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Early repolarization associated with sudden cardiac death is based on the presence of >1-mm J-point elevations in inferior and/or lateral leads with horizontal and/or downsloping ST segments. Automated electrocardiographic readings of early repolarization (AER) obtained in clinical practice, in contrast, are defined by ST-segment elevation in addition to J-point elevation. Nonetheless, such automated readings may cause alarm. We therefore assessed the prevalence and prognostic significance of AER in 211,920 patients aged 18 to 75 years. The study was performed at a tertiary medical center serving a racially diverse urban population with a large proportion of Hispanics (43%). The first recorded electrocardiogram of each individual from 2000 to 2012 was included. Patients with ventricular paced rhythm or acute coronary syndrome at the time of acquisition were excluded from the analysis. All automated electrocardiographic interpretations were reviewed for accuracy by a board-certified cardiologist. The primary end point was death during a median follow-up of 8.0 ± 2.6 years. AER was present in 3,450 subjects (1.6%). The prevalence varied significantly with race (African-Americans 2.2%, Hispanics 1.5%, and non-Hispanic whites 0.9%, p <0.01) and gender (male 2.4% vs female 0.6%, p <0.001). In a Cox proportional hazards model controlling for age, smoking status, heart rate, QTc, systolic blood pressure, low-density lipoprotein cholesterol, body mass index, and coronary artery disease, there was no significant difference in mortality regardless of race or gender (relative risk 0.98, 95% confidence interval 0.89 to 1.07). This was true even if J waves were present. In conclusion, AER was not associated with an increased risk of death, regardless of race or gender, and should not trigger additional diagnostic testing., (Copyright © 2014 Elsevier Inc. All rights reserved.)

This case illustrates the difficulties sometimes encountered by clinicians when using algorithms in diagnosing a wide-complex tachycardia based on a 12-lead EKG.

Introduction: Normalization of the pre-excited QRS following ablation is accompanied by repolarization changes but their directional relationship to changes in ventricular activation has not been well characterized., Methods: Accordingly, we measured QRS and T wave vectors and QRS-T angles from 12 lead ECG recordings immediately before and after accessory pathway (AP) radiofrequency ablation in 100 consecutive patients. Patients with bundle branch block, intraventricular conduction defect or intermittent pre-excitation were excluded, leaving a study group of 45 patients: 35 with pre-excitation and 10 with concealed APs., Results: With AP ablation, changes occurred in the QRS and T wave vectors and QRS-T angles that were essentially equal and opposite, so that the newly normalized QRS complex and QRS vector were accompanied by a T wave whose vector approximated that of the pre-ablation QRS vector. This tended to maintain a large QRS-T angle: 72 degrees +/- 50 degrees before, and 54 degrees +/- 34 degrees after QRS normalization (p = NS). A QRS-T angle >40 degrees was found before and after ablation in 22/35 patients (63%) with baseline pre-excitation; but never in patients with a concealed AP (p = 0.001). The angle between the pre-excited QRS and the post-ablation T wave was 35 degrees +/- 37 degrees, and

Pacemaker patients frequently have concomitant atrial tachyarrhythmias, most importantly atrial fibrillation, because numerous underlying electrical or structural diseases can potentiate both conditions. DDD pacing (or atrial) appears superior to VVI in limiting the occurrence of atrial fibrillation and its associated negative sequela. Sick sinus syndrome, a prior history of atrial fibrillation, and advanced age predispose patients with DDD devices to postimplant atrial fibrillation, yet the majority of these high-risk patients are manageable in DDD throughout their follow-up. DDD patients at significant risk for developing atrial arrhythmias require special attention regarding the selection and programming of their devices. Rate modulation, higher lower rate limits, special approaches toward upper rate limit management, and antitachycardia capabilities may all be important aspects in their management. The combined use of AV node ablation and ventricular or DDD pacing to manage patients with refractory atrial tachyarrhythmias is becoming an increasingly accepted therapeutic approach.