Radiofrequency catheter ablation of idiopathic right ventricular outflow tract arrhythmias

Electrical and Structural Insights into Right Ventricular Outflow Tract Arrhythmogenesis

The right ventricular outflow tract (RVOT) is the major origin of ventricular arrhythmias, including premature ventricular contractions, idiopathic ventricular arrhythmias, Brugada syndrome, torsade de pointes, long QT syndrome, and arrhythmogenic right ventricular cardiomyopathy. The RVOT has distinct developmental origins and cellular characteristics and a complex myocardial architecture with high shear wall stress, which may lead to its high vulnerability to arrhythmogenesis. RVOT myocytes are vulnerable to intracellular sodium and calcium overload due to calcium handling protein modulation, enhanced CaMKII activity, ryanodine receptor phosphorylation, and a higher cAMP level activated by predisposing factors or pathological conditions. A reduction in Cx43 and Scn5a expression may lead to electrical uncoupling in RVOT. The purpose of this review is to update the current understanding of the cellular and molecular mechanisms of RVOT arrhythmogenesis.

Idiopathic Ventricular Tachycardia

Idiopathic ventricular tachycardia (VT) is an important cause of morbidity and less commonly, mortality in patients with structurally normal hearts. Appropriate diagnosis and management are predicated on an understanding of the mechanism, relevant cardiac anatomy, and associated ECG signatures. Catheter ablation is a viable strategy to adequately treat and potentially provide a cure in patients that are intolerant to medications or when these are ineffective. In this review, we discuss special approaches and considerations for effective and safe ablation of VT arising from the right ventricular outflow tract, left ventricular outflow tract, left ventricular fascicles, papillary muscles, and moderator band.

The value of QRS onset of the outflow tract PVC in V1 and V2 leads recorded in fourth, third, and second intercostal spaces to differentiate main origins of premature ventricular contraction-A prospective cohort study

Background

Electrocardiography (ECG) is now proposed as a simple and cost-effective tool to determine the location of arrhythmias before ablation. We aimed to examine the value of the QRS onset of outflow tract PVC in V1 and V2 leads recorded in fourth, third, and second intercostal spaces to differentiate two main origins for premature ventricular contraction (PVC) including right ventricular outflow tract (RVOT) and left ventricular outflow tract (LVOT).

Methods

In this prospective cohort study, a total of 58 patients were studied, from whom a surface ECG was obtained using V1 and V2 leads in the fourth, third, and second intercostal spaces. ECG and Electrophysiology studie (EPS) data were then recorded and compared to determine the sensitivity and specificity of QRS onset in locating arrhythmias. The reciever operating characterictic (ROC) curve analysis was applied to test diagnostic performance.

Results

Based on the time of PVC initiation in each of the V1 and V2 leads in the fourth intercostal space, if PVC is recorded earlier in the V1 lead, its source in 95.8% of the patients is RVOT and if PVC preceded the V2 lead, 70.59% of the patients had PVC from LVOT. Comparing of QRS onset in V1 and V2 leadsrecorded from third% and and second intercostal spaces had considerable sensitivity and specificity to determine the origin of the outflow tract PVC (81.82 and 94.12%, respectively).

Conclusion

Simultaneous recording of outflow tract PVCs from second third and fourth intercostal spaces and comparing their onset can determine the left and right outflow tract PVCs with high sensitivity and specificity.

Epicardial Adipose Tissue Thickness is Higher in Right Ventricular Outflow Tract Tachycardia

Introduction: Idiopathic ventricular arrhythmias, which occur in the absence of structural heart disease, are commonly originating from the outflow tract, and 80% of the them arise from the right ventricle. Epicardial adipose tissue (EAT), which originates from the splanchnopleuric mesoderm, has been shown to be an important source of inflammatory mediators and plays an important role in cardiac autonomic function by epicardial ganglionated plexuses. EAT may potentially contribute to the pathophysiology of idiopathic right ventricular outflow tract (RVOT) tachycardia by different mechanisms. In this study, we aimed to investigate the relationship between EAT thickness and RVOT tachycardia. Methods: This study included 55 patients (32 male, 23 female) with RVOT tachycardia and 60 control subjects (38 male, 22 female). Patients who had more than three consecutive ventricular beats over 100 bpm with specific morphological features on the electrocardiogram (ECG) were diagnosed with RVOT tachycardia. EAT thickness was measured by transthoracic echocardiography. Results: EAT thickness was significantly higher in the RVOT tachycardia group (p <0.05). Ejection fraction (EF), and the thickness of the posterior wall of the left ventricle and of the interventricular septum were significantly lower, and left ventricular end-diastolic diameter, left ventricular end-systolic diameter, and left atrial diameter were significantly higher in patients who had RVOT tachycardia compared to normal subjects (p <0.05). Conclusion: Patients who were diagnosed with RVOT tachycardia had increased EAT thickness compared to normal subjects. The underlying mechanism of the condition could be mechanical, metabolic, infiltrative, or autonomic effects of the EAT.

