Augmented Vector Right ST-Segment Elevation: Pearls and Pitfalls

ST-segment elevation myocardial infarction (STEMI) is characterized by ST-segment elevation in at least 2 contiguous leads, chest discomfort, and the release of biomarkers requiring emergent revascularization. In 2013, the American College of Cardiology Foundation/American Heart Association revised STEMI guidelines to include augmented vector right (aVR) ST-segment elevation to be treated as a STEMI equivalent. However, aVR ST-segment elevation with multilead ST depression can occur in presentations other than occlusive myocardial infarctions. The purpose of this clinical feature is to provide a brief review of aVR ST-segment elevation, explore approaches to clinical decision making, and provide tools to support nurse practitioners caring for patients with cardiac issues.     

The effect of enzyme replacement therapy on clinical outcomes in female patients with Fabry disease – A systematic literature review by a European panel of experts

BackgroundHeterozygous females with Fabry disease have a wide range of clinical phenotypes depending on the nature of their mutation and their X-chromosome inactivation pattern; it is therefore important to examine outcomes of enzyme replacement therapy (ERT) in the female patient population specifically. This paper presents the findings of a systematic literature review of treatment outcomes with ERT in adult female patients.MethodsA comprehensive systematic literature review was conducted through January 2017 to retrieve published papers with original data on ERT in the treatment of Fabry disease. The review included all original articles that presented ERT outcomes data on patients with Fabry disease, irrespective of the study type.ResultsClinical evidence for the efficacy of ERT in female patients was available from 67 publications including six clinical trial publications, and indicates significant reductions in plasma and urine globotriaosylceramide (GL-3) accumulation (in female patients with elevated pre-treatment levels) and improvements in cardiac parameters and quality of life (QoL). To date, data are insufficient to conclude on the effects of ERT on the nervous system, gastrointestinal manifestations, and pain in female patients with Fabry disease.ConclusionsThis review of available literature data demonstrates that ERT in adult female patients with Fabry disease has a beneficial effect on GL-3 levels and cardiac outcomes. The current evidence also suggests that ERT may improve QoL in this patient population, though further studies are needed to examine these results.     

心电图、超声心动图与冠状动脉造影在冠心病诊断中的比较研究

目的 评价心电图(ECG)、超声心动图(UCG)对冠心病的诊断价值。方法 选择216例冠状动脉造影检查的患者，造影前行ECG检查，测ST—T；行UCG检查，测左室射血分数(LVEF)、左室短轴缩短率(FS)、舒张早期充盈峰(E)、舒张晚期充盈峰(A)、E／A比值。结果 ECG与UCG诊断冠心病敏感性分别为90．3％，98．6％，特异性分别为20．8％，11．1％。结论 ECG、UCG对冠心病的诊断具较高的敏感性，且无创、费用低，可作为冠心病诊断的基本方法。     

Estimation of noise level and signal to noise ratio of laplacian electrocardiogram during ventricular depolarization and repolarization

Body surface Laplacian ECG (LECG) has demonstrated its enhanced capability to localize cardiac electrical sources closest to the recording site. The aim of the present study was to evaluate the noise level and signal to noise ratio (SNR) in the LECG as compared to the potential ECG (PECG). Such evaluation is important to determine the applicability of the LECG to localizing and imaging of cardiac electrical activity in an experimental setting. Experimental studies were conducted in six healthy men. A 150-channel PECG was recorded from the anterolateral chest and the LECG was estimated using the finite difference algorithm. The noise level in the PECG and LECG was evaluated using multiple estimation protocols. The signal level during ventricular depolarization and repolarization was also estimated, and the corresponding SNR was calculated. Different filtering techniques were examined to evaluate their effects on the noise level and SNR of the LECG and PECG. The experimental results indicate that with basic signal processing techniques (baseline adjustment, three-point moving average filter, and Wiener spatial filter), the SNR of the LECG is about 30-40% of that of the PECG. Furthermore, the SNR estimated during ventricular depolarization is about three times that obtained during ventricular repolarization for the PECG and LECG. The present study indicates that the LECG derived from the PECG using a local finite difference estimation procedure has satisfactory SNR during the periods of ventricular depolarization and repolarization, and suggests the feasibility of estimating the LECG from the recorded PECG in human subjects in an experimental setting.     

Effects of neferine on Kv4.3 channels expressed in HEK293 cells and ex vivo electrophysiology of rabbit hearts

Aim:

Neferine is an isoquinoline alkaloid isolated from seed embryos of Nelumbo nucifera (Gaertn), which has a variety of biological activities. In this study we examined the effects of neferine on Kv4.3 channels, a major contributor to the transient outward current (I_to) in rabbit heart, and on ex vivo electrophysiology of rabbit hearts.

Methods:

Whole-cell Kv4.3 currents were recorded in HEK293 cells expressing human cardiac Kv4.3 channels using patch-clamp technique. Arterially perfused wedges of rabbit left ventricles (LV) were prepared, and transmembrane action potentials were simultaneously recorded from epicardial (Epi) and endocardial (Endo) sites with floating microelectrodes together with transmural electrocardiography (ECG).

