Left ventricular aneurysm
This patient presented with anteroseptoapical necrosis with the presence of an anteroapical aneurysmal pouch at cardiac ultrasound. Following an acute coronary syndrome, the ST-segment generally returns to the isoelectric line after about 2 weeks, while the Q-waves persist and the T-waves flatten, becoming inverted and subsequently normalize. A certain degree of elevation may persist on the long-term mainly in patients with anterior infarction, especially when the reperfusion has been incomplete or late and the sequela is transmural, or more rarely in patients with inferior infarction. In some instances, ultrasound reveals a sequela of extensive necrosis associated with the presence of an aneurysmal pouch with a narrowed wall and dyskinetic movements which can be complicated by a wall thrombus with high emboligenic risk.
The electrical characteristic of a left ventricular aneurysm has been ultimately defined by anatomo-clinical and angiographic confrontations. It comprises persistent abnormalities of ventricular repolarization associated with a sequela of necrosis. We consequently find:
- a sustained elevation remote from the initial acute coronary episode constitutes the most evocative electrical sign. There can be some chronological variability in the remission of acute electrical abnormalities and it is only legitimate to consider ectasis after a minimum of 3 weeks to 1 month. The dyskinetic aneurysmal zone cannot in itself generate a subepicardial ST-segment changes. The persistent elevation of the ST-segment may therefore originate from the surrounding tissues (paradoxical movement of the junctional tissue or muscle lesion of the tissue at the periphery of the ectasic zone because of tension and stretching exerted by the aneurysmal scar).The elevation presents certain characteristics: a) its topography corresponds to the zone of necrosis; b) it is most often observed in the precordial leads corresponding to the anterior territory; c) it is stable from one tracing to the other, without dynamic variations; d) it is most often isolated without reciprocal ST depression pattern; e) it is of variable amplitude depending on the patient but can sometimes reach 5 mm; the relationship between the amplitude of the elevation and the volume of the ectasic zone is not linear; f) it can exhibit a concave or convex upward pattern; g) the elevation generally disappears or decreases after aneurysm surgery;
- changes in the pattern of the QRS-complex along with a sequela of necrosis (Q-waves with poor R wave progression) within the same territory as the subepicardial lesion, very often associated with an intraventricular conduction disorder (parietal block indicative of the alteration of the ventricular activation sequence);
- T-waves following the elevation are often inverted and not very tall (unlike the tall T-waves observed in acute phase during a developing infarction). A low ratio between the amplitude of the T-wave and the amplitude of the preceding QRS wave favors the diagnosis of aneurysm.