There are three major mechanical complications after acute myocardial infarction: left ventricular (LV) free-wall rupture, interventricular septum rupture, and acute mitral valve regurgitation [1]. Acute or subacute LV free-wall rupture is a “serious” and often “lethal” complication of ST elevation myocardial infarction (STEMI), reported as a common finding in patients who die from acute myocardial infarction (MI) [1, 2].

These are rare complications [3]. LV free-wall rupture after MI has an incidence of 2–4% [3]. Considering all patients who suffer acute MI, the incidence of LV pseudoaneurysm (PSA) is low (< 1%) and even lower when the patients undergo primary percutaneous coronary intervention (PCI), considering the latter as a protective factor [3].

A 66-year-old man with multiple cardiovascular risk factors; such as diabetes, hypertension, smoking and STEMI 6 years ago, who did not receive a reperfusion therapy. He consulted the ER referring atypical chest pain that began 8 days prior to his visit. He showed normal vital signs with the following relevant findings in the cardiovascular physical examination: visible and palpable double systolic apical impulse with a wide apical impulse area (4,5 cm in diameter), located in the fifth intercostal space of the left mid-clavicular line. On auscultation, an audible fourth heart sound (S4) was present. The cardiac biomarkers were negative.

We discuss the case of a 66-year-old male with a history of MI, six-years prior to consulting our hospital; that due to lack of access to a cath lab, the patient didn’t receive any reperfusion strategy. Thus, the patient only received medical treatment as an inpatient in a 2nd level hospital and the initial symptoms associated to the pseudoaneurysm were probably considered as part of the symptoms related to an acute MI.

Myocardial rupture usually occurs within the first 3–5 days after the infarction in half of the cases (early rupture) and in the first two weeks in 90% (late rupture) [4]. The clinical course varies, being one of the causes of sudden death in asymptomatic acute MI [4, 5].

The LV free-wall rupture can be complete or incomplete [6]. Complete rupture triggers hemopericardium and sudden death from cardiac tamponade, whereas incomplete rupture may occur when an organized thrombus and the pericardium seals the ventricular perforation forming a ventricular PSA [6].

LV PSA is a rare disorder but of great clinical relevance due to its high associated mortality [7]. It usually occurs after transmural myocardial infarction, being the most common cause of LV PSA [7]. They typically have a narrow neck, lacking the elements of the original ventricular wall (myocardium and endocardium) and are more often located in the posterior and lateral wall segments, in contrast with true aneurysms which are more often seen in the anterior wall and apex, they always contain myocardium in their wall and have a wide neck [7, 8].

The diagnosis of LV PSA can be difficult because patients are often either asymptomatic, or present with non-specific symptoms attributable to other causes. It can even be diagnosed incidentally. A multimodality imaging diagnostic approach can be necessary, including transthoracic/transoesophageal echocardiogram, cardiovascular magnetic resonance (CMR), chest CT, myocardial perfusion imaging (MPI) and LV angiography [4, 9].

European Society of Cardiology guidelines for the management of STEMI establish that the diagnosis is confirmed with a TTE. These guidelines consider CMR can complement the diagnosis by identifying the contained cardiac rupture and its anatomical features to guide surgical interventions [10]. In this case report, we confirmed the diagnosis with TTE and obtained complementary information with other imaging modalities like Chest CT scan and MPI. We considered the information obtained with these techniques sufficient to establish the diagnosis and to guide the surgical intervention.

Immediate surgery is the treatment of choice, because an untreated PSA has a 30 to 45% rupture risk [11]. The patient underwent surgery with a programed two-step intervention, aneurysmectomy plus CABG, as is recommended in the clinical practice guidelines [10]. In the setting of a PSA, aneurysmectomy with a pericardial patch (or other material) is recommended [10]. The mortality rates in this type of interventions are in the order of 20–75% [10]. The morphologic characteristics encountered in this particular PSA suggested chronicity; we believe that this PSA could have occurred years before the diagnosis at our hospital, hence the “petrous” consistency which made resection impossible. Regarding the surgical treatment received by the patient, there are to our knowledge no available reports that establish a recommendation with respect to a specific treatment of choice in the setting of a giant PSA with “petrous” consistency. Due to the patient’s current clinical condition, we believe that the correct treatment option was chosen.

The present case report is interesting because it is unusual to find this mechanical complication of MI. Its low incidence is probably secondary to a greater accessibility to primary PCI (which has been previously described as a protective factor). This patient didn’t receive any reperfusion therapy (fibrinolysis/PCI), before attending our Centre; therefore, he was more likely to present this potentially fatal complication. In addition, the multimodality cardiac imaging used in this case, is very illustrative of this MI “serious” mechanical complication.

When encountered, PSA requires immediate surgery because an untreated LV PSA has a high risk of rupture, leading to cardiac tamponade, shock and death. CABG plus aneurysmectomy with geometric reconstruction was considered for this patient following guideline recommendations; however in this case, only successful CABG was performed; the “petrous” consistency of the PSA made aneurysmectomy impossible to perform.

Finally, although a high mortality without surgery is reported, our patient maintains a favorable evolution two-years post CABG; he is currently in NYHA II functional class, receiving optimal medical treatment and regular follow-up visits as an outpatient in our Centre.

In conclusion, the LV free-wall rupture is a serious and often lethal complication of STEMI resulting a common finding in patients who die from acute MI. LV PSA is a rare disorder but of great clinical relevance due to the high associated mortality. The diagnosis of LV PSA can be difficult and often requires a multimodality imaging diagnostic approach. This MI “serious” mechanical complication can be prevented by primary PCI, however, when it is found, warrants surgical treatment. This particular case is atypical. The long evolution of this complication made surgical resection impossible, despite this setback, the patients’ evolution was favorable.