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Puzzle 2008 04 014 Answer: Difference between revisions
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Ischaemia-induced bifascicular block, defined as RBBB along with left anterior (or posterior) fascicular block, has been associated with a 30% excessrisk of complete heart block and should therefore be regarded as ‘bad news’. Additional prolongation of the PR interval, known as incomplete trifascicular block, is associated with imminent high-degree AV block and temporary or permanent pacing used to be recommended in these circumstances in the days prior toprimary PCI.<cite>Hindman</cite><cite>Antman</cite><cite>Gregoratos</cite> | Ischaemia-induced bifascicular block, defined as RBBB along with left anterior (or posterior) fascicular block, has been associated with a 30% excessrisk of complete heart block and should therefore be regarded as ‘bad news’. Additional prolongation of the PR interval, known as incomplete trifascicular block, is associated with imminent high-degree AV block and temporary or permanent pacing used to be recommended in these circumstances in the days prior toprimary PCI.<cite>Hindman</cite><cite>Antman</cite><cite>Gregoratos</cite> | ||
In the pre thrombolytic era, in-hospitalmortality in these patients could be as high as 80%,which was mainly related to an extensive loss offunctioning myocardium.<cite>Hindman2</cite> In an emergency situation, a brief evaluation of theECG depicted in figure 1B could lead to the mis-diagnosis of a multifascicular conduction block causedby acute occlusion of the LAD artery. Nevertheless,and in contrary to the ECG in figure 1A, a normal Pwave or other forms of atrial pacemaker activity areabsent in this recording. Finally, the ECG recorded justprior to emergency coronary angiography (figure 2)shows both electrocardiographic appearances. We | In the pre thrombolytic era, in-hospitalmortality in these patients could be as high as 80%,which was mainly related to an extensive loss offunctioning myocardium.<cite>Hindman2</cite> In an emergency situation, a brief evaluation of theECG depicted in figure 1B could lead to the mis-diagnosis of a multifascicular conduction block causedby acute occlusion of the LAD artery. Nevertheless,and in contrary to the ECG in figure 1A, a normal Pwave or other forms of atrial pacemaker activity areabsent in this recording. Finally, the ECG recorded justprior to emergency coronary angiography (figure 2)shows both electrocardiographic appearances. We see the transition from the regular ventricular rhythm intosinus rhythm with subsequent disappearance of RBBB configuration and left anterior fascicular block. | ||
In conclusion, it is most likely that an | In conclusion, it is most likely that an intermittent accelerated idioventricular rhythm (AIVR) originating from the left posterior fascicle caused the widened QRS complex rhythm that competes with sinus rhythm. A second, less plausible explanation would be that the atrioventricular node or bundle of His were intermittently acting as the dominant pacemaker, accompanied by ischaemia-induced conduction disturbance of theright bundle branch and left anterior fascicle, which would be an alarming sign of severe ischaemia affecting an extensive part of the myocardium. The emergency coronary angiography revealed an occlusion of the proximal LAD artery, which was successfully treated with primary percutaneous coronary intervention (PCI). | ||
==References== | ==References== | ||