Associazione Nazionale Medici Cardiologi Ospedalieri




Sanna Silvia Sassari(Sassari) – Unità Operativa Complessa di Cardiologia AOU Sassari | Lampus Martina Sassari(Sassari ) – Unità Operativa Complessa di Cardiologia AOU Sassari

88-year-old man with arterial hypertension, cognitive impairment, carrier of dual-chamber PM due to sinus node disease. Diagnosis of congenital long QT syndrome (LQT1) approximately 20 years ago during family screening (syncopal episodes in his son positive for LQT1), no history of syncope or major arrhythmias. In home therapy with mirtazapine and norvasc.

He arrived in our cardiac intensive care unit for ACC on torsade de pointes trated with two cycles of CPR and 1 DC shock at 200 Joules with ROSC. On arrival ECG evidence of electrically induced ventricular rhythm, QTc 850 msec. On echocardiogram akinesia of the mid-basal segments of all the LV walls (takotsubo-like) with EF 25-30%. On coronary angiography non critical multivessel coronary disease. At laboratory tests increase of WBC, PCR and PCT, slight plateau movement of troponin, normal electrolytes. The patient underwent a chest CT scan with evidence of an inflammatory focus for which antibiotic therapy was started.

Congenital long QT syndrome (LQTS) is an inherited condition characterized by prolongation of the QT interval (more than 450 ms in men and 460 ms in women), associated with repolarization abnormalities. There are three main forms transmitted via AD: LQT1, LQT2 and LQT3. The most common variant is LQT1 caused by a loss of function mutation in the KCNQ1 gene which causes a reduction in the outgoing potassium current during phase 3 of the action potential. In these patients, episodes of syncope caused by torsade de pointes, major arrhythmias and sudden cardiac death are frequent. Patients with LQTS should avoid taking drugs that can prolong the QT interval such as some antipsychotics, antidepressants (like mirtazapina that can cause QT prolongation, torsade de pointes, ventricular tachycardia and sudden cardiac death if administered at high doses or in patients with predisposing factors), antibiotics. Furthermore, there are various factors that can influence the QT prolongation: electrolyte alterations, physical stress, cerebrovascular events.

The use of mirtazapine for a long period in association with takotsubo syndrome (probably triggered by underlying pneumonia) in a patient with LQTS, may have resulted in massive lengthening of the QT interval causing torsade de pointes and therefore ACC. During the hospitalization, mirtazapine was suspended and nadolol was introduced with a progressive reduction of the QT segment. No new arrhythmic events were recorded.