Electrophysiological Phenotyping Of Patients at Risk of Ventricular Arrhythmia and Sudden Cardiac Death

Background Brugada syndrome is a genetic disorder of cardiac conduction that predisposes patients to spontaneous ventricular arrhythmia and sudden cardiac death. Although Brugada syndrome is one of the most common causes of sudden cardiac death, patients presenting with the syndrome often go misdiagnosed. This error has potentially fatal consequences for patients, who are at risk for sudden cardiac death without appropriate management. Objective To increase the critical care professional’s knowledge of Brugada syndrome through detailed description of the characteristic electrocardiographic findings, an algorithmic approach to electrocardiogram evaluation, and a case report of a patient with a previously missed diagnosis of Brugada syndrome. The essential concepts of epidemiology, pathophysiology, clinical presentation, risk stratification, and management are reviewed for critical care professionals who may encounter patients with the syndrome. Diagnosis Patients typically present with syncope or cardiac arrest and an abnormal electrocardiographic finding of ST-segment elevation in the precordial leads. The diagnosis of Brugada syndrome centers on identification of its electrocardiographic characteristics by critical care professionals who routinely evaluate electrocardiograms. Critical care professionals, especially nurses and advanced practice nurses, should be proficient in recognizing the electrocardiographic appearance of Brugada syndrome and initiating appropriate management. Interventions Management strategies include prevention of sudden cardiac death through lifestyle modification and placement of an implantable cardioverter-defibrillator. Critical care professionals should be aware of commonly used medications that may exacerbate ventricular arrhythmia and place patients at risk for sudden cardiac death. Conclusion Increased awareness of Brugada syndrome among critical care professionals can decrease patient morbidity and mortality.

Download Full-text

Abstract 15714: Prediction of Sudden Cardiac Death With Automated High-Throughput Analysis of T-Wave Heterogeneity in Standard 12-Lead Electrocardiogram

Circulation ◽

10.1161/circ.130.suppl_2.15714 ◽

2014 ◽

Vol 130 (suppl_2) ◽

Author(s):

Tuomas Kenttä ◽

Bruce D Nearing ◽

Kimmo Porthan ◽

Jani T Tikkanen ◽

Matti Viitasalo ◽

...

Keyword(s):

At Risk ◽

Relative Risk ◽

Sudden Cardiac Death ◽

General Population ◽

Cardiac Death ◽

Left Ventricular ◽

Adjusted Relative Risk ◽

T Wave ◽

Increased Risk ◽

Patients At Risk

Introduction: Noninvasive identification of patients at risk for sudden cardiac death (SCD) remains a major clinical challenge. Abnormal ventricular repolarization is associated with increased risk of lethal ventricular arrhythmias and SCD. Hypothesis: We investigated the hypothesis that spatial repolarization heterogeneity can identify patients at risk for SCD in general population. Methods: Spatial R-, J- and T-wave heterogeneities (RWH, JWH and TWH, respectively) were automatically analyzed with second central moment technique from standard digital 12-lead ECGs in 5618 adults (46% men; age 50.9±12.5 yrs.) who took part in Health 2000 Study, an epidemiological survey representative of the entire Finnish adult population. During average follow-up of 7.7±1.4 years, a total of 72 SCDs occurred. Thresholds of RWH, JWH and TWH were based on optimal cutoff points from ROC curves. Results: Increased RWH, JWH and TWH (Fig.1) in left precordial leads (V4-V6) were univariately associated with SCD (P<0.001, each). When adjusted with clinical risk markers (age, gender, BMI, systolic blood pressure, cholesterol, heart rate, left ventricular hypertrophy, QRS duration, arterial hypertension, diabetes, coronary heart disease and previous myocardial infarction) JWH and TWH remained as independent predictors of SCD. Increased TWH (≥102μV) was associated with a 1.9-fold adjusted relative risk (95% confidence interval [CI]: 1.2 - 3.1; P=0.011) and increased JWH (≥123μV) with a 2.0-fold adjusted relative risk for SCD (95% CI: 1.2 - 3.3; P=0.004). When both TWH and JWH were above threshold, the adjusted relative risk for SCD was 3.2-fold (95% CI: 1.7 - 6.2; P<0.001). When all heterogeneity measures (RWH, JWH and TWH) were above threshold, the risk for SCD was 3.7-fold (95% CI: 1.6 - 8.6; P=0.003). Conclusions: Automated measurement of spatial J- and T-wave heterogeneity enables analysis of high patient volumes and is able to stratify SCD risk in general population.

Download Full-text