Influence of age and gender on clinical outcomes following percutaneous coronary intervention for acute coronary syndromes

Background Gender and age are non-modifiable factors influencing clinical outcomes in acute coronary syndromes (ACS). There is evidence that coronary artery disease pathophysiology varies in women. We therefore evaluated the effect of age and gender on clinical outcomes in patients with ACS undergoing percutaneous coronary interventions (PCI). Methods Among 3178 (25% female) consecutive ACS patients who underwent PCI at Liverpool Hospital, Sydney from 2003 to 2010, using femoral access in 98% of cases, we determined late events including mortality, myocardial infarction and bleeding according to Bleeding Academic Research Consortium (BARC) criteria. Results Females compared with males were older (median 68 vs. 60 years; p<0.001), and were more likely to have diabetes (30% vs. 22% p<0.001), hypertension (62% vs. 49%, p<0.001), anaemia (26% vs. 15%, p<0.001), and renal impairment (43% vs. 20%, p<0.001); they were more likely to be non-smokers (19% vs. 30%, p<0.001). Females had less class B2/C lesions (64% vs.68%, p=0.048), but had more calcified lesions (20% vs. 11%, p<0.001), and smaller stent diameters (2.75[2.5-3.0] vs. 3.0[2.75-3.5] mm, p<0.001). Females had higher three-year mortality rates (11% vs. 7.0%, p=0.001), and more type 2-5 BARC bleeding post-PCI (22% vs. 16%, p=0.003). Among patients under 55 years (n=988), mortality and bleeding were higher in females (6.0% vs. 3.0%, p=0.028) and (26% vs. 14%, p=0.001) respectively. There was no effect of gender on mortality or bleeding in patients 55 years and over. However, on multivariable stepwise regression analysis, female gender was not an independent predictor of mortality, but was a significant predictor of bleeding (OR=1.84 [95% CI:1.38–2.45], p<0.001). Conclusion Bleeding and mortality were higher in younger females with ACS who underwent PCI. While females had more post-PCI bleeding events, which were associated with late mortality, gender per se was not an independent predictor for mortality. © 201

A modern Wilson's Central Terminal electrocardiography database

Wilson's Central Terminal (WCT) is an artificially constructed virtual reference potential for surface electrocardiography (ECG). It is derived by averaging the voltage of the right arm (ΦR), left arm (ΦL), and left leg (ΦF), and is assumed to be steady and with negligible amplitude during the cardiac cycle. In order to measure WCT, in 1954, Bayley and Kinard encased volunteers inside a metal structure that was immersed in water for the duration of the recording. Due to the impracticality in measuring WCT using this method, it is an accepted methodological error in modern ECG. This study employed a novel ‘15-lead ECG device’ in which the ‘right leg’ is used as the ground reference terminal for measuring all signals. It was able to record WCT components (ΦR, ΦL, and ΦF) and a 12-lead ECG. Data from 85 patients (35 (41%) patients were female) at Campbelltown Hospital were recorded. Patients with pacemakers were excluded from the dataset. The average age of the study population was 65.31 years (SD 11.59). The absolute average amplitudes of WCT components among all patients were (ΦR = 0.076 mV, ΦL = 0.070 mV, and ΦF = 0.044 mV). Ten-second periods of recording without any artefacts was selected, and 413 10-second periods were extracted. It was found that recorded WCT is highly individual, and has standard ECG characteristics, including a P-wave, QRS complex, and T-wave

Einthoven unipolar leads : towards a better understanding of Wilson Central Terminal

Einthoven unipolar leads include the potential of the right arm, left arm, and left leg which, by definition, are used to form the Wilson central terminal (WCT) as the average of these three limbs leads. In a traditional 12-lead ECG system, it is not possible to measure WCT directly. It is assumed to both be steady during the cardiac cycle with the assumed value most commonly being -2/3 of the augmented vector foot (aVF) lead. Using our novel ECG device that records Einthoven unipolar leads in addition to traditional 12-lead ECG signals, we investigate whether the WCT and aVF are proportional and the WCT can accurately be replaced by -2/3 of the aVF lead. We use the Einthoven unipolar leads features to evaluate both of the assumptions in regards to the WCT amplitude and value