Cardiac magnetic resonance imaging in right ventricular outflow tract arrhythmia: a retrospective analysis from a tertiary care centre in South India

INTRODUCTION

Arrhythmia arising from right ventricular outflow tract (RVOT) is the most common cause of idiopathic ventricular arrhythmia. Previous studies involving cardiac magnetic resonance imaging (MRI) in these patients are known to show abnormalities in up to 60% of patients.

METHODOLOGY

This was a retrospective descriptive analysis of patients having idiopathic RVOT arrhythmia who underwent cardiac MRI between January 2010 and December 2020. Clinical and demographic details were recorded from the electronic medical records and cardiac MRI of all patients were reviewed.

RESULTS

Among 214 patients with RVOT arrhythmia, 64 underwent cardiac MRI. A total of 41 patients, who did not have any abnormality on baseline echocardiogram were included in the study. There was male preponderance (56.1%), with median age of 43 years. About 43.9% had syncope. Twenty-four-hour Holter study revealed a premature ventricular complex (PVC) burden of 26.3 ± 11.7%. MRI showed structural abnormalities in 51.2% of patients, which commonly included RV sacculations and aneurysms. Late gadolinium enhancement (LGE) was seen in six patients, which was mostly seen in RV free wall. Right ventricular (RV) systolic dysfunction was evident in 29.3%. About 9.8% fulfilled the criteria for arrhythmogenic RV cardiomyopathy (ARVC). Out of 23 patients with baseline abnormalities on ECHO, 87% had structural abnormalities on MRI, and 43.5% fulfilled the criteria for ARVC.

CONCLUSIONS

Additional imaging by cardiac MRI helps to identify structural abnormalities in 51.2% of patients with RVOT arrhythmias, even with normal baseline echocardiogram and electrocardiogram (ECG). It is useful tool to rule out ARVC in this subset of patients, and can help in increasing the diagnostic yield in the early stages.

Prospective use of ablation index for the ablation of right ventricle outflow tract premature ventricular contractions: a proof of concept study

AIMS

Radiofrequency catheter ablation (RFCA) represents an effective option for idiopathic premature ventricular contractions (PVCs) treatment. Ablation Index (AI) is a novel ablation marker incorporating RF power, contact force, and time of delivery into a single weighted formula. Data regarding AI-guided PVCs RFCA are currently lacking. Aim of the study was to compare AI-guided and standard RFCA outcomes in patients with PVCs originating from the right ventricle outflow tract (RVOT).

METHODS AND RESULTS

Consecutive patients undergoing AI-guided RFCA of RVOT idiopathic PVCs were prospectively enrolled. Radiofrequency catheter ablation was performed following per-protocol target cut-offs of AI, depending on targeted area (RVOT free wall AI cut-off: 590; RVOT septum AI cut-off: 610). A multi-centre cohort of propensity-matched (age, sex, ejection fraction, and PVC site) patients undergoing standard PVCs RFCA was used as a comparator. Sixty AI-guided patients (44.2 ± 18.0 years old, 58% male, left ventricular ejection fraction 56.2 ± 3.8%) were enrolled; 34 (57%) were ablated in RVOT septum and 26 (43%) patients in the RVOT free wall area. Propensity match with 60 non-AI-guided patients was performed. Acute outcomes and complications resulted comparable. At 6 months, arrhythmic recurrence was more common in non-AI-guided patients whether in general (28% vs. 7% P = 0.003) or by ablated area (RVOT free wall: 27% vs. 4%, P = 0.06; RVOT septum 29% vs. 9% P = 0.05). Ablation Index guidance was associated with improved survival from arrhythmic recurrence [overall odds ratio 6.61 (1.95-22.35), P = 0.001; RVOT septum 5.99 (1.21-29.65), P = 0.028; RVOT free wall 11.86 (1.12-124.78), P = 0.039].

CONCLUSION

Ablation Index-guidance in idiopathic PVCs ablation was associated with better arrhythmic outcomes at 6 months of follow-up.

