Bidirectional Tachycardia Induced by Herbal Aconite Poisoning

Tai, Yu‐Tzu; Lau, Chu‐Pak; But, Paul Pui‐Hay; Fong, Ping-Ching; Li, John Po-Shan

doi:10.1111/j.1540-8159.1992.tb06849.x

Cited by 54 publications

(18 citation statements)

References 20 publications

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“…BVT is a rare form of tachycardia known to be associated with digitalis toxicity, aconitine poisoning, 16 or familial periodic paralysis. 17 Leenhardt et al 1 described that the morphology of BVT typically showed a right bundle-branch block pattern with alternating right and left QRS-axis deviation.…”

Section: Mechanism Of Bvtmentioning

confidence: 99%

Cellular Mechanisms Underlying the Development of Catecholaminergic Ventricular Tachycardia

2005

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Background-Mutations in the ryanodine 2 receptor (RyR2) gene have been identified in patients with catecholaminergic polymorphic ventricular tachycardia. We examined the cellular basis for the ECG features and arrhythmia mechanisms using low-dose caffeine to mimic the defective calcium homeostasis encountered under these conditions. Methods and Results-A transmural ECG and action potentials were recorded simultaneously from epicardial, M, and endocardial cells in arterially perfused canine ventricular wedge preparations. Caffeine alone produced no change (10 to 100 mol/L) or a slight abbreviation (300 mol/L) of the QT interval and no change in transmural dispersion of repolarization. Isoproterenol (100 nmol/L) alone induced sustained monomorphic ventricular tachycardia (VT) that originated in the epicardium in 3 of 14 wedge preparations. Isoproterenol in the presence of caffeine (100 to 300 mol/L) induced epicardial VT in 9 of 16 wedge preparations. Delayed afterdepolarization-induced triggered beats that originated in the epicardium were associated with an increased T peak -T end interval and transmural dispersion of repolarization. Bidirectional VT developed in 11 of 16 wedge preparations as a consequence of alternation in the origin of ectopic activity between endocardial, M, and epicardial regions. Single extrastimuli delivered during sustained epicardial VT induced a rapid polymorphic VT/ventricular fibrillation (VF) in 3 of 9 wedges. Spontaneous polymorphic VT was observed in 3 of 16 preparations. Propranolol (1.0 mol/L) or verapamil (1.0 mol/L) completely suppressed ectopic activity that arose from the epicardium and prevented induction of polymorphic VT. Conclusions-Our data suggest delayed afterdepolarization-induced extrasystolic activity serves to trigger catecholamineinduced VT/VF under conditions of defective calcium handling. Epicardial origin of the ectopic beats increases transmural dispersion of repolarization, thus providing the substrate for the development of reentrant tachyarrhythmias that underlie rapid polymorphic VT/VF.

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Section: Mechanism Of Bvtmentioning

confidence: 99%

Cellular Mechanisms Underlying the Development of Catecholaminergic Ventricular Tachycardia

2005

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“…Recent studies have also shown the electrophysiological effects of some herbal medicine, which led to expansion of our approach in the use of herbal medicines in the field of cardiac electrophysiology. Some examples include: (Ι) suppressing and preventing effect of Wenxin Keli, a herbal extract, on atrial and ventricular arrhythmias by depression of Ito and INa-dependent electrophysiological parameters (37,38), (ΙΙ) anti-arrhythmic effect of saffron extract (39) and its effects on the Wenckebach block cycle length and nodal functional refractory period in in vitro model (40), (ΙΙΙ) anti-arrhythmic and electrophysiological effects of European Lamiaceae Leonurus cardiaca extract as calcium channels I (Ca.L) blockade, reduction of repolarizing current I (K.r) and prolongation of action potential duration (41) and (IV) bidirectional tachycardia induced by aconites present in a Chinese herbal decoction (42).…”

Section: Discussionmentioning

confidence: 99%

Evaluation of Melissa officinalis (Lemon Balm) effects on heart electrical system

Joukar

Asadipour

2015

Res Cardiovasc Med

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Background:Melissa officinalis, an herbal drug, is well known and frequently applied in traditional and modern medicine. Yet, there is inadequate information regarding its effects on electrical properties of the heart. The present study attempted to elucidate the effects of Melissa officinalis aqueous extract on electrocardiogram (ECG) in rat. Objectives: ECG is an easy, fast and valuable tool to evaluate the safety of used materials and drugs on heart electrical and conductivity properties. Many drugs with no cardiovascular indication or any overt cardiovascular effects of therapeutic dosing become cardiotoxic when overdosed (16). On the other hand, there are numerous substances and drugs that can cause ECG changes, even in patients without a history of cardiac disease. Therefore, this study was conducted to elucidate safety and outcome of one-week administration of M. officinalis aqueous extract on blood pressure and ECG parameters of rats. Materials and Methods: Four animal groups received tap water (control group), aqueous extracts of Melissa officinalis 50 (M50), 100 (M100) and 200 (M200) mg/kg/day, respectively and orally for a week. ECG and blood pressure were recorded on the eighth day of experiment. Results: Consumption of Melissa officinalis extract associated with prolonged QRS interval (P < 0.05 for M50 and M100 groups and P < 0.01 for M200 group versus the control group, respectively), prolonged QTc and JT intervals (P < 0.01 for different M groups versus the control group) and prolonged TpTe interval (P < 0.001 when M groups compared with the control group) of ECG. However, different doses of the extract had no significant effect on RR interval, PR interval, amplitudes of ECG waves, heart rate and blood pressure. Conclusions: For the first time, this study revealed that consumption of Melissa officinalis extract is associated with significant ECG alterations in rat. Future studies are necessary to determine potential clinical outcomes.

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“…Aconitine, a component of the Fuzi, binds with Na + channels, causing persistent myocardial activation that leads to an intracellular Na + gradient and activates the Na + -Ca 2+ exchanger (NCX). Activation of NCX contributes to Ca 2+ overload and delayed afterpolarisation (DAD) 2. During DAD periods, depolarising myocardium act as ectopic ventricular pacemakers that trigger the His-Purkinje system in either the right or left bundle branch, leading to right or left bundle branch block 3…”

Section: Answer: Amentioning

confidence: 99%