Familiar, inappropriate sinus node tachycardia
█ Original article
Borbola József, Somogyi Anikó
Gottsegen György Országos Kardiológiai Intézet, Felnőtt Kardiológiai Osztály, Elektrofiziológiai és Pacemaker Terápiás Osztály, Budapest
Aims: The worldwide information with familiar, inadequate, inappropriate sinus node tachycardia is limited. Our aim was to publish of our own experiences with the medical examinations and drug therapy of these patients.
Patients and methods: In the last ten years from 104 patients we noticed 4 patients (3.8%) with the accumulation of inappropriate sinus-node tachycardia [father (57 years old), daughter (29 years old); and a brother (22 years old) and sister (20 years old)]. All patients underwent 12 leads ECG, chest X-ray, echo, laboratory investigation, Holter-monitoring and transtelephonic ECG observations.
Results: Patients had no structural heart disease. Laboratory values (Hgb: 146±11 g/l; TSH: 2.12±0.40 µmol/l) were within normal values. The resting heart rate of the patient group was 117±10/min on the ECG. The results of Holter recording (expressed as minimal-maximal and (average) heart-rate/min) without drug therapy showed high heart rate values: 59±8/min – 160±14 – (94±6/min). During the patients symptoms the transtelephonic ECG showed episodes of sinus tachycardias in each patients. The bisoprolol (2×5 mg/day) therapy (Holter: 54±5/min – 132±16/min (p<0.05) – (79±9/min (p<0.05) and the ivabradine treatment (2×5 mg/day) (Holter: 50±1/min – 148±8/min (p<0.05) – 79±3/min) as well improved not only the Holter-parameters, but also the patient’s symptoms (EHRA score control: 2.4±0.5, during treatment 1.0±0 (p<0.005).
Conclusion: The familiar inappropriate sinus node tachycardia is a rare clinical syndrome with a propensity for higher rates of sinus tachycardias. Both of the beta-blocking drug bisoprolol and the If channel blocker ivabradine proved to be useful for treatment. In the background of this nomotope cardiac arrhythmia the gene mutation of the HCN4 channel protein (R524Q) was suggested.