Ivabradine, a novel heart rate slower: is it a sword of double blades in patients with idiopathic dilated cardiomyopathy?

OBJECTIVE: To prospectively assess the safety and efficacy of ivabradine in patients with idiopathic dilated cardiomyopathy. METHODS: We included 35 patients with idiopathic dilated cardiomyopathy with an ejection fraction (EF) <40% and heart rate >70 beats/min despite optimal medical therapy, according to the international guidelines in this prospective, non-randomized, single-arm, open-label safety study. Ivabradine was used as an add-on therapy to the maximally tolerated b-blocker in an increasing titrated dose till a target dose of 15 mg/day or resting heart rate of 60 beats/min for 3 months. During follow-up period the safety, patient tolerance and efficacy of this drug were assessed. All patients underwent 12-lead resting electrocardiography and Holter monitoring at inclusion and after 3 months. Statistical analysis was accomplished using paired t-test and Pearson correlation analysis. RESULTS: We found a significant reduction in the resting heart rate by a mean of 25.9 ± 9.4%, without a significant change of blood pressure. There was no prolongation of PR, QTc or QRS durations. Ventricular ectopic activity showed significant reduction (p<0.001). There was a significant correlation between the resting heart rate, NYHA and left ventricular ejection fraction (p<0.001 for both). One patient developed photopsia and decompensation was observed in another patient. CONCLUSION: Ivabradine is a safe and effective drug in reducing resting heart rate, improving NYHA functional class without undesirable effects on conduction parameters or ectopic activity.

QT interval dispersion pattern in patients with acute ischemic stroke: Does the site of infarction matter?

BACKGROUND: QT interval dispersion (QTD) is an independent predictor of outcome following acute neurological events. OBJECTIVES: To explore QTD patterns and their relation to the affected cerebral region in patients with acute ischemic stroke. METHODS: Thirty patients with first acute ischemic stroke (the first stroke the patients had ever experienced) (study group) and 30 healthy controls (control group) were enrolled. Patients underwent magnetic resonance imaging to confirm and localize cerebral damage. Patients in the study group were further subdivided according to the site of infarction into four subgroups - namely, cortical, subcortical, brain stem and cerebellar infarctions, as well as according to insular involvement. All included subjects underwent 12-lead electrocardiography to measure QTD and corrected QT dispersion (QTcD). RESULTS: In the study group, both QTD and QTcD on the first hospitalization day were significantly higher than in the control group (P<0.05 for both). Similarly, in the study group, both QTD and QTcD values on the first hospitalization day were significantly higher than the respective values on the third day (P<0.001 for both). No significant differences were found among the four territorial subgroups, or between right- and left-sided subgroups, regarding QT interval measurements, whether on the first or third day (P>0.05 for all). However, 'first-day' QTD and QTcD of patients with insular involvement were significantly higher than in those without such involvement (P<0.001 for both). CONCLUSIONS: Both QTD and QTcD increased significantly in patients with acute ischemic stroke during the first hospitalization day. This increase of 'first-day' QTD and QTcD was significantly higher in patients with insular involvement than in those without such involvement.