Prevalence of amiodarone-related hepatotoxicity in 720 Chinese patients with or without baseline liver dysfunction.

BACKGROUND: The prevalence of hepatotoxicity after longterm oral amiodarone therapy in Chinese patients with or without elevated liver enzymes at baseline is unknown. HYPOTHESIS: Amiodarone may still be safely prescribed for Chinese patients who have baseline liver dysfunction. METHODS: This is a retrospective cross-sectional study. Significant liver dysfunction (SLD) was defined as alanine aminotransferase (ALT) > 2 times upper limit of normal range. RESULTS: Baseline liver function was checked in 628 of the 720 Chinese patients identified. The mean duration of amiodarone use was 615.9 +/- 703.1 days. Ninety patients (14.3%) had elevated baseline ALT. The prevalence of SLD was 3.7% (confidence interval [CI] 2.1-5.3%) and 4.4% (CI 0.2-8.6%) in patients with normal (n = 538) and elevated (n = 90) baseline ALT, respectively (p = 0.765). Therapy was continued in 42 patients with elevated baseline ALT until final follow-up. Eight of these (19.0%) had elevated ALT upon final follow-up, but the derangement was mild (mean ALT 134.8 +/- 145.9 IU/l, median 76 IU/l). During follow up, 24 patients developed SLD and half of these subsequently withdrew from therapy. The ALT levels at final follow-up had improved over time in both groups, but the mean difference was not significant (255.1 +/- 706.4 vs. 131.0 +/- 207.5 IU/l, p = 0.312). CONCLUSION: The prevalence of SLD in Chinese patients taking oral amiodarone with or without elevated baseline ALT was similar (4.4 vs. 3.7%). It seems that amiodarone may be safely prescribed in patients with elevated baseline ALT.

Early left ventricular lead dislodgement related to hyperpnea respiration.

Left ventricular lead dislodgement remained a problem for cardiac resynchronization therapy and is one of the major causes of repeated procedures. We report a 30-year-old lady with possible left ventricular lead dislodgement related to hyperpnea respiration.

Prolongation of atrial effective refractory period with biatrial nonexcitatory stimulation.

BACKGROUND: A nonexcitatory, nonpropagating atrial extrastimulus delivered in the refractory period of the preceding cycle can prolong the atrial effective refractory period (AERP) and prevent the induction of atrial fibrillation by another AE introduced in the vulnerable period. Whether the effect of this nonexcitatory stimulation (NE) is confined only to its application site is unknown. METHODS AND RESULTS: Sixteen consecutive patients were recruited into the study and 2 patients were excluded because of development of more sustained atrial fibrillation. NE was commenced by introduction of a 2.0 msec, 20-mA impulse at 50 msec after the preceding captured pacing impulse. AERP of right atrial septum, a distant site to NE application, was determined at baseline and after 5 minutes of steady pacing at six different protocols: protocol 1, 2, and 3 were conventional pacing at high right atrium, distal coronary sinus, and biatrial sites, respectively, and protocol 4, 5, and 6 were conventional pacing together with NE applied to the same sites as protocol 1, 2, and 3. Biatrial NE (protocol 6 with median AERP = 212.5 msec) significantly prolonged AERP compared with baseline (median AERP = 202.5 msec and P < 0.05), conventional pacing (protocol 1, 2, and 3 with median AERP = 205.0 msec, 205.0 msec, and 205.0 msec, respectively, and all P < 0.05), and single-site NE (protocol 4 and 5 with median AERP = 207.5 msec and 207.5 msec, respectively, and both P < 0.05). CONCLUSION: Biatrial NE resulted in AERP prolongation even at sites distant to NE application. The study result suggests that by adding NE to multi-sites pacing for atrial fibrillation prevention may have additional benefit.

Brugada syndrome unmasked by febrile illness.

The ionic mechanisms responsible for the electrocardiographic phenotype of the Brugada syndrome are temperature dependent. This report describes a healthy young man with ECG changes typical of Brugada syndrome that were unmasked during a febrile illness.