Electrocardiogram as a predictor of sudden cardiac death in middle-aged subjects without a known cardiac disease

Risk Prediction for Sudden Cardiac Death in the General Population: A Systematic Review and Meta-Analysis

Objective: Identification of SCD risk is important in the general population from a public health perspective. The objective is to summarize and appraise the available prediction models for the risk of SCD among the general population. Methods: Data were obtained searching six electronic databases and reporting prediction models of SCD risk in the general population. Studies with duplicate cohorts and missing information were excluded from the meta-analysis. Results: Out of 8,407 studies identified, fifteen studies were included in the systematic review, while five studies were included in the meta-analysis. The Cox proportional hazards model was used in thirteen studies (96.67%). Study locations were limited to Europe and the United States. Our pooled meta-analyses included four predictors: diabetes mellitus (ES = 2.69, 95%CI: 1.93, 3.76), QRS duration (ES = 1.16, 95%CI: 1.06, 1.26), spatial QRS-T angle (ES = 1.46, 95%CI: 1.27, 1.69) and factional shortening (ES = 1.37, 95%CI: 1.15, 1.64). Conclusion: Risk prediction model may be useful as an adjunct for risk stratification strategies for SCD in the general population. Further studies among people except for white participants and more accessible factors are necessary to explore.

[Diagnostic and prognostic significance of QRS-T angle]

The angle between theQRSandTvectors reflects the consistency or inconsistency of the processes of de- and repolarization of the ventricles of the heart and is considered one of the indicators of global electrical heterogeneity of myocardium. In recent years, the prognostic value of theQRS-Tangle has been demonstrated in relation to total and cardiovascular mortality, both in the population and in various groups of patients. The mechanisms of this phenomenon are not completely clear. The review analyses studies published over the past five years on the relationship between theQRS-Tangle and mortality, as well as coronary heart disease and heart failure. Possible mechanisms for increasing theQRS-Tangle are discussed. Data are given on the use of theQRS-Tangle in diagnostic and prognostic scales, including in combination with other indicators of global electrical heterogeneity of myocardium.

Prolonged QRS independently predicts long-term all-cause mortality in patients with narrow QRS complex undergoing coronary artery bypass grafting surgery (9-year follow-up results)

Aim

We investigated the association of intermediate QRS prolongation with the long-term all-cause mortality in coronary artery bypass grafting (CABG) surgery patients with a narrow QRS complex in the preoperative electrocardiography (ECG).

Material and methods

A total of 221 consecutive patients with narrow QRS (< 120 ms) sinus rhythm who underwent CABG surgery were included in the study. The patients were followed up for 9.2 years postoperatively in terms of mortality outcomes.

Results

Follow-up data were obtained from 211 (173 men, 38 women) of 221 patients. Death occurred in 57 of them. We examined patients in the two groups according to survival outcomes. In multivariate COX regression analysis EuroSCORE (OR = 1.342, 95% CI: 1.167-1.544, p < 0.001), extent of coronary artery disease (OR = 1.768, 95% CI: 1.034-3.020, p = 0.037), QRS duration (OR = 1.029, 95% CI: 1.002-1.058, p = 0.035) and fasting glucose levels (OR = 0.992, 95% CI: 0.984-0.999, p = 0.029) were independent predictors of all-cause mortality. QRS duration > 89.5 ms determined all-cause mortality with a sensitivity of 73.7% and a specificity of 52% (OR = 2.07) due to ROC analysis. All-cause mortality was significantly higher in patients with preop QRS duration > 90 ms from the first year (c² = 6.724, p = 0.010).

Conclusions

In CABG patients with a narrow QRS complex, preoperative intermediate prolonged QRS is an independent predictor of all-cause mortality in long-term follow-up.

Out-of-hospital cardiac arrest: Causes according to autopsy and electrocardiography - Analysis of 781 patients with neither hospital care nor prescribed medication during the preceding two years

BACKGROUND

There is a knowledge gap regarding aetiology of and potential for predicting out-of-hospital cardiac arrest (OHCA) among individuals who are healthy before the event.

AIM

To describe causes of OHCA and the potential for predicting OHCA in apparently healthy patients.

METHODS

Patients were recruited from the Swedish Register of Cardiopulmonary Resuscitation from November 2007 to January 2011. Inclusion criteria were: OHCA with attempted CPR but neither dispensed prescription medication nor hospital care two years before the event The register includes the majority of patients suffering OHCA in Sweden where cardiopulmonary resuscitation (CPR) was attempted. Medication status was defined by linkage to the Swedish Prescribed Drug Register. Cause of death was assessed based on autopsy and the Swedish Cause of Death Register. Prediction of OHCA was attempted based on available electrocardiograms (ECG) before the OHCA event.

RESULTS

Altogether 781 individuals (16% women) fulfilled the inclusion criteria. Survival to 30 days was 16%. Autopsy rate was 72%. Based on autopsy, 70% had a cardiovascular aetiology and 59% a cardiac aetiology. An ECG recording before the event was found in 23% of cases. The ECG was abnormal in 22% of them.

CONCLUSION

Among OHCA victims who appeared to be healthy prior to the event, the cause was cardiovascular in the great majority according to autopsy findings. A minority had a preceding abnormal ECG that could have been helpful in avoiding the event.