Is myocardial repolarization duration associated with repolarization heterogeneity?

Marill, Keith A.; Dorsey, Pat; Holmes, Anthony A.; Muthal, Ketaki; Miller, Emily S.; Xue, Joel

doi:10.1111/anec.12519

Cited by 4 publications

(3 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Heterogeneity of repolarization could facilitate variable PVC conduction including unidirectional conduction block leading to reentrant TdP. However, our previous work suggests duration of the depolarized phase as measured by the corrected J‐to‐T peak interval (JTpkc) is not generally associated with instantaneous electrocardiographic repolarization heterogeneity as measured by the T wave peak to end interval (TpTe) 7 …”

Section: Introductionmentioning

confidence: 94%

“…However, our previous work suggests duration of the depolarized phase as measured by the corrected J-to-T peak interval (JTpkc) is not generally associated with instantaneous electrocardiographic repolarization heterogeneity as measured by the T wave peak to end interval (TpTe). 7 If increased repolarization instability exists in patients who develop TdP, then the ECG T wave manifestation could be a useful marker to predict increased risk of TdP in patients with QTc prolongation. However, this has not been studied in an undifferentiated patient sample.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

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

Self Cite

View full text Add to dashboard Cite

show abstract

“…Nevertheless, it is still unclear if T-wave properties are more influenced by one of these two conditions, or if both equally contribute to the electrocardiographic alterations of ventricular recovery. Accordingly, the performance of state-of-the-art ECG markers of T-wave has been questioned in clinics, due to their inability to identify vulnerable substrates and reliably distinguish between healthy and diseased subjects ( Malik et al, 2000 ; Van Huysduynen et al, 2005 ; Smetana et al, 2011 ; Marill et al, 2018 ). Since each ECG electrode summarizes the integrated electrical activity over the entire heart, spatial properties of the cardiac generator are lost, and it was shown that features derived from such a low number of electrodes are unlikely to reflect regional changes in myocardial repolarization ( Burnes et al, 2001 ).…”

Section: Introductionmentioning

confidence: 99%

Body Surface Mapping of Ventricular Repolarization Heterogeneity: An Ex-vivo Multiparameter Study

et al. 2020

View full text Add to dashboard Cite

Background Increased heterogeneity of ventricular repolarization is associated with life-threatening arrhythmia and sudden cardiac death (SCD). T-wave analysis through body surface potential mapping (BSPM) is a promising tool for risk stratification, but the clinical effectiveness of current electrocardiographic indices is still unclear, with limited experimental validation. This study aims to investigate performance of non-invasive state-of-the-art and novel T-wave markers for repolarization dispersion in an ex vivo model. Methods Langendorff-perfused pig hearts ( N = 7) were suspended in a human-shaped 256-electrode torso tank. Tank potentials were recorded during sinus rhythm before and after introducing repolarization inhomogeneities through local perfusion with dofetilide and/or pinacidil. Drug-induced repolarization gradients were investigated from BSPMs at different experiment phases. Dispersion of electrical recovery was quantified by duration parameters, i.e., the time interval between the peak and the offset of T-wave (T PEAK -T END ) and QT interval, and variability over time and electrodes was also assessed. The degree of T-wave symmetry to the peak was quantified by the ratio between the terminal and initial portions of T-wave area ( Asy ). Morphological variability between left and right BSPM electrodes was measured by dynamic time warping (DTW). Finally, T-wave organization was assessed by the complexity of repolarization index (CR), i.e., the amount of energy non-preserved by the dominant eigenvector computed by principal component analysis (PCA), and the error between each multilead T-wave and its 3D PCA approximation (NMSE). Body surface indices were compared with global measures of epicardial dispersion of repolarization, and with local gradients between adjacent ventricular sites. Results After drug intervention, both regional and global repolarization heterogeneity were significantly enhanced. On the body surface, T PEAK -T END was significantly prolonged and less stable in time in all experiments, while QT interval showed higher variability across the interventions in terms of duration and spatial dispersion. The rising slope of the repolarization profile was steeper, and T-waves were more asymmetric than at baseline. Interventricular shape dissimilarity was enhanced by repolarization gradients according to DTW. Organized T-wave patterns were associated with abnormal repolarization, and they were properly described by the first principal components. Conclusion Repolarization heterogeneity significantly affects T-wave properties, and can be non-invasively captured by BSPM-based metrics.

show abstract

Cytochrome P450 Inhibition

2020

Human Drug Metabolism

View full text Add to dashboard Cite

Is myocardial repolarization duration associated with repolarization heterogeneity?

Abstract: Repolarization duration as measured by JTpkc is not positively associated with dispersion of repolarization as measured by TpTe or QTd. Dispersion of repolarization may not be a critical mechanistic link between QTc prolongation and TdP.

Cited by 4 publications

References 21 publications

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

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

Body Surface Mapping of Ventricular Repolarization Heterogeneity: An Ex-vivo Multiparameter Study

Cytochrome P450 Inhibition

Contact Info

Product

Resources

About