参仙升脉口服液辅助治疗缓慢性心律失常疗效观察

摘 要 目的: 观察参仙升脉口服液辅助治疗缓慢性心律失常的疗效和安全性。方法：缓慢性心律失常患者80例按就诊顺序分为两组。对照组患者采用常规治疗,观察组患者在对照组基础上加用参仙升脉口服液20 ml,po bid。两组均治疗4周。比较两组治疗前后24 h动态心电图变化、临床疗效及药品不良反应。结果：观察组临床总有效率为92.5%,明显高于对照组的70.0%（P＜0.05）。观察组患者治疗后24 h动态心电图检查结果明显优于对照组（P＜0.05）。治疗中两组患者均未出现明显不良反应。结论：常规治疗基础上加服参仙升脉口服液可有效提高缓慢性心律失常的临床疗效,安全性好,具有推广应用价值。     

Lead I R‐wave amplitude to distinguish ventricular arrhythmias with lead V3 transition originating from the left versus right ventricular outflow tract

BackgroundThe electrophysiology algorithm for localizing left or right origins of outflow tract ventricular arrhythmias (OT‐VAs) with lead V₃ transition still needs further investigation in clinical practice.HypothesisLead I R‐wave amplitude is effective in distinguishing the left or right origin of OT‐VAs with lead V₃ transition.MethodsWe measured lead I R‐wave amplitude in 82 OT‐VA patients with lead V₃ transition and a positive complex in lead I who underwent successful catheter ablation from the right ventricular outflow tract (RVOT) and left ventricular outflow tract (LVOT). The optimal R‐wave threshold was identified, compared with the V₂S/V₃R index, transitional zone (TZ) index, and V₂ transition ratio, and validated in a prospective cohort study.ResultsLead I R‐wave amplitude for LVOT origins was significantly higher than that for RVOT origins (0.55 ± 0.13 vs. 0.32 ± 0.15 mV; p < .001). The area under the curve (AUC) for lead I R‐wave amplitude as assessed by receiver operating characteristic (ROC) analysis was 0.926, with a cutoff value of ≥0.45 predicting LVOT origin with 92.9% sensitivity and 88.2% specificity, superior to the V₂S/V₃R index, TZ index, and V₂ transition ratio. VAs in the LVOT group mainly originated from the right coronary cusp (RCC) and left and right coronary cusp junction (L‐RCC). In the prospective study, lead I R‐wave amplitude identified the LVOT origin with 92.3% accuracy.ConclusionLead I R‐wave amplitude provides a useful and simple criterion to identify RCC or L‐RCC origin in OT‐VAs with lead V₃ transition.     

Arrhythmogenic properties of disordered breathing during sleep in patients with cardiovascular disorders

The purpose of this study was twofold: to establish an ECG respiration monitoring system, and to evaluate the clinical usefulness of this system. Our purpose was to determine how many patients with cardiovascular disorders may have unrecognized sleep apnea and whether such apneic episodes are an important cause of cardiac arrhythmias. The study group included 81 patients, age range 40-95 years, and 13 healthy males, age range 52-72 years. The 24-h ECG respiration recordings were obtained with the two-channel holter recorder. Airflow at the nose using a nasal thermister or chest wall movement by impedance pneumography was recorded as respiration record on the second channel. Sleep apnea was observed 69% and 77-100% in the control subjects and patients with cardiovascular disorders, respectively. Episodes of sleep apnea were most frequent in the patients with old myocardial infarction. Grading of apneas was defined according to the length of apnea. Short duration apneas were observed only in the control subjects, but longer apneic episodes were observed in patients with cardiovascular disorders. Bradyarrhythmias observed were to be relative to apneic episodes longer than 20 s, while ventricular arrhythmias were observed only in the patients with old myocardial infarction, coincident with apneas lasting longer than 40 s. Atrioventricular conduction disturbances were also observed to be related to the occurrence of sleep apnea. These results suggest that 24-h ECG respiration monitoring is useful not only for the observation of sleep apneic episodes, but also in clarifying the relationship between cardiac arrhythmias and apneic episodes.     