Results:

Neferine (0.1–100 μmol/L) dose-dependently and reversibly inhibited Kv4.3 currents (the IC₅₀ value was 8.437 μmol/L, and the maximal inhibition at 100 μmol/L was 44.12%). Neferine (10 μmol/L) caused a positive shift of the steady-state activation curve of Kv4.3 currents, and a negative shift of the steady-state inactivation curve. Furthermore, neferine (10 μmol/L) accelerated the inactivation but not the activation of Kv4.3 currents, and markedly slowed the recovery of Kv4.3 currents from inactivation. Neferine-induced blocking of Kv4.3 currents was frequency-dependent. In arterially perfused wedges of rabbit LV, neferine (1, 3, and 10 μmol/L) dose-dependently prolonged the QT intervals and action potential durations (APD) at both Epi and Endo sites, and caused dramatic increase of APD₁₀ at Epi sites.

Conclusion:

Neferine inhibits Kv4.3 channels likely by blocking the open state and inactivating state channels, which contributes to neferine-induced dramatic increase of APD₁₀ at Epi sites of rabbit heart.     

Variability of the Diagnostic ECG Pattern in an ICD Patient Population with Brugada Syndrome

Introduction: The spontaneous presence of a coved-type ECG is considered as an important risk factor in Brugada syndrome. However, diagnosis making and risk stratification may be hampered by the dynamic nature of the ECG abnormalities. The objective of this study was to determine the variability and predictive value of the electrocardiogram in Brugada patients implanted with a cardioverter-defibrillator (ICD).
Methods and Results: We analyzed consecutive 12-lead ECGs from 89 ICD patients (44 ± 14 years, 69 males) with Brugada syndrome. A total of 1,161 ECGs were included for analysis (13 ± 8 ECGs/patient). Twenty-four percent of the ECGs/patient were coved-type I, 25% saddleback-type II or III, and 51% normal. Fifty-seven patients had a diagnostic coved-type ECG spontaneously (group A), 32 patients only after drug challenge (group B). In group A, 38% of the ECGs/patient were diagnostic, 25% saddleback-type, and 37% normal. Fifty-five group A patients (96%) had transient normalization and/or conversion to saddleback-type ECGs. During a mean follow-up of 48 ± 35 months, 16 patients (18%) experienced appropriate shocks. All patients with appropriate shocks had spontaneous diagnostic ECGs. They tended to have more coved-type ECGs (36 vs 22%, respectively, P = 0.05) than patients without appropriate shocks.
Conclusions: Analysis of serial ECG recordings in an ICD patient population shows that the Brugada-ECG pattern is highly variable over time. In patients with spontaneous coved-type ECG, only every third ECG is diagnostic and every third ECG normal. Patients with spontaneous coved-type ST-segment elevation have a high incidence of appropriate shocks. Spontaneous saddleback-type electrocardiograms are not helpful for risk stratification.     

QT interval dispersion in the patients with central serous chorioretinopathy

AIM: To evaluate QT dispersion (QTD) in patients with central serous chorioretinopathy (CSC). METHODS: This clinical, comperative, case-control study included 30 patients with CSC at acute phase (Group 1) and 30 age- and sex-matched healthy subjects (Group 2, the control group). From all subjects, a 12-lead surface electrocardiography was obtained. The heart rate (HR), QT maximum (QTmax), QT minimum (QTmin), QT corrected (QTc), QTD and Tmean were manually measured and analyzed. Student’s t-test and Pearson’s method of correlation were used for statistical analysis. RESULTS: The patient and control groups were matched for age, smoking status (rate and duration) and gender. There were no significant differences with regard to these among the groups (P>0.05). The participants included 19 men (63.3%) and 11 women (36.7%) in Group 1, 20 men (66.7%) and 10 women (33.3%) in Group 2. QTmax, QTD and QTc were significantly higher than those of healthy controls (P<0.001 for QTmax, P=0.01 for QTD and P=0.001 for QTc). QTmin, Tmean and HR did not differ significantly between the study groups (P=0.28 for QTmin, P=0.56 for Tmean and P>0.05 for HR). No significant correlation was found between duration of the disorder and QTD values (r=0.13, P>0.05). CONCLUSION: These findings suggest that CSC may be associated with an increase in QTD and that the patients might be at risk for ventricular arrhythmia.     

急性心肌梗死经皮冠状动脉介入治疗后心电图ST段下降幅度与近期预后的观察

目的探讨急性心肌梗死急诊经皮冠状动脉介入治疗(PCI)后心电图ST段下降幅度与患者近期预后的关系.方法将急诊PCI术成功后1小时的18导联心电图(ECG)与入院当时ECG比较,分别测定梗死相关导联最大ST段高度,按抬高的ST段下降幅度分为A组:ST段下降≥50%,B组:ST段下降＜50%,根据对影响患者近期预后相关因素的观察进行比较.结果两组患者在非致死性心脏事件、室壁运动异常、再通后ST段下降又再抬高和住院死亡病例方面差异无统计学意义(P＞0.05),在左心室射血分数(LVEF)方面差异有统计学意义(P＜0.05).结论急性心肌梗死患者经急诊PCI术后,其心电图ST段下降幅度可以作为预示患者近期预后的一个临床实用指标,并进一步指导临床治疗.