Situs inversus totalis is a rare congenital condition in which the thoracic and abdominal organs are transposed in a mirror-image fashion, compared to their normal anatomy (situs solitus). This condition presents itself with a prevalence of 1:10,000 and is more frequent in males. The incidence of acute coronary syndromes in this condition is presumed to be similar to that in the general population. Situs inversus may be challenging for the attending cardiologist in the acute setting of myocardial infarction, particularly if previously unknown. Because of the rarity of the condition, interventional cardiologists are seldomly trained to coronary interventions in the setting of situs inversus.
A 55-year-old male was referred with suspected acute coronary syndrome due to sudden onset of chest pain. Electrocardiogram (ECG) at admission displayed ST-segment elevation on right precordial leads (V2R to V5R), thus suggesting right ventricular infarction (Figure 1A).
Immediate coronary angiography was performed. Here, first positioning of the guidewire showed the aortic arch bending towards the right side, suggesting organ inversion (Figure 1B). Levocardiography performed in 30° left anterior oblique (LAO) projection revealed evidence of anterior myocardial infarction by anterior wall hypokinesia with impaired ventricular function. Selective coronary angiograms were performed with standard 6F diagnostic catheters in inverted technique, mirroring all angiographic projections and rotating the catheters during coronary intubation in the opposite direction. A Judkins R4 catheter was used for the left-sided right coronary artery (RCA) and an internal mammary artery (IMA) catheter for a second steep ostium of the left-sided RCA. The right-sided left coronary artery (LCA) was imaged with a Judkins L5 catheter, showing proximal thrombotic occlusion of a dominant ramus interventricularis anterior (RIVA) (Figures 1C-1D, asterisk and Figure 1G; * = RIVA, # = ramus circumflexus (RCx), + = RCA).
Recanalization and percutaneous transluminal coronary angioplasty (PTCA) were performed through an extra back-up guiding catheter (XB4SH) and a workhorse guidewire, with immediate flow return, followed by stenting with 3 drug-eluting stents resulting in complete restoration of perfusion (door-to-balloon time 33min, Figures 1E-1F).
Further diagnostic workup including chest X-ray (Figure 1H) and echocardiography confirmed the diagnosis of situs inversus with dextrocardia.
The patient always displayed hemodynamic and respiratory stability and was transferred to the chest pain unit for further medical observation and treatment. A guideline-directed medical therapy was initiated including dual antiplatelet therapy (ASS and Prasugrel), a statin, a cardio-selective betablocker, an angiotensin receptor/neprilysin inhibitor, a SGLT2 inhibitor, and a mineralocorticoid-receptor antagonist.
He was discharged after four days.
Situs inversus is a rare condition, but the incidence of acute coronary syndromes is presumed to be similar to that in the general population. Extended ECG recording with additional leads including right precordial leads is crucial in detecting myocardial infarction in this anatomic feature. Moreover, performing coronary catheterization with standard equipment in an inverted fashion may facilitate orientation and interpretation as well as the interventional procedure in situs inversus.
