ventricular Tachyarrhythmias Identifies Key Role of CCR7 and PKN2 in Calcium Homeostasis and Cardiac Rhythm Maintenance.

BACKGROUND: Idiopathic ventricular tachycardia (VT) occurs in structurally normal hearts and accounts for a significant number of all types of VT. The genome-wide association study is the most effective strategy for identifying novel genetic variants for common diseases. However, no genome-wide association study has been reported for idiopathic VT. METHODS: We conducted the first genome-wide association study for idiopathic VT in the Chinese Han population using a discovery population with 246 cases and 648 controls and a replication population with 222 cases and >4072 controls. Candidate VT genes were functionally characterized in zebrafish. Real-time RT-PCR analysis was used to determine the effects of candidate genes on expression of ion channels and regulators. Patch-clamping was used to record L-type calcium current from neonatal rat cardiomyocytes with overexpression of candidate genes. RESULTS: We identified 4 significant loci represented by rs78960694 (minor allele frequency [MAF]=5.02% in cases and 1.84% in controls; P=4.30×10-12, odds ratio [OR]=3.91) and rs2229095 (MAF=3.25% in cases and 1.63% in controls; P=1.02×10-7, OR=3.44) near and in CCR7, respectively, rs68126098 in NELL1 (MAF=40.98% in cases and 32.07% in controls; P=2.40×10-8, OR=1.53), rs2390325 between PKN2 and LMO4 (MAF=21.19% in cases and 15.12% in controls; P=1.92×10-7, OR=1.62), and rs270065 in CSMD1 (MAF=33.63% in cases and 40.25% in controls; P=9.51×10-7, OR=0.69). Note that the associations of idiopathic VT for CCR7 variant rs78960694 and NELL1 variant rs68126098 reach genome-wide significance (P<5.00×10-8). Overexpression of either PKN2 or CCR7 increased the heart rate in zebrafish, and enhanced expression of CACNA1C, RYR2, or NOS1AP in zebrafish embryos, HEK293, and AC16 cardiomyocytes. Overexpression of either PKN2 or CCR7 significantly increased L-type Ca2+ current density. CONCLUSIONS: The first genome-wide association study identifies 4 novel loci and 2 risk genes (PKN2 and CCR7) for idiopathic VT. These findings identify new molecular determinants for cardiac calcium homeostasis and rhythm maintenance and provide novel targets for diagnosis and treatment for idiopathic VT.

A Wide QRS Tachycardia with Three Distinct Left Bundle Branch Block Morphologies in a Patient with Sinus Rhythm with Left Bundle Branch Block: What Is the Mechanism?

The differential diagnosis for a wide complex tachycardia includes all causes of supraventricular tachycardia (SVT) with bundle branch block or all causes of SVT with antegrade pre-excitation by bystander involvement of any accessory pathways, myocardial or bundle brunch ventricular tachycardia, and antidromic (atriofascicular or nodofascicular/nodoventricular) and other pre-excited reciprocating tachycardias. We present a case of wide complex QRS tachycardia with a left bundle branch block QRS morphology.

Verapamil-sensitive idiopathic left ventricular tachycardia and concomitant atrioventricular nodal reentrant tachycardia.

We describe the case of a young patient with runs of repetitive monomorphic left ventricular tachycardia. He was diagnosed with verapamil-sensitive, idiopathic left ventricular tachycardia (ILVT) and underwent an electrophysiological study, in which dual atrioventricular (AV) nodal physiology was evident, with an AV nodal reentrant tachycardia (AVNRT) being easily and reproducibly induced. Both the AVNRT and the ILVT were successfully ablated using high-density electroanatomical mapping and an open-irrigation catheter. In conclusion, verapamil-sensitive ILVT might coexist with AVNRT. In case of invasive therapy, a thorough electrophysiological evaluation is mandatory to exclude or treat other co-existing reentrant supraventricular arrhythmias.

