The combined assessment of TWA and LP was associated with a high positive predictive value for an arrhythmic event after acute MI. Therefore, it could be a useful index to identify patients at high risk of arrhythmic events.

Late potentials are a noninvasive risk stratifier in patients with Brugada syndrome. These results may support the idea that conduction disturbance per se is arrhythmogenic.

SUMMARYMicrovolt T-wave alternans (TWA) and QT interval dispersion (QTD), which reflect temporal and spatial repolarization abnormalities, respectively, have been proposed as useful indices to identify patients at risk for ventricular tachyarrhythmias (VTs). The purpose of this study was to clarify which repolarization abnormality marker is more useful in predicting arrhythmic events in patients with dilated cardiomyopathy (DCM).Forty-two consecutive nonischemic DCM patients underwent the assessment of TWA and QTD. Patients undergoing antiarrhythmic pharmacotherapy, except β-blockers and those with irregular basic rhythms, were excluded from entry. Eight patients were also excluded because of indeterminate test results. Therefore, 34 DCM patients were prospectively assessed. The end point of the study was the documentation of VT defined as ≥ 5 consecutive ectopic beats during the follow-up period.TWA and QTD (≥65 msec) were positive in 24 (80%) and 11 (37%) of 30 patients with available follow-up data, respectively. There was no relationship between TWA and QTD. During a follow-up of 13±11 months, VTs occurred in 13 patients (43%). In Cox regression analysis, TWA was a significant risk stratifier (p=0.02), whereas QTD was not. The sensitivity, specificity, and positive and negative predictive values of TWA in predicting VTs were 100%, 35%, 54%, and 100%, respectively.TWA could be a useful noninvasive index to identify patients at risk for VTs in the setting of DCM. This study may suggest that temporal repolarization abnormality is associated more with arrhythmogenesis than with spatial repolarization abnormality in DCM patients. (Jpn Heart J 2001; 42: 451-457)

Left ventricular dyssynchrony was smaller in patients with high septal pacing. The results show that 2D-STE is useful for detection of differences in left ventricular mechanical dyssynchrony in patients with permanent pacemaker implantation, in addition to TDI.

A curious retrograde conduction in connection with the coronary sinus (CS) musculature was observed in 2 patients. After the failed ablation procedure, the atrial electrogram during ventricular pacing presented double potentials, the first component of which was sharp and with an activation sequence that was the same before ablation (CS distal to proximal). The second component of the double potentials was dull and had a decremental property; its activation sequence was in reverse (proximal to distal). In both cases, the first component disappeared after successful ablation. These findings suggest that the first component was the CS electrogram conducted over the accessory pathway and the second component was the left atrial electrogram conducted through the inter-atrial septum. The separation of each electrogram is probably the result of a block between the accessory pathway connected to the CS musculature and the left atrium. These are unusual cases of an accessory pathway connected to the CS musculature, which separates the left atrial myocardium at the distal portion from the ostium.