Electrocardiographic markers of sudden death.
ABSTRACT The 12-lead ECG has limited utility to predict the risk for sudden cardiac death in common cardiac diseases such as coronary artery disease and idiopathic dilated cardiomyopathy. However, it is quite useful in diagnosing less common cardiac conditions that are associated with an increased risk for sudden death.
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ABSTRACT: A dynamic model is proposed to study the relationship between the QT and RR intervals of the surface electrocardiogram. The model accounts for the influence of a history of previous RR intervals on each QT, considering that such an influence may vary along the recording time. For identification of the model parameters, an adaptive methodology that uses the regularized Kalman filter is developed. A set of risk markers are derived from the estimated model parameters and they are tested on ambulatory recordings of postmyocardial infarction patients randomized to treatment with amiodarone or placebo. The results of our study show that amiodarone substantially modifies the QT interval response to heart rate changes. Furthermore, the way amiodarone acts on QT adaptation allows to identify patients in which treatment is being effective and separate them from those in which it is not and, consequently, are at higher risk of suffering from arrhythmic death.12/2006: pages 74-77;
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ABSTRACT: Both obstructive sleep apnea (OSA) and prolonged QRS duration are associated with hypertension, heart failure, and sudden cardiac death. However, possible links between QRS duration and OSA have not been explored. Cross-sectional study of 221 patients who underwent polysomnography at our center. Demographics, cardiovascular risk factors and ECG were collected to explore a relationship between OSA and QRS duration. The apnea-hypopnea index (AHI) was positively correlated with QRS duration (r = 0.141, p = 0.03). Patients were divided into 3 groups: AHI < 5 (61), AHI 5-29 (104), and AHI > 30 (55). The mean QRS duration prolonged significantly as OSA worsened (AHI < 5, 85 ± 9.5; AHI 5-29, 89 ± 11.9; and AHI > 30, 95 ± 19.9 ms, p = 0.001). QRS ≥ 100 ms was present in 12.7% of patients with severe OSA compared with 0% in the rest of the sample (p < 0.0001). After adjustment for age, race, and cardiovascular risk factors, this association remained significant in women but not in men. QRS duration and OSA were significantly associated. Severity of OSA independently predicted prolonged QRS in women but not men. Nevertheless, prolongation of QRS duration in either sex may potentiate arrhythmic risks associated with OSA. CITATION: Gupta S; Cepeda-Valery B; Romero-Corral A; Shamsuzzaman A; Somers VK; Pressman GS. Association between QRS duration and obstructive sleep apnea. J Clin Sleep Med 2012;8(6):649-654.Journal of clinical sleep medicine: JCSM: official publication of the American Academy of Sleep Medicine 01/2012; 8(6):649-54. · 2.93 Impact Factor
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ABSTRACT: Sudden cardiac death (SCD) is an important public-health problem with multiple etiologies, risk factors, and changing temporal trends. Substantial progress has been made over the past few decades in identifying markers that confer increased SCD risk at the population level. However, the quest for predicting the high-risk individual who could be a candidate for an implantable cardioverter-defibrillator, or other therapy, continues. In this article, we review the incidence, temporal trends, and triggers of SCD, and its demographic, clinical, and genetic risk factors. We also discuss the available evidence supporting the use of public-access defibrillators.Nature Reviews Cardiology 02/2010; 7(4):216-25. · 10.40 Impact Factor