Polymorphic Ventricular Tachycardia: Terminology, Mechanism, Diagnosis, and Emergency Therapy

Viskin, Sami; Chorin, Ehud; Viskin, Dana; Hochstadt, Aviram; Schwartz, Arie Lorin; Rosso, Raphaël

doi:10.1161/circulationaha.121.055783

Cited by 30 publications

(20 citation statements)

References 142 publications

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“…It's possible some patients coincidentally suffered from a ventricular tachydysrhythmia in the setting of QTc prolongation, but not frank TdP. Some of these cases have been referred to as “pseudo‐Torsade de Pointes.” 1,24 We took a conservative approach to the definition of TdP to minimize this risk. Conversely, by taking a conservative approach and constraining our initial ECG search to patients with QTc > 500 ms and HR < 60 BPM we enriched our series with the more common bradycardia‐induced TdP.…”

Section: Methodsmentioning

confidence: 99%

“…When multiple EADs combine, a premature ventricular contraction (PVC) may originate during or shortly after the T wave downslope of the preceding cardiac cycle 2 . These PVC's can initiate TdP, a reentrant polymorphic ventricular tachycardia (PVT) 1 . TdP is a rare condition but can lead to sudden cardiac death in patients with a spectrum of chronic disease burden from none to large.…”

Section: Introductionmentioning

confidence: 99%

“…Torsades de Pointes (TdP) is a life threatening polymorphic ventricular tachydysrhythmia that occurs in the setting of and is caused by QT-interval prolongation. 1 The QT interval is the ECG manifestation of the depolarization to repolarization phases of the ventricular myocardium. Heart rate corrected QT (QTc) prolongation can lead to early after depolarizations (EAD) of the ventricular myocardium.…”

Section: Introductionmentioning

confidence: 99%

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Electrocardiographic measures of repolarization heterogeneity are not predictive for Torsades de Pointes among undifferentiated patients with prolonged QTc: A case control study

Marill

Lopez

Hark

et al. 2022

Cardiovasc electrophysiol

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Introduction Torsades de Pointes (TdP) is a potentially lethal polymorphic ventricular tachydysrhythmia associated with and caused by prolonged myocardial repolarization. However, prediction of TdP is challenging. We sought to determine if electrocardiographic myocardial repolarization heterogeneity is necessary and predictive of TdP. Methods We performed a case control study of TdP at a large urban hospital. We identified cases based on a hospital center electrocardiogram (ECG) database search for tracings from 1/2005 to 6/2019 with heart rate corrected QT (QTc) > 500, QRS < 120, and heart rate (HR) < 60, and a subsequent natural language search of electronic health records for the terms: TdP, polymorphic ventricular tachycardia, sudden cardiac death, and relevant variants. Controls were drawn in a 2:1 ratio to cases from a similar pool of ECGs, and matching for QTc, heart rate, sex, and age. We abstracted historical, laboratory, and ECG data using detailed written instructions and an electronic database. We included a second blinded data abstractor to test data abstraction and manual ECG measurement reliability. We used General Electric (GE) QT Guard software for automated repolarization measurements. We compared groups using unpaired statistics. Results We included 75 cases and 150 controls. The number of current QTc prolonging medications and serum electrolytes were substantially the same between the two groups. We found no significant difference in measures of QT or T wave repolarization heterogeneity. Conclusion Electrocardiographic repolarization heterogeneity is not greater in otherwise unselected patients with QTc prolongation who suffer TdP and does not appear predictive of TdP. However, previous observations suggest specific repolarization characteristics may be useful for defined patient subgroups at risk for TdP.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Electrocardiographic measures of repolarization heterogeneity are not predictive for Torsades de Pointes among undifferentiated patients with prolonged QTc: A case control study

Marill

Lopez

Hark

et al. 2022

Cardiovasc electrophysiol

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“…A mechanism that leads to EAD occurs in the long QT syndrome [11,12], where the interval between waves Q and T of the electrocardiogram is prolonged. This interval correspond to the depolarization and repolarization of ventricular cells.…”

Section: Introductionmentioning

confidence: 99%

“…Polymorphic ventricular tachycardias, on the other hand, appear as oscillations with modulated amplitude and have a spiral with drifting or meandering core, i.e., the waves rotate around a functional core. Particularly, in torsades de pointes the oscillations appear to twist around the electrocardiogram baseline, reversing its polarity [11,12]. Polymorphic ventricular tachycardias can deteriorate to ventricular fibrillation, leading to cardiac arrest and death.…”

Section: Introductionmentioning

confidence: 99%

Cardiac Reentry Modeled by Spatiotemporal Chaos in a Coupled Map Lattice

Stenzinger,

Tragtenberg

2022

Preprint

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Arrhythmias are potentially fatal disruptions to the normal heart rhythm, but their underlying dynamics is still poorly understood. Theoretical modeling is an important tool to fill this gap. Typical studies often employ detailed multidimensional conductance-based models. We describe the cardiac muscle with a three-dimensional map-based membrane potential model in lattices. Although maps retain the biophysical behavior of cells and generate computationally efficient tissue models, few studies have used them to understand cardiac dynamics. Our study captures healthy and pathological behaviors with fewer parameters and simpler equations than conductance models. We successfully generalize results obtained previously with reaction-diffusion systems, showing how chaotic properties result in reentry, a pathological propagation of stimuli that evolves to arrhythmias with complex spatiotemporal features. The bifurcation diagram of the single cell is very similar to that obtained in a detailed conductance-based model. We find torsade de pointes, a clinical manifestation of some types of tachycardia in the electrocardiogram, using a generic sampling of the whole network during spiral waves. We also find a novel type of dynamical pattern, with wavefronts composed of synchronized cardiac plateaus and bursts. Our study provides the first in-depth look at the use of map-based models to simulate complex cardiac dynamics.

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