Complete AVB Initially Complicating STEMI in Post Percutaneous Revascularization: Case Report

Conduction disturbances complicating acute myocardial infarction with persistent ST segment elevation are common...


Introduction
Complete or third degree atrioventricular block (cAVB), defined by the complete and permanent interruption of the transmission of atrial impulses to the ventricles [1,2] is one of the early and relatively frequent complications of myocardial necrosis whose pathophysiology and the course differs depending on the seat of the infarction; indeed, AVB always shows anatomically extensive infarcts, the mortality of which from previous infarctions complicated by AVB remains considerable (> 60%) in the absence of early revascularization [3,4]. This complication, very common before the era of revascularization, occurs in the acute phase.
Their early installation in post reperfusion of an extensive anterior myocardial infarction is unprecedented and has a particular aspect which justifies our review. We report a case of complete atrioventricular block occurring initially after Percutaneous Revascularization (PR) of extensive anterior ST + (STEMI-EA).

Clinical Case
This is a 51-year-old patient, chronic active smoker and diabetic discovered in hospital, with no history; he presented with an inaugural retrosternal infarction stabbing chest pain,

Discussion
The vascularization of the cardioverter system, in particular that of the atrioventricular bundle and its branches is provided by the artery of the atrioventricular node and an anterior septal artery (usually the second). This accounts for the conduction disturbances that are observed during certain myocardial infarctions [5]. The blocks of anterior and / or septal infarctions, related to an attack of the AIV, are located low, secondary to the involvement of the 2 branches or the 3 fascicles of the bundle of His. However, this is not immediately simultaneous, hence the usual precession of bundle branch block or bifascicular, on atrioventricular block [3]. According to our research, this unprecedented case is the first patient to initially develop cAVB after PR from STEMI-EA. In all the studies reviewed, there is unanimity that the prognosis for mortality from complicated MI of cAVB is poor, whether it occurs in the acute phase before or after the PRC era. Authors who have performed studies on cAVB complicating MI, we cite UJ Gang, Hymie H, Harpaz D, Nguyen [6][7][8][9] have worked on what appear to be patients with cAVB present during the early phase of an MI even before revascularization either by thrombolysis or by PR to judge the effectiveness of the two methods on the patient's prognosis. In the course of our research, we issued opinions, possible hypotheses, which could explain, if applicable, our patient: a) Either by stenosis of the Stent with spontaneous reperfusion by fibrinolysis which allows the lysis of the fibrinoerythro-platelet clot, and the maintenance of vascular permeability [10,11] (The in situ formation of a coronary thrombus can lead to the occlusion responsible for 'an MI, followed by spontaneous lysis of the thrombus, which may explain the discovery of normal angiography [12]); which is unlikely given that the patient received a 600 mg bolus of Clopidogrel, just prior to PR, to prevent activation of platelets by inhibiting adenosine Di-phosphate; b) Or by prolonged vasospasm of the anterior interventricular artery [11][12][13][14][15][16][17][18].
In these two hypotheses, the patient would undergo a second MI in the anterior extensive with ischemia of the cardionector system. This would justify the electrical occurrence of a cAVB, then the enhancement of his STEMI in the same territory followed by cardiac arrest due to asystole (Figure 3).   [13]. The population is younger than in classic coronary patients, with a predominance of men, whose main cardiovascular risk factor incriminated in this pathology is active smoking [14]. Studies have assessed the association of clinical risk associated with factors with induction of coronary artery spasm. It emerges that smoking was a risk factor for coronary artery spasm in numerous studies [15]: this is the cardiovascular profile of our patient whose development, after recovered cardiac arrest, was marked by spontaneous recovery of his condition sinus heart rate after h.m ( Figure 6) However, the occurrence of the patient's sudden death at home, after three weeks of his discharge after returning to sinus rhythm, suggests a recurrence of the same clinical picture during his stay (Figures 4 & 5). It is believed that in the acute phase of an MI even in post revascularization, not everything is won.
However, continued clinical monitoring in a cardiology intensive care unit is the rule. We also insist on the fact that patients prone to this complication of BAVc occurring before or after percutaneous revascularization of a previous ACS ST +, should benefit from the implantation of a pacemaker in prevention of recurrence of conduction disorder and cardiac asystole, considering the very high risk of mortality [19] (Table 1).  b. Electro rhythm trained by the Electro-systolic Training Probe probe. Note: 5:00 p.m., cardiac arrest from asystole ensues requiring resuscitation by cardio thoracic massage for 10 to 15 minutes with the use of adrenaline and other drugs. The patient is then taken to the Catheterization room for a second coronary angiography by the same day team. Second coronary angiography showing a stent in place, permeable with good TIMI 3. Then installation of an Electro-systolic Training Probe by the Rhythmology team.

Conclusion
High-degree conduction disorders, such as complete atrioventricular block, are among the early complications of anterior myocardial infarction indicating a poor prognosis, the urgency of which would be immediate revascularization, as well as the initiation of instead of an electro systolic training probe or even a pacemaker. It is therefore unprecedented to see such a conduction disorder occurring, in the first place, hours after percutaneous revascularization, the causes of which are still uncertain.