Introduction: The onset of ventricular arrhythmias (VAs) during an exercise test (ET) is a common finding in asymptomatic middle-aged individuals. However, their clinical significance is uncertain, especially in absence of myocardial ischaemia or structural heart disease (SHD). VAs from the right ventricular outflow tract (RVOT) are the most common in a structurally normal heart and they can be exacerbated by several triggers.
Case report: An asymptomatic 53-year-old woman without cardiovascular risk factors and good functional status was referred for a cardiologic evaluation before uterine polypectomy. Laboratory exams showed moderate iron deficiency anaemia (IDA), due to uterine chronic blood loss, treated with iron sulfate and folic acid. The ECG pointed out a QS aspect in leads V1-V3. A preserved regional and global systolic function and a mild concentric hypertrophy of the left ventricle (LV) were observed at the transthoracic echocardiogram. The ET with echocardiography, according to the Bruce protocol, was interrupted due to physical exhaustion, reaching the theoretical maximum heart rate, in absence of ischaemic repolarization alterations and a normal segmental wall kinetic with a preserved contractile reserve of the LV. However, after the first minute of recovery, multiple monomorphic non-sustained ventricular tachycardias (NSVT) originating from the RVOT were observed. In the following minutes their frequency reduced with the onset of isolated premature ventricular contractions (PVCs), terminating with a single polymorphic NSVT of 3 beats. During both exercise and recovery, were observed occasional runs of atrial tachycardia. A significant coronary artery disease was ruled out by coronary angiography (CA). Subsequently, a contrast-enhanced Cardiac Magnetic Resonance revealed a mid-wall late gadolinium enhancement in the basal segment of the inferior wall. The patient underwent uterine polypectomy without complications, restoring haemoglobin (Hb) values during the following months. Subsequently, Holter ECG and ET did not revealed VAs. Thus, the patient resumed moderate aerobic physical activity without any adverse arrhythmic events.
Discussion: The RVOT VAs are commonly idiopathic and triggered by several factors. CA and CMR may provide additional information during the diagnostic algorithm. IDA may promote VAs after exercise in predisposed patients without SHD, requiring a prompt restoration of Hb and iron levels.
