Clinical significance of ventricular tachycardia (3 beats or longer) detected during ambulatory monitoring after myocardial infarction.

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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“…94,95 As a consequence, NSVT was one of the prerequisites for entry in the late post-MI ICD trials conducted in the 1990s.…”

Section: Nonsustained Vtmentioning

confidence: 99%

“…V době před zavedením primární PCI bylo prokázáno, že nesetrvalá komorová tachykardie (NSKT) představuje nezávislý rizikový faktor mortality a NSS po IM, 94 …”

Section: Metody Stratifi Kace Rizika V čAsné Primární Prevenci Nssunclassified

Sudden Cardiac Death Early After Myocardial Infarction

2014

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“…Recent data suggest that patients with spontaneous sustained VT in whom the VT becomes noninducible in response to drugs have significant risk of recurrence if drugs are stopped. 1 The other major limitation of this study is, as described above, the fact that therapy was not administered in a randomized, controlled fashion. However, as previously noted, the analysis has sought to limit potential sources of bias, and our findings do suggest that therapy guided by the results of electrophysiologic testing may result in significantly improved outcome compared with empiric therapy.…”

Section: Discussionmentioning

confidence: 99%

Nonsustained ventricular tachycardia in patients with coronary artery disease: role of electrophysiologic study.

et al. 1987

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Sixty-two consecutive patients with chronic coronary artery disease referred for evaluation of nonsustained ventricular tachycardia (VT) underwent electrophysiologic studies. Sustained VT was induced by one to three ventricular extrastimuli in 28 patients (45%). Therapy was guided by the results of electrophysiologic testing in 44 patients: 19 patients without inducible sustained VT received no antiarrhythmic therapy, and 25 patients with inducible sustained or symptomatic nonsustained VT received therapy guided by the results of electrophysiologic studies. The results of electrophysiologic studies were ignored by physicians for a second group of 18 patients: four had inducible sustained VT but received no antiarrhythmic therapy, and 14 had inducible sustained or nonsustained VT and received antiarrhythmic therapy not guided by results of electrophysiologic testing. After a mean follow-up period of 28 months, 11 patients had died suddenly. Seven of the 11 patients who died suddenly had inducible sustained VT. Three of 44 patients in the group receiving therapy guided by electrophysiologic studies died suddenly versus eight of 18 in the group receiving therapy not guided by electrophysiologic studies (p = .001). Only one of 19 patients without inducible sustained VT who were not treated experienced sudden death. Two of four patients with inducible sustained VT who did not receive antiarrhythmic therapy died suddenly. Multivariate analysis of the relationship of induced arrhythmias, left ventricular ejection fraction, site of myocardial infarction, history of syncope, or type of antiarrhythmic therapy to outcome revealed a greater than twofold increased risk for sudden cardiac death in patients whose therapy was not guided by results of electrophysiologic study. We conclude that patients with coronary artery disease and nonsustained VT who are asymptomatic and are without inducible sustained VT have a relatively low probability of sudden death and do not require antiarrhythmic therapy. Patients with inducible sustained VT are at a significantly increased risk for sudden cardiac death, and in this group therapy that prevents induction of sustained VT is associated with a lower rate of sudden cardiac death than empiric therapy.

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“…Patients exhibiting complex ventricular arrhythmias are significantly more likely to have higher frequencies of VPBs and patients with increased frequency of VPBs are more likely to experience complex ventricular arrhythmias, such as ventricular tachycardia (VT) (24). Furthermore, CHD patients with more complex ventricular ectopy tend to show greater overall levels of VPBs and are at higher risk for mortality, especially in the presence of MI (25). We found that individuals experiencing repetitive VPBs also experience greater levels of psychological stress, but that state and trait anxiety were not elevated in this subset of patients.…”

Section: Discussionmentioning

confidence: 99%