Mapping strategies for premature ventricular contractions-activation, voltage, and/or pace map

A high premature ventricular contraction (PVC) burden is associated with an increase in cardiovascular mortality and may become clinically apparent through palpitations, reduced physical capacity or PVC-induced cardiomyopathy. Catheter ablation has been shown to be a more effective tool to treat patients with a high PVC burden than medical therapy alone. Current recommendations list catheter ablation as a class I option in patients with symptomatic idiopathic outflow tract PVCs as well as in patients with suspected PVC-induced cardiomyopathy. Careful planning is necessary to maximize efficiency and outcome of the ablation procedure. Prediction of the most likely PVC origin by studying the 12-lead electrocardiogram (ECG) is important. A high burden of spontaneous PVCs is associated with a better outcome during and after the procedure; pharmacological provocation can be performed. Developments in high density mapping systems have greatly advanced accuracy and efficiency of arrhythmia mapping in recent years. Different systems are now available that allow the simultaneous use and integration of different mapping information in an automated manner. Voltage mapping, activation mapping and pace mapping are used in clinical practice today. Activation mapping is used to visualize the area of earliest activation. While it is a very accurate tool, it relies on a high burden of spontaneous PVCs. Pace mapping aims to find the target area by means of stimulation and comparison of paced QRS complexes with the clinical PVC. Today, mostly a combination of both methods is used to maximize procedure outcome and efficiency. While voltage mapping plays a primary role in the mapping of substrate-based sustained arrhythmias in patients with underlying structural heart disease, activation and pace mapping are the methods of choice for PVC mapping.

Contact-force monitoring increases accuracy of right ventricular voltage mapping avoiding “false scar” detection in patients with no evidence of structural heart disease

Purpose

Electroanatomical mapping (EAM) could increase cardiac magnetic resonance imaging (CMR) sensitivity in detecting ventricular scar. Possible bias may be scar over-estimation due to inadequate tissue contact. Aim of the study is to evaluate contact-force monitoring influence during EAM, in patients with idiopathic right ventricular arrhythmias.

Methods

20 pts (13 M; 43 ± 12 y) with idiopathic right ventricular outflow tract (RVOT) arrhythmias and no structural abnormalities were submitted to Smarttouch catheter Carto3 EAM. Native maps included points collected without considering contact-force. EAM scar was defined as area ≥1 cm² including at least 3 adjacent points with signal amplitude (bipolar <0.5 mV, unipolar 3,5 mV), surrounded by low-voltage border zone. EAM were re-evaluated offline, removing points collected with contact force <5 g. Finally, contact force-corrected maps were compared to the native ones.

Results

An EAM was created for each patient (345 ± 85 points). After removing poor contact points, a mean of 149 ± 60 points was collected. The percentage of false scar, collected during contact force blinded mapping compared to total volume, was 6.0 ± 5.2% for bipolar scar and 7.1 ± 5.9% for unipolar scar, respectively. No EAM scar was present after poor contact points removal. Right ventricular areas analysis revealed a greater number of points with contact force < 5 g acquired in free wall, where reduced mean bipolar and unipolar voltage were recorded.

Conclusions

To date this is the first work conducted on structurally normal hearts in which contact-force significantly increases EAM accuracy, avoiding “false scar” related to non-adequate contact between catheter and tissue.

Management of cardiac conduction abnormalities and arrhythmia in aircrew

Cardiovascular diseasesⁱ are the most common cause of loss of flying licence globally, and cardiac arrhythmia is the main disqualifier in a substantial proportion of aircrew. Aircrewⁱⁱ often operate within a demanding physiological environment, that potentially includes exposure to sustained acceleration (usually resulting in a positive gravitational force, from head to feet (+Gz)) in high performance aircraft. Aeromedical assessment is complicated further when trying to discriminate between benign and potentially significant rhythm abnormalities in aircrew, many of whom are young and fit, have a resultant high vagal tone, and among whom underlying cardiac disease has a low prevalence. In cases where a significant underlying aetiology is plausible, extensive investigation is often required and where appropriate should include review by an electrophysiologist. The decision regarding restriction of flying activity will be dependent on several factors including the underlying arrhythmia, associated pathology, risk of incapacitation and/or distraction, the type of aircraft operated, and the specific flight or mission criticality of the role performed by the individual aircrew.