Minimization of the Wilson’s Central Terminal voltage potential via a genetic algorithm

Abstract Objective The Wilson Central Terminal (WCT) is an artificially constructed reference for surface electrocardiography, which is assumed to be near zero and steady during the cardiac cycle; namely it is the simple average of the three recorded limbs (right arm, left arm and left leg) composing the Einthoven triangle and considered to be electrically equidistant from the electrical center of the heart. This assumption has been challenged and disproved in 1954 with an experiment designed just to measure and minimize WCT. Minimization was attempted varying in real time the weight resistors connected to the limbs. Unfortunately, the experiment required a very cumbersome setup and showed that WCT amplitude could not be universally minimized, in other words, the weight resistors change for each person. Taking advantage of modern computation techniques as well as of a special ECG device that aside of the standard 12-lead Electrocardiogram (ECG) can measure WCT components, we propose a software minimization (genetic algorithm) method using data recorded from 72 volunteers. Result We show that while the WCT presents average amplitude relative to lead II of 58.85% (standard deviation of 30.84%), our minimization method yields an amplitude as small as 7.45% of lead II (standard deviation of 9.04%)

On the Einthoven Triangle: A Critical Analysis of the Single Rotating Dipole Hypothesis

Since its inception, electrocardiography has been based on the simplifying hypothesis that cardinal limb leads form an equilateral triangle of which, at the center/centroid, the electrical equivalent of the cardiac activity rotates during the cardiac cycle. Therefore, it is thought that the three limbs (right arm, left arm, and left leg) which enclose the heart into a circuit, where each branch directly implies current circulation through the heart, can be averaged together to form a stationary reference (central terminal) for precordials/chest-leads. Our hypothesis is that cardinal limbs do not form a triangle for the majority of the duration of the cardiac cycle. As a corollary, the central point may not lie in the plane identified by the limb leads. Using a simple and efficient algorithm, we demonstrate that the portion of the cardiac cycle where the three limb leads form a triangle is, on average less, than 50%

WCTECGdb: A 12-Lead Electrocardiography Dataset Recorded Simultaneously with Raw Exploring Electrodes’ Potential Directly Referred to the Right Leg

With this paper we communicated the existence of a surface electrocardiography (ECG) recordings dataset, named WCTECGdb, that aside from the standard 12-lead signals includes the raw electrode biopotential for each of the nine exploring electrodes refereed directly to the right leg. This dataset, comprises of 540 ten second segments recorded from 92 patients at Campbelltown Hospital, NSW Australia, and is now available for download from the Physionet platform. The data included in the dataset confirm that the Wilson’s Central Terminal (WCT) has a relatively large amplitude (up to 247% of lead II) with standard ECG characteristics such as a p-wave and a t-wave, and is highly variable during the cardiac cycle. As further examples of application for our data, we assess: (1) the presence of a conductive pathway between the legs and the heart concluding that in some cases is electrically significant and (2) the initial assumption about the limbs potential stating the dominance of the left arm concluding that this is not always the case and that might requires case to case assessment

Computing a new central terminal for ECG recording using combined genetic algorithm and linear regression from real patient data

Modern electrocardiography (ECG)1 uses the Wilson Central Terminal (WCT) as a reference point for the majority of leads. WCT is assumed to be near zero and steady during the cardiac cycle. However, due to the measurement encumbrances of the real amplitude of WCT, this assumption has never been verified in clinical practice. Using our own recently developed 15-lead ECG device that can measure WCT components in addition to 12-lead ECGs in a clinical setting, we propose a framework to derive a New Central Terminal (NCT) with demonstrated less variation and near zero amplitude during the cardiac cycle. Our method is based upon application of a Genetic Algorithm (first 1000 samples), and then a linear regression to calculate the NCT for the rest of the recording

