Experimental drugs for supraventricular tachycardia: an analysis of early phase clinical trials.

INTRODUCTION: Supraventricular tachycardias (SVT) are a diverse group of commonly encountered arrhythmias arising at or above the atrioventricular (AV) node. Conventional anti-arrhythmic medications are restricted by extensive side-effect profiles and limited efficacy. Catheter ablation has emerged as a first-line therapy for many arrhythmias but is not a suitable option for all patients. This has prompted the exploration of novel pharmacological approaches targeting specific molecular mechanisms of SVT. AREAS COVERED: This review article aims to summarize recent advancements in pharmacological therapeutics for SVT and their clinical implications. The understanding of molecular mechanisms underlying these arrhythmias, particularly atrial fibrillation, has opened up new possibilities for targeted interventions. Beyond the manipulation of ion channels and membrane potentials, pharmacotherapy now focuses on upstream targets such as inflammation, oxidative stress, and structural remodeling. This review strives to provide a comprehensive overview of recent advancements in pharmacological therapeutics directed at the management of SVT. We begin by providing a brief summary of the mechanisms and management of commonly encountered SVT before delving into individual agents, which in turn are stratified based on their molecular treatment targets. EXPERT OPINION: The evolving landscape of pharmacologic therapy offers hope for more personalized and tailored interventions in the management of SVT.

PET-Driven, Voltage-Guided Atrial Endomyocardial Biopsy Clinches the Diagnosis of Cardiac Sarcoidosis.

Endomyocardial biopsy (EMB) is used in diagnosing infiltrative and other suspected cardiomyopathies. We present a case in which positron emission tomography- and electroanatomic mapping-guided EMB of the atrial septum confirmed the diagnosis of cardiac sarcoidosis in a patient with negative findings on ventricular and lymph node biopsy. (Level of Difficulty: Advanced.).

Alcohol Ablation for Ventricular Tachycardia.

Catheter-based radiofrequency (RF) ablation is an effective, well-established therapy for ventricular tachycardia (VT). However, a large number of patients still have recurrences, particularly those with substrates arising from intramural locations that are inaccessible through endo- or epicardial catheter approaches. Several unconventional ablation techniques have been proposed to treat RF-refractory VT, including transarterial coronary ethanol ablation and retrograde coronary venous ethanol ablation. We review the evidence regarding the mechanisms, procedural aspects, and alcohol ablation outcomes for ventricular arrhythmias.

Venous anatomy of the left ventricular summit: Therapeutic implications for ethanol infusion.

BACKGROUND: Venous ethanol ablation (VEA) is effective for treatment of left ventricular (LV) summit (LVS) arrhythmias. The LVS venous anatomy is poorly understood and has inconsistent nomenclature. OBJECTIVE: The purpose of this study was to delineate the LVS venous anatomy by selective venography and 3-dimensional (3D) mapping during VEA and by venous-phase coronary computed tomographic angiography (vCTA). METHODS: We analyzed (1) LVS venograms and 3D maps of 53 patients undergoing VEA; and (2) 3D reconstructions of 52 vCTAs, tracing LVS veins. RESULTS: Angiography identified the following LVS veins: (1) LV annular branch of the great cardiac vein (GCV) (19/53); (2) septal (rightward) branches of the anterior ventricular vein (AIV) (53/53); and (3) diagonal branches of the AIV (51/53). Collateral connections between LVS veins and outflow, conus, and retroaortic veins were common. VEA was delivered to target arrhythmias in 38 of 53 septal, 6 of 53 annular, and 2 of 53 diagonal veins. vCTA identified LVS veins (range 1-5) in a similar distribution. GCV-AIV transition could either form an angle close to the left main artery bifurcation (n = 16; 88° ± 13°) or cut diagonally (n = 36; 133°±12°) (P ≤.001). Twenty-one patients had LV annular vein. In 28 patients only septal LVS veins were visualized in vCTA, in 2 patients only diagonal veins and in 22 patients both septal and diagonal veins were seen. In 39 patients the LVS veins reached the outflow tracts and their vicinity. CONCLUSION: We provide a systematic atlas and nomenclature of LVS veins related to arrhythmogenic substrates. vCTA can be useful for noninvasive evaluation of LVS veins before ethanol ablation.

Intramural Venous Ethanol Infusion for Refractory Ventricular Arrhythmias: Outcomes of a Multicenter Experience.

