Abstract A 62 year old man arrived in PS for typical chest pain radiating to the jugular and associated with sweating for about three hours. History of arterial hypertension and untreated dyslipidemia, family history of CVD. ECG: sinus rithm at rate of 50 bpm with first degree AVB. Inferior ST elevation in inferior leads and ST depression in V2–V3. Echocardiogram: depressed systolic function (EF 48%) in relation to hypo–akinesia of the mid–basal segments of the inferior–posterior–lateral wall. Diagnosed with STEMI inferior–posterior, was sent to the cath lab to undergo to emergency coronary angiography, with findings of non–significant atheromas on IVA and Cx. Multiple unsuccessful attempts to search for the right coronary artery and failure to visualize the aortography in two complementary projections. During the procedure hemodynamic and electrical instability, worsening angor, marked hypotension and extreme bradycardia up to complete AVB with asystole phases. Inotropics and atropine were started, which proved ineffective, and it was therefore decided to proceed with the implantation of a temporary pacemaker. During the placement, the patient presented cardiac arrest from VF (likely an irritating effect from the passage of the lead through the tricuspid) treated with effective DC–shock. Given the technical difficulties in proceeding with mechanical revascularization and given the patient‘s instability, the decision was made to postpone PCI by attempting systemic thrombolysis. Early efficacy of thrombolysis with disappearance of precordial pain, improvement of echo motion and reduction > 50% of the ST–segment elevation to the rare spontaneous QRS displayed at the transient shutdown of the temporary PM. Subsequent emergence of AF at rate of 116 bpm. Approximately 12 hours after thrombolysis: complete ST resolution in absence of Q waves. AngioTC of the coronaries was performed which showed regularl origin of Cdx from the right coronary sinus but higher up and lateralized to the left, with severe lesion in the first segment. So the patient underwent falicitated PCI with detection of ostio–proximal Cdx thrombotic lesion effectively treated with PTCA and drug–eluting stent placement with good final angiographic result. Control echo: preserved global left ventricular motion (FE 55%), hypokinesia of the basal segment of the inferior wall. The remaining stay decurred without any complications and the patient was discharged with indications for a close follow–up.