#IVCD WITH LBBB TRIAL#

This allows a dominant (faster rhythmic) cell to lead the way in the depolarizations.

When a cell depolarizes, it becomes refractory (silent), immune to a subsequent depolarization until it re-polarizes in preparation for the next depolarization. In this way, an impulse can travel along a path. The lower rate of induced ventricular tachycardia in patients with LVH may be related to fewer myocardial infarctions (substrate for reentrant arrhythmias).' They also suggest that the 'proarrhythmia related to LVH may occur through the development of nonreentrant arrhythmias secondary to early afterdepolarizations.What Is a Bundle Branch Block? Electrical Conduction in the HeartĪll of the cells of the heart have a negative charge and have a property called automaticity–the capability to spontaneously generate a rhythmic impulse of depolarization–an electrical change that can propagate to the next cell and begin depolarization there. The authors hypothesized that the differences in baseline characteristics between patients with and without LVH, namely, that LVH patients had a lower EF and a lower rate of induced VT, but fewer MIs, suggests that 'LVH may be associated with the myopathic process in many patients with coronary artery disease. Zimetbaum and colleagues found that LVH on baseline ECG was associated with a 35% increased risk of arrhythmic death. In contrast, evidence of LVH was the only ECG abnormality that was a significant predictor of arrhythmic, but not total mortality. RBBB was not found to be predictive of arrhythmic or total mortality and left anterior hemiblock was only associated with an increased risk of total mortality, not arrhythmic mortality. The authors note however, that the hazard ratios for both IVCD and LBBB were similar between the 2 modes of death and were therefore, not predictive of one mode of death over another. Overall, the presence of IVCD was associated with a 44% increased risk in arrhythmic death and a 47% increased risk in total mortality and LBBB was associated with a 49% and 61% increased risk, respectively. LVH Only ECG Abnormality Predictive of Arrhythmic Death, Independent of Total MortalityĪfter adjusting for multiple covariates, including those listed in the table above, investigators found that LBBB or IVCD was predictive of both arrhythmic and total mortality.

Baseline Characteristics: Patients With and Without LVH and With and Without LBBB or IVCDĪCE = angiotensin-converting enzyme CHF = congestive heart failure EF = ejection fraction IVCD = intraventricular conduction delay LBBB = left bundle branch block LVH = left ventricular hypertrophy MI = myocardial infarction VT = ventricular tachycardia In addition, patients without the ECG abnormalities were more likely to be treated with standard medical therapy (with the exception of angiotensin-converting enzyme inhibitors). Interestingly, patients with LVH had a lower incidence of myocardial infarctions (MIs) and less induced sustained VT than patients without LVH whereas patients with LBBB or IVCD had a higher incidence of remote MIs (and fewer revascularizations) vs patients without either abnormality. For instance, patients with either LVH or LBBB or IVCD tended to be older, with lower EFs, and a higher incidence of congestive heart failure (CHF) compared with their counterparts who did not have the respective ECG abnormalities (Table). Left anterior hemiblock and atrial fibrillation were observed in 12% and 8% of patients, respectively.īaseline clinical characteristics differed significantly between patients with and without LVH and between patients with and without LBBB or IVCD, respectively. The authors reported that LVH was observed in 46% of patients, IVCD in 17%, LBBB in 8%, and right bundle branch block (RBBB) in 5%.

In the overall MUSTT study, the use of EP-guided antiarrhythmic therapy led to an absolute reduction of 7% and a relative risk reduction of 27% in the risk of arrhythmic or total mortality after 5 years of follow-up and the benefit was 'due solely to defibrillators not antiarrhythmic drugs.' In addition, patients who did not have an inducible arrhythmia during EP study, but who met all other enrollment criteria were followed in a registry. MUSTT patients in whom sustained VT was inducible during EP study were randomized to either EP-guided therapy, including both antiarrhythmic therapy and the use of ICDs or to medical therapy without specific antiarrhythmic treatment.

#IVCD WITH LBBB TRIAL#

MUSTT was a randomized controlled trial designed to determine whether electrophysiologically (EP)-guided antiarrhythmic therapy would reduce the risk of arrhythmic and all-cause mortality in patients with coronary artery disease, nonsustained ventricular tachycardia (VT induced during EP study), and left ventricular dysfunction (ejection fraction ≤ 40%).

Ivcd with lbbb