Author + information
- Received August 21, 2017
- Revision received September 14, 2017
- Accepted October 6, 2017
- Published online December 11, 2017.
- Andrea Mazzanti, MDa,b,
- Riccardo Maragna, MDa,
- Gaetano Vacanti, MDa,
- Anna Kostopoulou, MDa,
- Maira Marino, RSa,
- Nicola Monteforte, MDa,
- Raffaella Bloise, MDa,
- Katherine Underwood, MDa,
- Valentina Tibollo, PhDc,
- Eleonora Pagan, MScd,
- Carlo Napolitano, MD, PhDa,
- Riccardo Bellazzi, PhDc,
- Vincenzo Bagnardi, PhDd and
- Silvia G. Priori, MD, PhDa,b,e,∗ ()
- aMolecular Cardiology, Department of Cardiology, IRCCS ICS Maugeri, Pavia, Italy
- bDepartment of Molecular Medicine, University of Pavia, Pavia, Italy
- cDepartment of Electrical, Computer and Biomedical Engineering, University of Pavia, Pavia, Italy
- dDepartment of Statistics and Quantitative Methods, University of Milan–Bicocca, Milan, Italy
- eFundación Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
- ↵∗Address for correspondence:
Dr. Silvia G. Priori, Molecular Cardiology–IRCCS ICS Maugeri, Via Maugeri, 10-27100 Pavia, Italy.
Background Short QT syndrome (SQTS) is a rare and life-threatening arrhythmogenic syndrome characterized by abbreviated repolarization. Hydroquinidine (HQ) prolongs the QT interval in SQTS patients, although whether it reduces cardiac events is currently unknown.
Objectives This study investigated whether long-term treatment with HQ reduces the occurrence of life-threatening arrhythmic events (LAE) (cardiac arrest or sudden cardiac death) in SQTS patients.
Methods In this cohort study on consecutive SQTS patients, 2 analyses were performed: 1) a matched-period analysis for the occurrence of LAE in 17 SQTS patients who received long-term HQ; and 2) a comparison of the annual incidence of LAE off- and on-HQ in 16 SQTS patients who survived a cardiac arrest.
Results A total of 17 patients (82% male, age 29 ± 3 years, QTc before treatment 331 ± 3 ms) received HQ therapy (584 ± 53 mg/day). Therapy was stopped in 2 cases (12%) due to gastrointestinal intolerance, and 15 patients continued treatment for 6 ± 1 year. QTc prolongation was observed in all patients (by 60 ± 6 ms; p < 0.001). We compared the occurrence of LAE during 6 ± 1 years before and after HQ, observing that patients on HQ experienced a reduction in both the rate of LAE from 40% to 0% (p = 0.03) and the number of LAE per patient from 0.73 ± 0.3 to 0 (p = 0.026). Furthermore, the annual rate of LAE in the 16 patients with a previous cardiac arrest dropped from 12% before HQ to 0 on therapy (p = 0.028).
Conclusions We demonstrated for the first time that treatment with HQ was associated with a lower incidence of LAE in SQTS patients. These data point to the importance that quinidine, that in several countries has been removed from the market, remains available worldwide for patients with SQTS. In the present study, therapy with HQ has been proven to be safe, with a relatively low rate of side effects.
This work was supported by the Ricerca Corrente Funding scheme of the Italian Ministry of Health. Dr. Bellazzi is a shareholder of Biomeris; and is a stakeholder of Engenome. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose. Pedro Brugada, MD, served as Guest Editor for this paper.
- Received August 21, 2017.
- Revision received September 14, 2017.
- Accepted October 6, 2017.
- 2017 American College of Cardiology Foundation
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