Ventricular Tachycardia Publications (35327)


Ventricular Tachycardia Publications

Circ Arrhythm Electrophysiol
Circ Arrhythm Electrophysiol 2017 Jan;10(1)
From the Department of Cardiology (S.K., C.V.D., S.J.A.) and Division of Pediatric Cardiology, Department of Pediatrics (S.J.A.), Mayo Clinic College of Medicine, Rochester, MN; and Mayo Clinic Medical School, Rochester, MN (P.G.).
Rev Esp Cardiol (Engl Ed)
Rev Esp Cardiol (Engl Ed) 2017 Jan 10. Epub 2017 Jan 10.
Departamento de Cardiología y Cirugía Cardiaca, Clínica Universidad de Navarra, Pamplona, Navarra, Spain. Electronic address:
Cardiol Young
Cardiol Young 2017 Jan;27(S1):S126-S131
Children's Hospital of Orange County,University of California Irvine,Irvine, California,United States of America.
Cardiol Young
Cardiol Young 2017 Jan;27(S1):S121-S125
Interventional Electrophysiology and Pacing,University of Florida - Jacksonville/Gainesville,Jacksonville,Florida,United States of America.
Cardiol Young
Cardiol Young 2017 Jan;27(S1):S62-S67
2Heart Center, Department ofPediatric Cardiology,Phoenix Children's Hospital,University of Arizona College of Medicine-Phoenix,Phoenix, Arizona,United States of America.

The Wolff-Parkinson-White pattern refers to the electrocardiographic appearance in sinus rhythm, wherein an accessory atrioventricular pathway abbreviates the P-R interval and causes a slurring of the QRS upslope - the "delta wave". It may be asymptomatic or it may be associated with orthodromic reciprocating tachycardia; however, rarely, even in children, it is associated with sudden death due to ventricular fibrillation resulting from a rapid response by the accessory pathway to atrial fibrillation, which itself seems to result from orthodromic reciprocating tachycardia. Historically, patients at risk for sudden death were characterised by the presence of symptoms and a shortest pre- excited R-R interval during induced atrial fibrillation <250 ms. Read More

Owing to the relatively high prevalence of asymptomatic Wolff-Parkinson-White pattern and availability of catheter ablation, there has been a need to identify risk among asymptomatic patients. Recent guidelines recommend invasive evaluation for such patients where pre-excitation clearly does not disappear during exercise testing. This strategy has a high negative predictive value only. The accuracy of this approach is under continued investigation, especially in light of other considerations: Patients having intermittent pre-excitation, once thought to be at minimal risk may not be, and the role of isoproterenol in risk assessment.

Cardiol Young
Cardiol Young 2017 Jan;27(S1):S49-S56
1Department of Pediatrics,Children's Heart Centre,Division of Cardiology,British Columbia Children's Hospital,Vancouver,British Columbia,Canada.

Since the sentinel description of exercise-triggered ventricular arrhythmias in 21 children, our recognition and understanding of catecholaminergic polymorphic ventricular tachycardia has improved substantially. A variety of treatments are now available, but reaching a diagnosis before cardiac arrest remains a challenge. Most cases are related to variants in the gene encoding for ryanodine receptor-2 (RyR2), which mediates calcium-induced calcium release. Read More

Up to half of cases remain genetically elusive. The condition is presently incurable, but one basic intervention, the universal administration of β-blockers, has improved survival. In the past, implantable cardioverter-defibrillators (ICDs) were frequently implanted, especially in those with a history of cardiac arrest. Treatment limitations include under-dosing and poor compliance with β-blockers, and potentially lethal ICD-related electrical storm. Newer therapies include flecainide and sympathetic ganglionectomy. Limited data have suggested that genotype may predict phenotype in catecholaminergic polymorphic ventricular tachycardia, including a higher risk of life-threatening cardiac events in subjects with variants in the C-terminus of ryanodine receptor-2 (RyR2). At present, international efforts are underway to better understand this condition through large prospective registries. The recent publication of gene therapy in an animal model of the recessive form of the disease highlights the importance of improving our understanding of the genetic underpinnings of the disease.

Cardiol Young
Cardiol Young 2017 Jan;27(S1):S43-S48
Department of Pediatric Cardiology,Cleveland Clinic Main Campus,Cleveland,Ohio,United States of America.