Prospective Multicenter Assessment of a New Intraprocedural Automated System for Localizing Idiopathic Ventricular Arrhythmia Origins.

OBJECTIVES: The objective of this study was to present a new system, the Automatic Arrhythmia Origin Localization (AAOL) system, which used incomplete electroanatomic mapping (EAM) for localization of idiopathic ventricular arrhythmia (IVA) origin on the patient-specific geometry of left ventricular, right ventricular, and neighboring vessels. The study assessed the accuracy of the system in localizing IVA source sites on cardiac structures where pace mapping is challenging. BACKGROUND: An intraprocedural automated site of origin localization system was previously developed to identify the origin of early left ventricular activation by using 12-lead electrocardiograms (ECGs). However, it has limitations, as it could not identify the site of origin in the right ventricle and relied on acquiring a complete EAM. METHODS: Twenty patients undergoing IVA catheter ablation had a 12-lead ECG recorded during clinical arrhythmia and during pacing at various locations identified on EAM geometries. The new system combined 3-lead (III, V2, and V6) 120-ms QRS integrals and patient-specific EAM geometry with pace mapping to predict the site of earliest ventricular activation. The predicted site was projected onto EAM geometry. RESULTS: Twenty-three IVA origin sites were clinically identified by activation mapping and/or pace mapping (8, right ventricle; 15, left ventricle, including 8 from the posteromedial papillary muscle, 2 from the aortic root, and 1 from the distal coronary sinus). The new system achieved a mean localization accuracy of 3.6 mm for the 23 mapped IVAs. CONCLUSIONS: The new intraprocedural AAOL system achieved accurate localization of IVA origin in ventricles and neighboring vessels, which could facilitate ablation procedures for patients with IVAs.

Clinical Spectrum of SCN5A Channelopathy in Children with Primary Electrical Disease and Structurally Normal Hearts.

Sodium voltage-gated channel α subunit 5 (SCN5A)-mutations may cause an array of arrhythmogenic syndromes most frequently as an autosomal dominant trait, with incomplete penetrance, variable expressivity and male predominance. In the present study, we retrospectively describe a group of Mexican patients with SCN5A-disease causing variants in whom the onset of symptoms occurred in the pediatric age range. The study included 17 patients with clinical diagnosis of primary electrical disease, at least one SCN5A pathogenic or likely pathogenic mutation and age of onset <18 years, and all available first- and second-degree relatives. Fifteen patients (88.2%) were male, and sixteen independent variants were found (twelve missense, three truncating and one complex inframe deletion/insertion). The frequency of compound heterozygosity was remarkably high (3/17, 17.6%), with early childhood onset and severe disease. Overall, 70.6% of pediatric patients presented with overlap syndrome, 11.8% with isolated sick sinus syndrome, 11.8% with isolated Brugada syndrome (BrS) and 5.9% with isolated type 3 long QT syndrome (LQTS). A total of 24/45 SCN5A mutation carriers were affected (overall penetrance 53.3%), and penetrance was higher in males (63.3%, 19 affected/30 mutation carriers) than in females (33.3%, 5 affected/15 carriers). In conclusion, pediatric patients with SCNA-disease causing variants presented mainly as overlap syndrome, with predominant loss-of-function phenotypes of sick sinus syndrome (SSS), progressive cardiac conduction disease (PCCD) and ventricular arrhythmias.

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.

Family-Based Whole Genome Sequencing Identified Novel Variants in ABCA5 Gene in a Patient with Idiopathic Ventricular Tachycardia.

