Ventricular Repolarization Dynamicity Provides Independent Prognostic Information Toward Major Arrhythmic Events in Patients With Idiopathic Dilated Cardiomyopathy

Abstract

In patients with DCM, QT dynamicity is independently associated with the occurrence of major arrhythmic events and improves the predictive accuracy of stratifying arrhythmic risk of these patients.

Changing Characteristics and Mode of Death Associated With Chronic Heart Failure Caused by Left Ventricular Systolic Dysfunction

“…A link between inhomogeneous electric depolarization and arrhythmic death in heart failure caused by LV systolic dysfunction has been suggested. 30,31 The present data set demonstrates a significant reduction in prolonged QRS duration (Ͼ120 ms) and QTc dispersion, consistent with a favorable effect on electric remodeling and increased electric stability of the failing left ventricle. Increasing QRS width is associated with advancing age and worsening LV function, 32 whereas CRT would be expected to reduce QRS width; wider QRS intervals are also associated with slower repolarization, in the form of increasing corrected QT interval, and increased dispersion of the QT interval.…”

Beat-to-Beat Variability in Preload Unmasks Latent Risk of Torsade de Pointes in Anesthetized Chronic Atrioventricular Block Dogs

“…Pressure-volume (PV) loops were recorded in order to quantify the pacing-induced preload variability, with and without mechanical ventilation, simultaneously with LV MAP, in an additional set of 9 CAVB dogs (median 9 [7][8][9][10][11][12][13][14] weeks after AV-block). In the same experiment, the effect of SAC block by streptomycin on baseline BVR and arrhythmic response to dofetilide was tested; during pacing with alternating PQ, streptomycin was infused (40 mg/kg in 5 min i.v.…”

“…These results confirm the association between STVMAPD and proarrhythmia, and suggest involvement of the SAC in BVR in the CAVB dog. infusion: 27 vs. 4 [2][3][4][5][6][7][8][9][10][11][12][13] (P=0.07, Figure 6). However, this could not prevent an increase of STVMAPD, from 0.6±0.2 ms to 4.0±3.3 ms (P=0.006), and is similar to the value obtained in the group that received only dofetilide.…”

“…In these dogs, dofetilide infusion (0.025 mg · kg -1 · 5 min -1 ) was followed by streptomycin (40 mg · kg -1 · 5 min -1 , n=7), while in controls (n=10), only dofetilide was administered. Arrhythmia score, determined during the 15-25 min interval after the start of dofetilide administration, was significantly lower in the streptomycin-treated animals (2 [1][2][3] vs. 4 [2][3][4][5][6][7][8][9][10][11], P=0.049). Literature provides a possible role for ISAC in triggering of the ectopic beats that initiate the TdP arrhythmias; formation of early afterdepolarizations (EADs) in vivo may be a stochastic Figure 6.…”

2017 ISHNE-HRS expert consensus statement on ambulatory ECG and external cardiac monitoring/telemetry

“…Iacoviello et al (2007) found that NSVT was associated with threefold higher risk of arrhythmic events during follow-up and that prognostic value of NSVT was enhanced by a combination with low LVEF and abnormal QT dynamics. In Marburg Cardiomyopathy study (Grimm, Christ, Bach, Müller, & Maisch, 2003), NSVT evaluated alone was not associated with an increased risk of arrhythmic events; however, when combined with low LVEF, the risk was eightfold higher.…”