The molecular and ionic specificity of antiarrhythmic drug actions

Virtually all clinical antiarrhythmic agents act by reducing ion channel conductance, with sodium (Na+), potassium (K+), and calcium (Ca++) channels the primary targets. Na+ channel blockers increase the risk of ischemic ventricular fibrillation and are relatively contraindicated in the presence of active coronary heart disease. Ca++ channel blockers suppress AV nodal conduction and are used to terminate reentrant supraventricular arrhythmias and control the ventricular response to atrial fibrillation. K+ channels constitute the most diverse group of cardiac ion channels. They are the primary targets of Class III antiarrhythmic drugs, the category of such agents presently undergoing the most active development. The rapid delayed rectifier, IKr, plays a key role in repolarization of all cardiac tissues and is the most common (and often only) target of action potential-prolonging drugs. Unfortunately, because of the ubiquity of IKr and the reverse use-dependent action potential prolongation that results from blocking it, IKr blockers are likely to cause torsades de pointes ventricular proarrhythmia. K+ channel blockers, such as amiodarone and azimilide, that affect the slow delayed rectifier IKs as well as IKr, appear to produce a more desirable rate-dependent profile of Class III action. Recently, much has been learned about the molecular basis of K+ channels based on their role in the congenital long QT syndrome. The availability of molecular clones that encode many of the channels in the human heart allows for the rapid screening of many potential new drugs, making possible the development of "designer" antiarrhythmic drugs with specific profiles of channel-blocking selectivity.     

Cardiac injury with damped sine and trapezoidal defibrillator waveforms

To assess defibrillator-induced cardiac damage, 49 anaesthetized greyhounds received either no shocks (control group) or five shocks from a defibrillator delivering one of five waveforms (Lown, Edmark, Belfast damped sine waveforms: 5 and 20 ms trapezoidal waveforms). At 3 days the hearts of the 36 surviving dogs were examined for macroscopic damage. The Belfast and Edmark waveforms caused significantly more damage (mean 21.1 +/- SEM 2.9 g and 16.0 +/- 3.7 g) respectively than the Lown waveform (3.5 +/- 1.3 g) P less than 0.01. The 20 ms trapezoid caused significantly more damage (8.1 +/- 3.1 g) than the 5 ms pulse (0.7 +/- 1.3 g) P less than 0.05). The ventricular ectopic counts per minute were not significantly different in the three sine wave and 20 ms trapezoidal groups at 24 and 48 h (P greater than 0.05), but at 2 and 72 h were significantly greater in the Belfast and Edmark groups than in the Lown group (2 h, Belfast P less than 0.01, Edmark P less than 0.05: 72 h P less than 0.05). At 15 min there was more right chest ST-segment elevation in the Belfast than in the Lown, Edmark and 20 ms trapezoid groups (P less than 0.01), while left chest ST elevation was greater in the Belfast and Edmark than in the Lown (P less than 0.05) and 20 ms trapezoid groups (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

Hepatotoxic slimming aids and other herbal hepatotoxins

Perceptions of safety and/or cultural mores prompt individuals to seek herbal slimming aids in preference to conventional dietary, physical activity and medication-based protocols. In recent years, terpenoid-containing dietary supplements have been implicated in causing severe and sometimes fatal hepatotoxicity. Teucrium polium (germander) was the first of these herbal products to be clearly linked to cases of acute liver failure. Subsequently, similar hepatotoxicity has been observed with other members of the Teucrium genus. While diterpenoid-derived reactive metabolites are central to germander hepatotoxicity, it may also be that the hepatic effects of compounds such as Sho-saiko-to, Centella asiatica and Black cohosh are linked to their triterpenoid content. Other non-terpenoid-containing herbal remedies marketed for weight reduction have been causally associated with significant liver injury. Important among these are preparations containing N-nitrosofenfluramine, usnic acid and ephedra alkaloids. Finally, we review recent data on known and emerging hepatotoxins such as Boh-Gol-Zhee, Kava, pyrrolizidine alkaloids and Shou-Wu-Pian. Better public and physician awareness through health education, early recognition and management of herbal toxicity and tighter regulation of complementary/alternative medicine systems are required to minimize the dangers of herbal product use.     

Is extensive atrial fibrosis in the setting of heart failure associated with a reduced atrial fibrillation burden?

Atrial fibrillation (AF) affects 10–50% of patients with chronic heart failure (HF) and is associated with poor long‐term prognosis. AF is commonly associated with atrial structural remodeling (ASR), principally characterized by atrial dilatation and fibrosis. However, the occurrence of AF in the full spectrum of ASR encountered in patients with HF is poorly defined. Experimental studies have presented evidence that extensive ASR can be accompanied with a reduced burden of AF, secondary to a prominent depression of atrial excitability. This reduction in AF burden is associated with severe atrial fibrosis rather than with dilatation. Clinical studies of patients with HF point to the possibility that advanced ASR is associated with a less frequent AF occurrence than moderate ASR. Our goal in this review is to introduce the hypothesis that AF is less likely to occur in severe versus moderate atrial ASR in the setting of HF and that it is severe atrial fibrosis‐associated depression of atrial excitability that reduces AF burden.