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Aims: Syncope without prodromes in subjects with normal heart and normal electrocardiogram (ECG) is classified as non-classical neurally mediated syncope and is characterized by low adenosine plasma levels (APLs) and frequent asystolic syncope. We assessed the efficacy of theophylline, a non-selective adenosine receptor antagonist, in preventing syncopal events., Methods and Results: Participants received an implantable cardiac monitor, underwent APL measurement, and received oral theophylline at maximum tolerated dose (starting dose 300 mg b.i.d.). They were compared with a historical cohort of untreated patients with implantable cardiac monitor who had the same inclusion criteria and were balanced with the propensity score (PS) method as regard age, sex, lifetime syncopal episodes, APL, and antihypertensive drugs. Primary endpoint was time to first syncopal recurrence at 24 months. There were 76 patients in the theophylline group and 58 in the control group. Syncope recurred in 25 (33%) patients in the theophylline group and in 27 (47%) patients in the control group, with an estimated 2-year recurrence rate of 33% and 60%, respectively, and a hazard ratio of 0.53 [95% confidence interval (CI), 0.30-0.95; P = 0.034]. Most of the benefit of theophylline is derived from reduction of syncope due to asystolic atrioventricular (AV) block (hazard ratio of 0.13; 95% CI, 0.03-0.58; P = 0.008). Thirty (39%) patients discontinued theophylline after a median of 6.4 (interquartile range 1.7-13.8) months due to side effects., Conclusion: Theophylline was effective in preventing recurrences in patients with syncope without prodromes, normal heart, and normal ECG. The benefit was greater in patients with syncope due to asystolic AV block., Clinicaltrials.gov Identifier: NCT03803215., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2021. For permissions, please email: journals.permissions@oup.com.)

Aims: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited arrhythmic disorder with a highly malignant clinical course. Exercise-stress test is the first-line approach to diagnose suspected individuals. We sought to elucidate the value of exercise-stress test for predicting mutations and future cardiac events in CPVT-family relatives., Methods and Results: The present study included 67 asymptomatic relatives (24 ± 15 years) of 17 genetically positive CPVT probands, who underwent exercise-stress test without any medication and genetic testing. Exercise-stress test, which was considered positive with the induction of ventricular tachycardia or premature ventricular contractions consisting of bigeminy or couplets, was positive in 17 relatives (25%). Genetic analysis disclosed mutations in 16 of these 17 relatives (94%) and in 16 of the 50 relatives (32%) with negative exercise-stress test; the sensitivity and specificity for a positive genotype were 50 and 97%, respectively (P< 0.001). Among 32 mutation carriers, cardiac events occurred in 7 of the 16 relatives with positive and 2 of the 16 relatives with negative exercise-stress test during the follow-up period of 9.6 ± 3.8 years, and four with positive and two with negative stress test were not on regular beta-blocker treatment at these events. In the 16 relatives with positive stress test, those on beta-blocker treatment demonstrated a trend of lower cardiac event rate (Log-rank P= 0.054)., Conclusion: In asymptomatic relatives of CPVT probands, exercise-stress test can be used as a simple diagnostic tool. Nevertheless, because of the low sensitivity for predicting mutations and future cardiac events in those with negative stress test, genetic analysis should be performed to improve patient management.

We report the first documentation of spontaneous ventricular fibrillation by a loop recorder in a patient with an ECG pattern of early repolarization (ER) in the inferior leads and presenting with syncope.

Although amiodarone appears to have few pro-arrhythmic effects, torsade de pointes (TdP) has been observed during long-term drug administration, usually in conjunction with electrolyte disturbances, a change in drug dosage, or concomitant drug therapy. We report two cases of amiodarone-induced TdP shortly after administration of a low dose of oral amiodarone, in the absence of predisposing factors.

Objectives: To evaluate the usage and diagnostic yield of the implantable loop-recorder (ILR) in detection of the mechanism of syncope and in guiding therapy in patients aged >/=65 years and comparing them with those <65 years., Design: This was a two-hospital, observational, prospective study in consecutive patients with unexplained syncope who underwent an ILR implantation. Between November 1997 and December 2002, a total of 2052 patients with syncope were evaluated (local population of 590,000 inhabitants). The diagnosis remained unexplained in 371 (18%). Of these, 103 patients (5% of the total, 28% of those with unexplained syncope) received an ILR., Results: There were 70 (76%) patients aged >/=65 years and 25 (24%) <65 years. ILR implantation was 110 and 9 per million inhabitants per year, respectively. During a mean follow-up of 14+/-10 months, syncope was recorded in 52 patients. Compared with younger patients those older had a 2.7 higher syncope recurrence rate (56% vs 32%, P=0.03); arrhythmias were 3.1 times more likely to be responsible for syncope (44% vs 20%, P=0.03). More patients >/=65 years finally received ILR-guided therapy (42% vs 20%, P=0.04). Among the 29 patients (25 of those >/=65 years) who received specific antiarrhythmic therapy, only one (3%), had recurrence of syncope during the subsequent follow-up of 40+/-18 months., Conclusions: In patients referred for investigation of unexplained syncope, the older subjects are more likely to have an indication for ILR implantation than those younger, ILR has a higher diagnostic value, an arrhythmia is more likely to be detected and successfully treated.