Idiopathic ventricular tachycardia (IVT) is the major cause of sudden cardiac death. Patients with IVT were usually manifested without structural heart disease. In this present study, we performed family-based whole genome sequencing (WGS) and Sanger sequencing for a 5-year-old Chinese boy with IVT and all the unaffected family members in order to identify the candidate gene and disease-causing mutation underlying the disease phenotype. Results showed that a novel heterozygous single-nucleotide duplication (c.128dup) and a novel heterozygous missense (c.3328A > G) variant in ABCA5 gene were identified in the proband. The single-nucleotide duplication (c.128dupT), inherited from his father and patrilineal grandfather, leads to a frameshift which results into the formation of a truncated ABCA5 protein of 50 (p.Leu43Phefs*8) amino acids. Hence, it is a loss-of-function mutation. The missense (c.3328A > G) variant, inherited from his mother, leads to the replacement of isoleucine by valine at the position of 1110 (p.Ile1110Val) of the ABCA5 protein. Multiple sequence alignment showed that p.Ile1110 is evolutionarily conserved among several species indicating both the structural and functional significance of the p.Ile1110 residue in the wild-type ABCA5 protein. Quantitative RT-PCR showed that the ABCA5 mRNA expression levels were decreased in the proband. These two novel variants of ABCA5 gene were co-segregated well among all the members of this family. Our present study also strongly supports the importance of using family-based whole genome sequencing for identifying novel candidate genes associated with IVT.

Idiopathic Left Ventricular Tachycardia Originating in the Left Posterior Fascicle.

Ventricular tachycardias originating from the Purkinje system are the most common type of idiopathic left ventricular tachycardia. The majority if not all of the reentrant circuit involved in this type of tachycardia is formed by the Purkinje fibres of the left bundle branch, particularly the left posterior fascicle. In general, slowly conducting Purkinje fibres (P1) form the antegrade limb, and normally conducting Purkinje fibres (P2) form the retrograde limb of the reentrant circuit of the ventricular tachycardia originating from the left posterior fascicle. Elimination of the critical Purkinje elements in the reentrant circuit is the route to successful ablation. While the reentrant circuit identified by activation mapping provides the roadmap to ablation targets, comparing the difference in the His-ventricular interval during sinus rhythm and tachycardia also helps to identify the critical site in the reentrant circuit.

QRS morphology in lead V1 for the rapid localization of idiopathic ventricular arrhythmias originating from the left ventricular papillary muscles: A novel electrocardiographic criterion.

BACKGROUND: Twelve-lead electrocardiogram (ECG) criteria have been developed to identify idiopathic ventricular arrhythmias (VAs) from the left ventricular (LV) papillary muscles (PAPs), but accurate localization remains a challenge. OBJECTIVE: The purpose of this study was to develop ECG criteria for accurate localization of LV PAP VAs using lead V1 exclusively. METHODS: Consecutive patients undergoing mapping and ablation of VAs from the LV PAPs guided by intracardiac echocardiography from 2007 to 2018 were reviewed (study group). The QRS morphology in lead V1 was compared to patients with VAs with a "right bundle branch block" morphology from other LV locations (reference group). Patients with structural heart disease were excluded. RESULTS: One hundred eleven patients with LV PAP VAs (mean age 54 ± 16 years; 65% men) were identified, including 64 (55%) from the posteromedial PAP and 47 (42%) from the anterolateral PAP. The reference group included patients with VAs from the following LV locations: fascicles (n = 21), outflow tract (n = 36), ostium (n = 37), inferobasal segment (n = 12), and apex (5). PAP VAs showed 3 distinct QRS morphologies in lead V1 93% of the time: Rr (53%), R with a slurred downslope (29%), and RR (11%). Sensitivity, specificity, positive predictive value, and negative predictive value for the 3 morphologies combined are 93%, 98%, 98%, and 93%, respectively. The intrinsicoid deflection of PAP VAs in lead V1 was shorter than that of the reference group (63 ± 13 ms vs 79 ± 24 ms; P < .001). An intrinsicoid deflection time of <74 ms best differentiated the 2 groups (sensitivity 79%; specificity 87%). CONCLUSION: VAs originating from the LV PAPs manifest unique QRS morphologies in lead V1, which can aid in rapid and accurate localization.