Ventricular tachycardia (VT) radiofrequency ablation has been associated with reduced VT recurrence and mortality, although it is typically not considered among New York Heart Association class IV (NYHA IV) heart failure patients. We compared characteristics and VT radiofrequency ablation outcomes of those with and without NYHA IV in the International VT Ablation Center Collaboration.
NYHA II-IV patients undergoing VT radiofrequency ablation at 12 international centers were included. Read More

Clinical variables, VT recurrence, and mortality were analyzed by NYHA IV status using Kaplan-Meier analysis and Cox proportional hazard models. There were significant differences between NYHA IV (n=111) and NYHA II and III (n=1254) patients: NYHA IV had lower left ventricular ejection fraction; more had diabetes mellitus, kidney disease, cardiac resynchronization implantable cardioverter-defibrillator, and VT storm despite greater antiarrhythmic drug use (P<0.01). NYHA IV subjects required more hemodynamic support, were inducible for more and slower VTs, and were less likely to undergo final programmed stimulation. There was no significant difference in acute complications. In-hospital deaths, recurrent VT, and 1-year mortality were higher in the NYHA IV group, in the context of greater baseline comorbidities. Importantly, NYHA IV patients without recurrent VT had similar survival compared with NYHA II and III patients with recurrent VT (68% versus 73%). Early VT recurrence (≤30 days) was significantly associated with mortality, especially in NYHA IV patients.
Despite greater baseline comorbidities, VT radiofrequency ablation can be safely performed among NYHA IV patients. Early VT recurrence is significantly associated with subsequent mortality regardless of NYHA status. Elimination of recurrent VT in NYHA IV patients may reduce mortality to a level comparable to NYHA II and III with arrhythmia recurrence.

Whether the distribution of scar in arrhythmogenic right ventricular cardiomyopathy (ARVC) plays a role in predicting different types of ventricular arrhythmias is unknown. This study aimed to investigate the prognostic value of scar distribution in patients with ARVC.
We studied 80 consecutive ARVC patients (46 men, mean age 47 ± 15 years) who underwent an electrophysiological study with ablation. Read More

Thirty-four patients receive both endocardial and epicardial mapping. Abnormal endocardial substrates and epicardial substrates were characterized. Three groups were defined according to the epicardial and endocardial scar gradient (<10%: transmural, 10-20%: intermediate, >20%: horizontal, as groups 1, 2, and 3, respectively). Sinus rhythm electrograms underwent a Hilbert-Huang spectral analysis and were displayed as 3D Simultaneous Amplitude Frequency Electrogram Transformation (SAFE-T) maps, which represented the arrhythmogenic potentials. The baseline characteristics were similar between the three groups. Group 3 patients had a higher incidence of fatal ventricular arrhythmias requiring defibrillation and cardiac arrest during the initial presentation despite having fewer premature ventricular complexes. A larger area of arrhythmogenic potentials in the epicardium was observed in patients with horizontal scar. The epicardial-endocardial scar gradient was independently associated with the occurrence of fatal ventricular arrhythmias after a multivariate adjustment. The total, ventricular tachycardia, and VF recurrent rates were higher in Group 3 during 38 ± 21 months of follow-up.
For ARVC, the epicardial substrate that extended in the horizontal plane rather than transmurally provided the arrhythmogenic substrate for a fatal ventricular arrhythmia circuit.

Various ryanodine receptor 2 (RyR2) point mutations cause catecholamine-induced polymorphic ventricular tachycardia (CPVT), a life-threatening arrhythmia evoked by diastolic intracellular Ca(2+) release dysfunction. These mutations occur in essential regions of RyR2 that regulate Ca(2+) release. The molecular dysfunction caused by CPVT-associated RyR2 mutations as well as the functional consequences remain unresolved. Read More

Here, we study the most severe CPVT-associated RyR2 mutation (K4750Q) known to date. We define the molecular and cellular dysfunction generated by this mutation and detail how it alters RyR2 function, using Ca(2+) imaging, ryanodine binding, and single-channel recordings. HEK293 cells and cardiac HL-1 cells expressing RyR2-K4750Q show greatly enhanced spontaneous Ca(2+) oscillations. An endoplasmic reticulum-targeted Ca(2+) sensor, R-CEPIA1er, revealed that RyR2-K4750Q mediates excessive diastolic Ca(2+) leak, which dramatically reduces luminal [Ca(2+)]. We further show that the K4750Q mutation causes three RyR2 defects: hypersensitization to activation by cytosolic Ca(2+), loss of cytosolic Ca(2+)/Mg(2+)-mediated inactivation, and hypersensitization to luminal Ca(2+) activation. These defects combine to kinetically stabilize RyR2-K4750Q openings, thus explaining the extensive diastolic Ca(2+) leak from the sarcoplasmic reticulum, frequent Ca(2+) waves, and severe CPVT phenotype. As the multiple concurrent defects are induced by a single point mutation, the K4750 residue likely resides at a critical structural point at which cytosolic and luminal RyR2 control input converge.