A novel ECG criterion to differentiate left from right ventricular outflow tract premature complex

Objectives. Catheter ablation is an effective method in the treatment of idiopathic ventricular arrhythmias. The mapping methods used for predicting the original site of arrhythmias are difficult to use and time-consuming. Consequently, developing methods using surface ECG for guiding the location is important. Here, we have tested a new ECG criterion to differentiate the left from the right ventricular originated complexes (PVCs) or tachycardias (VTs). Designs. Sixty patients with idiopathic PVC or VT who had undergone a successful radiofrequency catheter ablation (RFA) of arrhythmia were enrolled. The surface ECG during sinus rhythm and arrhythmia was analyzed. Initial r wave Surface Area (ISA) index was measured by multiplying the R wave duration in milliseconds by the R wave amplitude in terms of millivolt in V1 or V2 leads. Results. Thirty-seven patients with right ventricular (RVOT) and 23 with left ventricular outflow tract (LVOT) originated VT or PVC were enrolled. The ISA index was significantly greater in LVOT-VT/PVC compared to RVOTs (63.6 ± 78.9 vs. 8.3 ± 7.3, p < .001). With a cut off value of ≥15, the index could differentiate a left from right arrhythmia with 94.6% specificity and 78.2% sensitivity (Area on the curve, 0.81; p < .001). Compared to other previously reported indices, ISA is the most specific one. Conclusion. ISA index can serve as a very useful ECG criterion for differentiating a LVOT- from RVOT-originated VTs or PVCs.

Clinical efficacy of open-irrigated electrode cooled with half-normal saline for initially failed radiofrequency ablation of idiopathic outflow tract ventricular arrhythmias

BACKGROUND

Acute failure of radiofrequency ablation (RFA) of ventricular arrhythmias (VAs) occur in 10%-20% of patients and is partly attributed to inadequate lesion depth acquired with standard ablation protocols. Half-normal saline (HNS)-irrigation is a promising strategy to improve the success rate of VA ablation.

OBJECTIVE

This study investigated the efficacy of HNS-irrigated ablation after a failed standard plain normal saline solution (PNSS)-irrigated ablation on idiopathic outflow tract ventricular arrhythmia (OT-VA).

METHOD

This is a prospective observational study of consecutive patients undergoing RFA of idiopathic OT-VA comparing the efficacy of additional HNS-irrigated ablation for failed standard PNSS-irrigated ablation. Acute failure was defined as persistence of spontaneous VA or persistent inducibility of the clinical VA.

RESULTS

Out of 160 OT-VA cases (51 ± 15-year-old, 62 males), 31 underwent HNS irrigation after a failed standard PNSS-irrigated ablation. The HNS group had a significantly longer procedure time (60.06 ± 43.83 vs 37.51 ± 33.40 minutes; P = .013) and higher radiation exposure (31.45 ± 20.24 vs 17.22 ± 15.25 minutes; P = .001) than the PNSS group but provided an additional acute success in 21 of 31 (67.7%) patients. Over a follow-up duration of 7.8 ± 4.6 months, 24 recurrences were identified, including 8 (25.8%) in the HNS and 16 (12.4%) in the PNSS group, with lower freedom from recurrence in the HNS group (log rank P = .009). No major complication was observed.

CONCLUSION

HNS-irrigated ablation after failed standard PNSS-irrigated ablation is safe and additionally improves acute ablation success by 67.7% for idiopathic OT-VA but with a higher rate of recurrence on follow-up. Whether the application of HNS as initial irrigant could result in better outcome requires further investigation.

Late fractionated potentials in catheter ablation for right ventricular outflow tract ventricular arrhythmias

BACKGROUND

Endocardial late fractionated potentials during sinus rhythm mapping may reflect abnormal "subendocardial" substrates associated with right ventricular outflow tract (RVOT) ventricular arrhythmias (VAs). The aim of this study was to explore the clinical outcomes of catheter ablation guided by these late fractionated potentials for RVOT VAs in patients without structural heart disease.

METHODS

From January 2016 to March 2018, 28 patients underwent catheter ablation for RVOT premature ventricular contractions (PVCs) or ventricular tachycardia (VT), guided by the EnSite NavX or Velocity V5.0 three-dimensional mapping system (Abbott, St. Paul, MN, USA). Among them, 10 patients (35.7%) were found to have endocardial late fractionated potentials during sinus rhythm mapping (Group 1). Group 2 was composed of 18 patients in whom no endocardial late fractionated potentials were seen. The burden of VAs, acute procedural success, and 3-month clinical outcomes were analyzed.

