Debatable issues in automated ECG reporting.

Although automated ECG analysis has been available for many years, there are some aspects which require to be re-assessed with respect to their value while newer techniques which are worthy of review are beginning to find their way into routine use. At the annual International Society of Computerized Electrocardiology conference held in April 2017, four areas in particular were debated. These were a) automated 12 lead resting ECG analysis; b) real time out of hospital ECG monitoring; c) ECG imaging; and d) single channel ECG rhythm interpretation.

Decision to implant a cardioverter defibrillator after myocardial infarction: the role of ejection fraction v. other risk factor markers.

Background: The Multicenter Automatic Defibrillator Implantation Trial showed that in post-myocardial infarction patients with a left ventricular ejection fraction (EF) 0.30, an implantable cardioverter defibrillator (ICD) resulted in a 31% relative reduction in the risk of death when compared with a conventional therapy group. Whether further refinement in risk estimation could be achieved with additional clinical testing to qualify patients for primary prevention with ICDs remains problematic.

Characteristics of heart beat intervals and prediction of death.

Objective: To assess the value for improving risk stratification of measures, unadjusted and adjusted for heart rate, of heart rate variability (HRV) and heart rate turbulence (HRT) based on 2- to 24-h ambulatory electrocardiographic recordings; and to relate this to the decision to use an implantable cardiac defibrillator (ICD) and the attendant consequences on effectiveness and cost-effectiveness.

Background: Risk stratification for high risk or low risk of lethal ventricular arrhythmic events, and hence for a decision about defibrillator implant, most commonly utilizes the left ventricular ejection fraction (LVEF). Electrocardiographic (ECG) approaches include 24-h ambulatory ECG recordings, with counts of ventricular premature contractions (VPCs), measures of heart rate variability (HRV), and heart rate turbulence (HRT).

Structural relationships between measures based on heart beat intervals: potential for improved risk assessment.

Decreased left ventricular ejection fraction is the most commonly used risk factor for identification of patients at high-risk for lethal ventricular arrhythmic events. Twenty-four-hour electrocardiographic (ECG) approaches to risk stratification include: counts of ventricular premature contractions (VPCs), measures of heart rate variability (HRV), and heart rate turbulence (HRT) which has two components, turbulence onset and turbulence slope (TS). Refinement of these ECG risk stratifiers could enhance their clinical utility.

Lack of usefulness of electron beam computed tomography for detecting coronary allograft vasculopathy.

Fifty-five patients with cardiac allografts were studied by electron beam computed tomography for coronary calcification (EBCT CC) and coronary arteriography, and from the latter, a coronary index was calculated using the size, degree of obstruction, and linear extent of disease of each vessel. There was a significant correlation between EBCT CC score and coronary index, but receiver-operating characteristic (ROC) analysis demonstrated unsatisfactory performance of EBCT CC, and 6 patients had no coronary calcification despite having very abnormal coronary indexes. There are pathologic differences between coronary allograft vasculopathy and atherosclerosis, and correspondingly, EBCT CC has limited usefulness in the cardiac transplant population.

Risk stratification in diabetic patients with a previous myocardial infarction.

We used Kaplan-Meier 2-year survival analysis on CAST registry patients to estimate prognostic power of VPC frequency (> or =10/hr), presence of nonsustained ventricular tachycardia (NSVT), left ventricular ejection fraction, and presence of diabetes. We also used meta-analysis of reports in the literature to estimate prognostic power of signal-averaged electrocardiogram (SAECG) and electrophysiological tests (EPS) as well as VPCs, NSVT, and LVEF. Combined results from CAST analysis and literature meta-analysis yielded sensitivity and specificity for VPCs, NSVT, SAECG, LVEF, Diabetes, and EPS.

Risk stratification applied to CAST registry data: combining 9 predictors. Cardiac Arrhythmia Suppression Trial.

Over 200,000 people in the United States die of sudden cardiac death (SCD) every year. Although many of these deaths occur in asymptomatic individuals, the vast majority of deaths occur in people who are under care for existing coronary heart disease. Implantable cardioverter/defibrillators (ICDs) have been shown in several randomized trials to be effective in prolonging lives of those at high risk for sudden cardiac death, but the criteria used in these trials and the ACC/AHA consensus guidelines would cover only a minority of patients.