Intraventricular conduction defects in acute myocardial infarction. What is the influence of primary coronary angioplasty on their prognosis?

Álvaro D.B Bordalo,Armando L Bordalo-Sá,Maria José Correia,Carlos Ribeiro,A Nunes Diogo

doi:10.15761/vdt.1000146

Abstract

Intraventricular conduction defects in acute myocardial infarction. What is the influence of primary coronary angioplasty on their prognosis?

Highlights

Introduction and objectiveIn the pre-thrombolytic era, patients with a major intraventricular conduction defect (IVCD) – right bundle branch block (RBBB), left bundle branch block (LBBB), left posterior hemiblock (LPH), advanced (QRS > 105 msec) left anterior hemiblock (LAH) or left IVCD with normal axis and QRS > 115 msec – acquired during ST-segment elevation myocardial infarction (STEMI) very frequently had a poor in-hospital prognosis
Emergent coronary angioplasty (CA) significantly improved the global prognosis of acquired major IVCD but did not significantly modify the ominous prognosis of pts with STEMI complicated by LBBB or sustained RBBB, either isolated or associated with LAH; to improve the poor prognosis in these cases, primary CA should be performed within the first 2 hours of STEMI evolution
According to the different types of acute intraventricular block (IVB) considered, their prevalences were as follows: isolated LAH – 15.0 per cent globally, and 1.8 per cent for advanced LAH; isolated LPH – 1.3 per cent; isolated RBBB – 3.3 per cent; RBBB associated to LAH – 3.3 per cent; RBBB associated to LPH – 0.2 per cent; complete LBBB – 2.1 per cent; aspecific left IVB – 2.3 per cent; aspecific bilateral IVB – 0.7 per cent

Summary

Introduction

In the pre-thrombolytic era, patients (pts) with a major intraventricular conduction defect (IVCD) – right bundle branch block (RBBB), left bundle branch block (LBBB), left posterior hemiblock (LPH), advanced (QRS > 105 msec) left anterior hemiblock (LAH) or left IVCD with normal axis and QRS > 115 msec – acquired during ST-segment elevation myocardial infarction (STEMI) very frequently had a poor in-hospital prognosis. Prior to the introduction of coronary reperfusion therapies (initially the fibrinolytic treatment, and later, the mechanical reperfusion), the patients showing major IVB – that is, incomplete or complete right bundle branch block (RBBB), non-brady dependent complete left bundle branch block (LBBB) pattern, left posterior hemiblock (LPH), advanced (QRS duration > 105 msec) left anterior hemiblock (LAH), and left IVB with normal axis, non-LBBB pattern but a QRS duration of 120 msec or longer – acquired through the acute phase of myocardial infarction, frequently had a poor or very poor prognosis, especially in patients presenting with RBBB [1,2] or complete LBBB [2]. The first reports on this subject from the mechanical reperfusion era persistently revealed a significantly higher short-term mortality in STEMI patients with acute RBBB or complete LBBB [5,6,7].

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