RESULTS

The average duration of late fractionated potentials after the end of QRS during sinus rhythm mapping in group 1 was 45.00 ± 17.15 ms. Baseline demographics and morphology and burden of PVCs were similarly distributed between both groups. Group 1 had higher acute procedural success compared to group 2 (100% vs 66.7%; P = .039). Moreover, at 3-month follow-up, group 1 had lower total PVCs (49 (1-5986) versus 4316 (1-23231); P = .048), PVC burden (0% (0-5.9) vs 4.3% (0-18.9); P = .055), and higher clinical success (100% vs 55.6%; P = .025) compared to group 2.

CONCLUSION

The identification and elimination of endocardial late fractionated potentials during sinus rhythm mapping could improve the acute success and short-term outcomes of ablation for RVOT VAs.

Ventricular Arrhythmias in the Patient with a Structurally Normal Heart

Ventricular arrhythmias (VAs) are among the most common cardiac rhythm disturbances encountered in clinical practice. Patients presenting with frequent ventricular ectopy or sustained ventricular tachycardia represent a challenging and worrisome clinical scenario for many practitioners because of concerning symptoms, frequent associated acute hemodynamic compromise, and the adverse prognostic implications inherent to these cases. While an underlying structural or functional cardiac abnormality, metabolic derangement, or medication toxicity is often readily apparent, many patients have no obvious underlying condition, despite a comprehensive diagnostic evaluation. Such patients are diagnosed as having an idiopathic VA, which is a label with specific implications regarding arrhythmia origin, prognosis, and potential for pharmacologic and invasive management. Further, a subset of patients with otherwise benign idiopathic ventricular ectopy can present with polymorphic ventricular tachycardia and ventricular fibrillation, adding a layer of complexity to a clinical syndrome previously felt to have a benign clinical course. Thus, this review seeks to highlight the most common types of idiopathic VAs with a focus on their prognostic implications, underlying electrophysiologic mechanisms, unique electrocardiographic signatures, and considerations for invasive electrophysiologic study and catheter ablation. We further address some of the data regarding idiopathic ventricular fibrillation with respect to the heterogeneous nature of this diagnosis.

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.

Voltage combined with pace mapping is simple and effective for ablation of noninducible premature ventricular contractions originating from the right ventricular outflow tract

BACKGROUND

Premature ventricular contractions (PVCs) from the right ventricular outflow tract (RVOT) can resist conventional mapping strategies. Studies regarding optimal mapping and ablation methods for patients with noninducible RVOT-PVCs are limited. We retrospectively evaluated the efficacy and safety of a novel mapping strategy for these cases: voltage mapping combined with pace mapping.

HYPOTHESIS

METHODS: We retrospectively included symptomatic patients (n = 148; 76 males; age, 44.5 ± 1.4 years) with drug-refractory PVCs originating from the RVOT, who underwent radiofrequency catheter ablation (RFCA), and stratified them as Group 1 and Group 2. Group 1 patients had noninducible RVOT-PVCs, determined after programmed stimulation, burst pacing, and isoproterenol infusion (n = 21; 12 males; age, 39.5 ± 10.8 years). Group 2 patients had inducible PVCs. Group 1 patients were subjected to voltage mapping combined with pace mapping; Group 2 underwent conventional mapping. In all patients prior to RFCA, detailed 3-dimensional electroanatomic voltage maps of the RVOT were obtained during sinus rhythm using the CARTO system.

RESULTS

Patients from both groups had similar success and complication rates associated with the RFCA. In Group 2, 89% (113/127) experienced the earliest and the successful ablation points in the voltage transitional zone. During the follow-up (36 ± 8 months), patients from both groups suffered similar rates of PVC relapse (2/21 and 7/127, respectively; P = 0.826).

CONCLUSIONS

Voltage mapping combined with pace mapping is effective and safe for patients with noninducible RVOT-PVCs determined by conventional methods.

Effectiveness of Radiofrequency Catheter Ablation of Outflow Tract Ventricular Arrhythmias in Children and Adolescents

