Cristoforo D’Ascia, Antonio Cittadini, Giuseppe Riccio, Luigi De Vito, Salvatore Longobardi, Salvatore Luca D’Ascia, Carlo Pappone*,
Luigi Sacca.
Department of Internal Medicine, “Federico II” University Medical School Naples, *San Raffaele Hospital, Milan, Italy
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It has been reported that conditions of chronic GH excess such as
acromegaly are associated with increase of atrial and ventricular arrhythmias. To date, no study has addressed
whether GH administration modifies electrophysiological cardiac parameters and/or the induction of arrhythmias
in an acute setting.
To this aim, we performed two endocavitary electrophysiological studies (EPS) in 12 patients, before and after
2 hours of intravenous GH administration or placebo, in randomized double blind. Ten patients were referred for
evaluation of episodes palpitations and two for paroxysmal atrial fibrillation. An echocardiographic study
excluded structural or functional abnormalities in all patients. Patients received no drug from at least 1 month.
Patients were divided in two groups: group A, GH administration (4UI i.v.), 6 patients and group B, placebo
administration, 6 patients.
Electrophysiological cardiac parameters assessed included: electrophysiological intervals (A-H, H-V, Q-T, R-R),
sinus nodal function (Corrected Sinus Node Recovery Time CSNRT), atrial ventricular nodal function (Alternate
Wenckebach Period, WP and Atrio-Ventricular Node Effective Refractory Period, AVN-ERP), right sinus atrial
function (Right Atrial Effective Refractory Period, RA-ERP), right ventricular function (Right Ventricular Effective
Refractory Period, RV-ERP), and arrhythmia inducible evaluation by standard stimulation protocols.
All electrophysiological parameters displayed no changes after GH administration. Furthermore, no ventricular
arrhythmia was inducible at both the baseline and the post-GH EP study. In 2 patients atrial fibrillation (1 placebo
and 1 GH administration) was induced at the baseline study, and also during the post-treatment evaluation,
without differences in its duration and characteristics. No correlation was found between electrophysiological
parameters and hormonal levels
In conclusion, GH acute administration does not appear to modify the susceptibility to supraventricular or
ventricular arrhythmias in a selected population.
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