Evolution of Ventricular Tachycardia and Its Electrophysiological Substrate Early After Myocardial Infarction

Hsieh, C.; Chia, E.; Huang, Kaimin; Lu, Juntang; Barry, Michael A.; Pouliopoulos, Jim; Ross, David L.; Thomas, Stuart P.; Kovoor, Pramesh

doi:10.1161/circep.113.000348

Cited by 18 publications

(17 citation statements)

References 25 publications

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“…In an ovine model, these re-entrant circuits of VT have been seen to form and stabilize within the first week after infarction. 45 Hsieh et al 45 demonstrated that inducibility of VT day 8 after infarction was concordant with inducibility of VT at day 100 in 100% of sheep. In this study, the earliest activation sites of the VTs, the cycle length, and the relationship to areas of myocardial injury were similar between the day 8 and chronic periods.…”

Section: Substrate For Re-entrant Tachycardiamentioning

confidence: 99%

“…V ovčím modelu byly pozorovány vznik a stabilizace těchto reentry okruhů KT v prvním týdnu po infarktu. 45 Hsieh a spol. 45 prokázali, že indukovatelnost KT osmý den po infarktu se shodovala s indukovatelností KT ve stý den u 100 % ovcí.…”

Section: Substrát Reentry Tachykardiíunclassified

“…45 Hsieh a spol. 45 prokázali, že indukovatelnost KT osmý den po infarktu se shodovala s indukovatelností KT ve stý den u 100 % ovcí. V uvedené studii byly místa nejčasnější aktivace KT, délka cyklu i vztah k oblastem poškození myokardu stejné osmý den i v chronickém období.…”

Section: Substrát Reentry Tachykardiíunclassified

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Sudden Cardiac Death Early After Myocardial Infarction

2014

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The issue of SCD primary prevention early after MI remains unresolved. The focus is now firmly centered on the elucidation of risk stratification tests that effectively select patients at high risk of SCD who benefit from early ICD implantation. Zaman and Kovoor Primary Prevention of SCD Early After MI 2429A summary of major risk stratification tests currently used to identify patients at high risk of SCD is given in Table 2. LV DysfunctionImpaired LVEF, one of the most powerful predictors of survival, 64 has been shown to identify patients who derive a mortality benefit from an ICD when implanted predominantly in the remote period after MI. 16,65 However, there are major concerns with the use of LVEF alone as a risk stratifier to guide ICD implantation. One such concern is the low specificity of LVEF for selecting patients who experience arrhythmic versus nonarrhythmic death. In the MADIT II trial, the use of LVEF ≤30% alone to stratify patients for an ICD resulted in relatively small absolute improvement in mortality with low therapeutic efficiency (15-17 defibrillators per life saved). 66 Another concern is the sensitivity of LVEF, given that a large proportion of SCDs still occur in patients with preserved LV function. VALIANT demonstrated that, although the risk of SCD is greatest in patients with severe dysfunction (LVEF ≤30%), almost half of all sudden deaths occur in patients with a higher ejection fraction (LVEF, 31%-40%). 5 The use of LVEF as a risk stratification tool has been tested in the early post-MI stage in the DINAMIT and IRIS trials, which selected patients with LVEF ≤35% and ≤40%, respectively, and failed to show a benefit of early ICD implantation. 12,17 The major limitation with the use of an early LVEF cutoff is the phenomenon of myocardial stunning with variable and unpredictable recovery of LV function after MI. This is especially relevant in the contemporary era of primary PCI for STEMI. Of STEMI patients with LVEF ≤40% at day 3, 24% will improve to have an LVEF >40% at 6 months with a mean 6% relative improvement. 67 Hence, although LV function will invariably be incorporated into risk stratification models for the prevention of SCD, it is clear that other tests are required to adequately select high-risk patients early after MI. RV DysfunctionAlthough impaired LV function has been studied extensively as a predictor of mortality and arrhythmic death, RV dysfunction has been largely overlooked. We know from the VALIANT study that almost 50% of arrhythmic deaths occur in patients with a preserved LVEF.5 RV involvement in inferior MI has been shown to be a predictor of morbidity and mortality, with a higher rate of serious arrhythmias in patients with inferior MI and RV dysfunction. 68,69 In addition, RV dysfunction has been correlated with increased inducibility of VT at EPS. 70 Although there is no current evidence to support the role of early RV assessment to guide ICD implantation, these findings highlight the inadequacy of LVEF alone as a risk stratification tool for the prevention...

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Section: Substrate For Re-entrant Tachycardiamentioning

confidence: 99%

Section: Substrát Reentry Tachykardiíunclassified

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Sudden Cardiac Death Early After Myocardial Infarction

2014

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“…9 In addition, animal experiments revealed early formation of arrhythmogenic substrate after induced myocardial infarction and suggested better outcomes after immediate ablation. 10,11 We hypothesized that the arrhythmia substrate evolves in the time, partially driven by the VT itself. Therefore, we aimed to determine whether CA in earlier stages of ventricular remodeling may improve the outcomes, compared with VT ablation performed as a treatment of last resort in patients with advanced stage structural heart disease.…”

Section: Clinical Perspective On P 1151mentioning

confidence: 99%

Early Referral for Ablation of Scar-Related Ventricular Tachycardia Is Associated With Improved Acute and Long-Term Outcomes

Dinov

Arya

Bertagnolli

et al. 2014

Circ: Arrhythmia and Electrophysiology

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Background— The effects of time to referral for catheter ablation (CA) of scar-related ventricular tachycardia (VT) on acute success, VT recurrence, and cardiac mortality are unclear. Methods and Results— We investigated 300 patients after CA of sustained VT. CA was performed within 30 days after the first documented VT in 75 (25%) patients (group 1), between 1 month and 1 year in 84 (28%) patients (group 2), and >1 year after the first VT occurrence in 141 (47%) patients (group 3). The end points were noninducibility of any VT after CA (acute success), VT recurrence and cardiac mortality after 2 years. Acute success was achieved in 66 (88%) patients in group 1, 68 (81%) in group 2, and in 99 (70.2%) in group 3 ( P =0.008). During the 2-year follow-up period, VT recurred in 28 (37.3%) patients in group 1, 52 (61.9%) patients in group 2, and 91 (64.5%) patients in group 3 ( P <0.0001). Recurrence-free survival was higher in group 1, as compared with group 2 (hazard ratio [HR], 1.85; P =0.009) and group 3 (HR, 2.04; P =0.001). No survival difference was observed between groups 1 and 2 (HR, 0.85; P =0.68) and groups 1 and 3 (HR, 1.13; P =0.73). β-blocker therapy, VT of ischemic origin, and complete success were associated with VT-free survival. VT recurrence (HR, 1.91; P =0.037) predicted cardiac mortality. Conclusions— CA of scar-related VT performed within 30 days after the first documented VT was associated with improved acute and long-term success. VT recurrence, but not the early referral for CA, was associated with cardiovascular mortality.

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“…4 Ovine studies conducted at our institution have suggested that post-MI substrate for ventricular tachycardia develops within the first week and remains stable into the chronic phase. 5 Our intention in using an early LVEF cutoff, with the knowledge that it would improve, was to assess a larger population during the early high-risk period but to restrict ICD implantation through the use of EPS.…”

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confidence: 99%