Outflow tract ventricular arrhythmias (OTVAs) are common in children; however, experience is limited on their radiofrequency catheter ablation (RFCA). The purpose of this study was to assess the outcomes of mapping and ablation of pediatric OTVAs and to evaluate the role of ECG algorithms in distinguishing the origin of OTVAs. We compared retrospectively collected single-center data on 92 consecutive pediatric patients (58 male; age, 8.2 ± 2.9 [range 3.6-18] years) who underwent RFCA for OTVAs from 2009 to 2015. Two independent and blinded observers analyzed ECG data. Of these children, 69 (75 %) were of RVOT origin. RFCA was given up in 1 case, and the acute success rate was 92.3 % (84/91), the 1-year follow-up recurrence rate was 8.3 % (7/84) and the complications of the procedure were 2.2 % (2/92). And 3D versus 2D mapping-guided RFCA was associated with significantly (p < 0.05) higher acute success rate (96.1 % [49/51] vs. 87.5 % [35/40]), and lower X-ray exposure (742.5 ± 323.1 vs. 1432.3 ± 605.5 mGy cm²) and 1-year recurrence rate (4.1 % [2/49] vs. 14.3 % [5/35]). The positive predictive value of four types of ECG algorithms used in adults for LVOT origin was only 47.7-65.4 %. In these cases, four identified as RVOT origin and two identified as LVOT origin by ECG underwent successful ablation on the other side of outflow tract finally. And these six children who underwent successful RFCA in both sides of outflow tract had no follow-up recurrence. OTVAs in children originate mostly from RVOT. RFCA can be used for ablation of pediatric OTVAs effectively and safely. In some cases, successful RFCA should be ablated in both sides of outflow tract. ECG-based prediction of OTVA origin as used in adults is limited in children.

Radiofrequency ablation of metastatic chondrosarcoma-associated refractory ventricular tachycardia originating from the right ventricular outflow tract: A case report and literature review

Ventricular tachycardia (VT) and premature contraction originating from the right ventricular outflow tract (RVOT) usually appear in healthy individuals. Radiofrequency ablation (RFA) is highly effective at resolving this type of arrhythmia. Refractory VT of RVOT is uncommon and occasionally results from cardiac metastasis of extraskeletal mesenchymal chondrosarcomas (ESMC). ESMC is a rare malignant tumor arising from soft tissues. The current study presents the case of a 25-year-old male with severe VT arising from RVOT due to metastasis of an ESMC that originally occurred in the retroperitoneum. The diagnosis was confirmed following echocardiography and cardiac magnetic resonance. VT was eventually eliminated by RFA, and during the 8-month follow-up period the patient did not complain of any palpitations. Holter monitoring confirmed the absence of recurrence.

Right Ventricular Outflow Tract Arrhythmias: Benign Or Early Stage Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia?

Ventricular arrhythmias (VAs) arising from the right ventricular outflow tract (RVOT) are a common and heterogeneous entity. Idiopathic right ventricular arrhythmias (IdioVAs) are generally benign, with excellent ablation outcomes and long-term arrhythmia-free survival, and must be distinguished from other conditions associated with VAs arising from the right ventricle: the differential diagnosis with arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is therefore crucial because VAs are one of the most important causes of sudden cardiac death (SCD) in young individuals even with early stage of the disease. Radiofrequency catheter ablation (RFCA) is a current option for the treatment of VAs but important differences must be considered in terms of indication, purposes and procedural strategies in the treatment of the two conditions. In this review, we comprehensively discuss clinical and electrophysiological features, diagnostic and therapeutic techniques in a compared analysis of these two entities.

Treatment Or Cure Of Right Ventricular Outflow Tract Tachycardia

Right ventricular outflow tract (RVOT) ventricular tachycardias (VT) occur in the absence of structural heart disease and are called idiopathic ventricular arrhythmias. These arrhythmias are thought to be produced by adenosine-sensitive, cyclic AMP mediated, triggered activity and are commonly observed in adolescents and young adults. In the ECG, they appear with a wide QRS complex, a left bundle branch block morphology and, usually, an inferior QRS axis. In the last few years, there has been an increasing number of reports suggesting the possibility of a curative treatment of RVOT VT by means of catheter ablation. This paper reviews the rate of cure of such arrhythmias by discussing the effects of catheter ablation on symptoms, arrhythmia detection, possibility of induction, and short- and long-term follow-up studies.

Endocavitary structures in the outflow tract: anatomy and electrophysiology of the conus papillary muscles

Catheter ablation is an increasingly used and successful treatment choice for right ventricular outflow tract (RVOT) arrhythmias. While the role of endocavitary structures and the regional morphology of the ventricular inflow tract and the right atrium as a cause for difficulty with successful ablation are well described, similar issues within the RVOT are not well understood. It is also not commonly appreciated that one of the papillary muscles is located within the proximal RVOT. We report 3 patients in which ventricular arrhythmia was targeted and ablated in the conus papillary muscle. The anatomic features, potential role of the fascicular conduction system, and unique challenges with mapping arrhythmia arising from this structure are discussed.