OBJECTIVES: The aim of this study was to assess the long-term efficacy and outcomes of retrograde venous ethanol ablation in treating ventricular arrhythmias (VAs). BACKGROUND: Retrograde coronary venous ethanol ablation (RCVEA) can be effective for radiofrequency ablation (RFA)-refractory VAs, particularly those arising in the LV summit (LVS). METHODS: Patients with drug and RFA-refractory VAs were considered for RCVEA after RF failure attempts. Intramural coronary veins (tributaries of the great cardiac, anterior interventricular, lateral cardiac, posterolateral, and middle cardiac) were mapped using an angioplasty wire. Ethanol infusion was delivered in veins with appropriate signals. RESULTS: Of 63 patients (age 63 ± 14 years; 60% men) with VAs (71% extrasystole, 29% ventricular tachycardia, 76% LVS origin), RCVEA was performed in 56 patients who had suitable vein branches. These were defined as those amenable to cannulation and with intramural signals that preceded those mapped in the epicardium or endocardium and had better matching pace maps or entrainment responses. Seven patients had no suitable veins and underwent RFA. In 38 of 56 (68%) patients, the VAs were successfully terminated exclusively with ethanol infusion. In 17 of 56 (30%) patients, successful ablation was achieved using ethanol with adjunctive RFA in the vicinity of the infused vein due to acute recurrence or ethanol-induced change in VA morphology. Overall, isolated or adjuvant RCVEA was successful in 55 of 56 (98%) patients. At 1-year follow-up, 77% of patients were free of recurrent arrhythmias. Procedural complications included 2 venous dissections that led to pericardial effusions. CONCLUSIONS: RCVEA offers a significant long-term effective treatment for patients with drug and RF-refractory VAs.

Double-balloon technique for retrograde venous ethanol ablation of ventricular arrhythmias in the absence of suitable intramural veins.

BACKGROUND: Venous ethanol infusion via an occlusive balloon has been used as a bailout approach to treat ablation-refractory ventricular arrhythmias (VAs). Unfavorable venous anatomy (lack of intramural veins at the targeted site or collateral vein-ethanol shunting) limits its efficacy. Blocking collateral flow with a second balloon may optimize myocardial ethanol delivery. OBJECTIVE: The purpose of this study was to validate the "double-balloon" approach to enhance ethanol delivery in cases of unfavorable venous anatomy. METHODS: Eight patients referred after failed ablations (3 left ventricular [LV] summit, 5 scar-related ventricular tachycardia) underwent endocardial mapping and additional radiofrequency ablation without VA resolution. Coronary veins were mapped using a multipolar catheter or wire, and selective venograms were obtained. The double balloon was used when (1) distal collateral branches shunted flow away from the targeted region; (2) the target vein had optimal signals only proximally; or (3) a large vein was targeted that had multiple branches for a large area of interest. RESULTS: Acute successful ethanol infusion myocardial delivery and resolution of VA was accomplished using the posterolateral LV veins (n = 2 patients, 3 procedures), lateral LV vein (n = 1), apical anterior interventricular vein (AIV; n = 1), middle cardiac vein (n = 1), and septal branches of the AIV (n = 3). At median follow-up of 313.5 days, 2 patients experienced recurrence. CONCLUSION: The double-balloon technique can enhance ethanol delivery to target isolated vein segments, block collateral flow, or target extensive areas, and can expand the utility of venous ethanol for treatment of VAs.

The SYNTAX II Score Predicts Mortality at 4 Years in Patients Undergoing Percutaneous Coronary Intervention.

BACKGROUND: Short-term outcome after percutaneous coronary intervention (PCI) has improved dramatically, but the association between clinical or angiographic characteristics and long-term outcome remains less well described. The SYNTAX (Synergy Between PCI With TAXUS and Cardiac Surgery) II score has been designed to overcome the limitations of the purely angiographic SYNTAX I score by including clinical parameters and comorbidities. It has not been tested extensively in "real-world" PCI patients, outside of randomized clinical studies. METHODS AND RESULTS: We identified unique patients undergoing PCI between January 1, 2011 and January 24, 2013 and followed for at least 60 days. We calculated the SYNTAX I and II scores for each patient and collected data at longest follow-up available for vital status, recurrent PCI, systolic heart failure, stroke, or Q-wave myocardial infarction. Cox proportional hazards regression was used to assess independent predictors of mortality. There were 831 patients followed for a mean of 4 years. The average age was 66 ± 10 years. Nearly 40% were women and 50% had diabetes mellitus. The mean follow-up interval was 4 years, during which 42 patients died (Kaplan-Meier rate, 4.3% [IQR, 3.0-6.2%]). The PCI-SYNTAX II score was significantly higher in patients who died than in survivors (43 ± 12 vs 32 ± 12, respectively; P<.001). The SYNTAX II score was the only variable associated with death at a mean follow-up of 4 years (hazard ratio per 1 point, 1.05 [95% confidence interval, 1.03-1.08]; P<.001). CONCLUSION: The SYNTAX II score, incorporating angiographic and clinical parameters, is a useful tool for risk stratification and prediction of 4-year mortality in "real-world" patients.

Transcatheter Aortic Valve Replacement in Type B Aortic Dissection.

Transcatheter aortic valve replacement (TAVR) has become an acceptable alternative to surgical aortic valve replacement in high-risk and inoperable patients. Several technical and anatomical considerations can increase the complexity and risk of the procedure, and therefore are considered as contraindications to TAVR. Patients with significant aortic disease such as aortic dissection are not usually considered for TAVR due to risk of aortic rupture or retrograde extension of the dissection. Herein is presented a report of the first successful TAVR in a patient with extensive type B dissection.