Torsades de pointes after adenosine administration.

Adenosine can produce arrhythmias, which are generally short living. It may induce PACs and PVCs, sinus bradycardia, and atrial fibrillation. There have been reports of transient polymorphic VT (torsades de pointes) in patients with LQTS and others in people with normal QT interval. We report a case of a long episode of polymorphic VT induced by adenosine. A 27 year old woman received 6 mg adenosine for PSVT, which terminated and torsades de pointes developed, persisting for 17 seconds and terminated spontaneously. This is the longest described duration of the torsades after adenosine administration in patients with normal QT interval.

Head-up tilt table testing in syncope: safety and efficiency of isosorbide versus isoproterenol in pediatric population.

BACKGROUND: The aim of this study was to compare the diagnostic value and safety of sublingual isosorbid dinitrate (ISDN) with intravenous isoproterenol (ISOP) during head-up tilt table testing (HUTT) in pediatric patients with suspected neurocardiogenic syncope. METHODS: One hundred thirty-six consecutive pediatric patients complaining of presyncope or syncope were submitted to HUTT for the first time. Those who did not develop syncope or presyncope during passive HUTT for 20 minutes underwent repeated HUTT with either 1.25 to 2.5 mg sublingual ISDN or intravenous ISOP (1-3 mug/min) for 20 minutes. There were 54 boys and 82 girls, aged 10 to 18 years with an average of 15.5 +/- 2.4 years and a median of 16 years. Among the patients with cardioinhibition or mixed responses, the severity of the bradyarrhythmia was scored 1 to 3 (restoration of effective rhythm within 10 seconds, 10-20 seconds, and >20 seconds while back to supine position, respectively). RESULTS: During the passive period, 24 (17.6%) of 136 patients had a positive response to HUTT. Syncope was observed in another 44 patients during either ISDN or ISOP period (14/58 [24.1%] and 30/54 [55.5%] with ISDN vs ISOP, respectively, P < .05). The time to symptoms was shorter with both ISDN and ISOP compared with passive period (6.5 +/- 2.9, 6.3 +/- 5.9, and 10.3 +/- 4.4, minutes, respectively, P < .05). The severity score for cardioinhibition response was significantly higher with ISDN compared with the passive period and ISOP (2 +/- 0.8, 1.25 +/- 0.45, and 1.26 +/- 0.45, respectively, P < .01). CONCLUSIONS: Sublingual ISDN is less sensitive and less safe compared to intravenous ISOP in assessing pediatric age patients with suspected neurocardiogenic syncope and with a negative result in tilt test without provocation. The simplicity of ISDN use should be weighed against the risk of longer symptoms with ISDN.

Thoracic aortic atherosclerosis in patients with aortic regurgitation.

OBJECTIVE: Hemodynamic forces are potential determinants of aortic atherosclerosis. Aortic regurgitation (AR) alters the flow pattern in the aorta. However, the association between AR and aortic atherosclerosis is not well known. METHODS: We assessed the presence, extent and distribution of atherosclerotic lesions in the aorta of 42 patients with chronic AR and compared them to 40 patients with similar risk factor profile for atherosclerosis and no valvular disease. RESULTS: There was no difference in the extent of atheroma in the ascending aorta and aortic arch between patients with and without AR. Descending aortic atheroma was evident in 25 patients with AR (60%) and 12 patients without AR (30%, p=0.01). AR was found to be the only predicting factor for the presence of aortic atherosclerosis in the descending aorta (odds ratio 4.1; 95% CI 1.2-14.3, p=0.03). CONCLUSIONS: There is an increased prevalence of descending aortic atherosclerosis in patients with significant AR.