Unipolar cardiac leads between history and science

The surface electrocardiography (ECG) uses a virtual reference point to measure the potential of chest electrodes. This reference potential is known as Wilson central terminal (WCT) and is assumed negligible (near zero) in amplitude. Consequently, the precordial leads have been named as the unipolar leads. Although this assumption was found incorrect immediate after this reference potential was introduced, it was difficult to measure its real amplitude. We recently introduced a 15-lead electrocardiography device that can record the traditional ECG leads in combination with the raw potential of limbs and chest electrodes directly referred to the circuit grounding. Consequently, we are able to record the potential of the raw chest electrodes, which we named as true unipolar chest leads. The aim of this study is to have a clear understanding of the WCT potential and its influence on the chest leads. Our records show that the true unipolar leads may be more sensitive for detecting cardiac diseases in the left anterior descending coronary artery in patients with non-ST elevation reported on chest leads

Evaluation of serial high sensitivity troponin T levels in individuals without overt coronary heart disease following exercise stress testing

Background Detectable levels of high sensitivity (cardiac) troponin T (HsTnT), occur in the majority of patients with stable coronary heart disease (CHD), and often in 'healthy' individuals. Extreme physical activity may lead to marked elevations in creatine kinase MB and TnT levels. However, whether HsTnT elevations occur commonly after exercise stress testing (EST), and if so, whether this has clinical significance, needs clarification. Methods To determine whether HsTnT levels become elevated after EST (Bruce protocol) to >= 95% of predicted maximum heart rate in presumed healthy subjects without overt CHD, we assayed HsTnT levels for similar to 5 h post-EST in 105 subjects (median age 37 years). Results Pre-EST HsTnT levels 14 ng/L, with troponin elevation occurring at least three hours post-EST. Additionally, a detectable >= 50% increase in HsTnT levels (4.9 -> 9ng/L) occurred in 28 (27%) of subjects who during EST achieved >= 95% of their predicted target heart rate. The median age of the subjects with HsTnT elevations to >14ng/L post-EST was higher than those without such elevation (42 and 36 years respectively; p=0.038). At a median follow-up of 13 months no adverse events were recorded. Conclusion The current study demonstrates that detectable elevations occur in HsTnT post-EST in 'healthy' subjects without overt CHD. Future studies should evaluate the clinical significance of detectable elevations in post-EST HsTnT with long-term follow-up for adverse cardiac events

Cardiac invasive electrophysiology studies with radiofrequency ablation without onsite cardiothoracic surgical back-up in a new cardiac electrophysiology laboratory : single-centre experience

ntroduction: Previous studies of invasive cardiac electrophysiology (EP) and radiofrequency catheter ablation (RFA) concluded that procedures can be safely performed successfully in selected groups of patients, by experienced staff, without on-site cardiothoracic surgery back-up. We aim to report a single centre experience. Methods and results: All consecutive patients (n = 57) who underwent cardiac EP studies and/or RFA at a cardiac EP laboratory, between 12 October 2016 and 13 December 2017 at Campbelltown Hospital in New South Wales, were evaluated. The cardiac EP laboratory was opened in October 2016 with one EP session per week. Patients who require complex RFA procedures such as pulmonary vein isolation for atrial fibrillation and ventricular tachycardia ablation were transferred to a nearby tertiary hospital. Median age was 57 years (interquartile range 39–54 years) and 63% were male. The indications and numbers of invasive EP studies and RFA are shown in the Figure 1. There were no access site complications, no major adverse cardiovascular events (death, stroke, major bleeding, perforation, tamponade, or complete heart block). No patients required emergency surgery. Conclusion: Cardiac EP studies with RFA are safely performed in certain indications for procedures without surgical back-up. Favourable clinical outcomes were obtained without complications during the first year experience. These results are consistent with the current published data