Atrial electromechanical interval may predict cardioembolic stroke in apparently low risk elderly patients with paroxysmal atrial fibrillation.

BACKGROUND: A considerable number of patients with atrial fibrillation (AF) develop cardioembolic stroke (CE) despite low CHADS2 score. We examined the possibility that use of the atrial electromechanical interval (AEMI) improves prediction of CE in patients with paroxysmal AF (PAF), particularly those with low CHADS2 score. METHODS: We consecutively enrolled 108 patients with nonvalvular PAF and 52 healthy subjects as controls. The PAF patients were divided into 2 groups depending on presence (n = 36) or absence (n = 72) of the history of CE. Left atrial (LA) volume index (LAVI), peak myocardial velocity during late diastole (a'), and AEMI as time from onset of P-wave to onset of lateral a' were measured. RESULTS: Patients with PAF had significantly larger LAVI, longer AEMI, and lower lateral a' than those in controls. Area under the curves for LAVI, lateral a', and AEMI for identifying patients with PAF were 0.70, 0.69, and 0.88, respectively. Multivariate logistic regression analysis indicated that age, use of antiarrhythmic drugs, and AEMI, but not LAVI or a', were independently associated with history of CE in patients with PAF. PAF patients were categorized into low risk by CHADS2 score (i.e. CHADS2 score = 0 or 1, n = 60), those with prolonged AEMI (>82 msec) had significantly higher rates of CE than those with ≤ 82 msec (48% vs. 15%, P < 0.05). CONCLUSION: As compared with echocardiographic parameters of LA size and LA function, AEMI appears to be more useful for identifying PAF patients. AEMI may enable to detect high risk PAF patients, especially those categorized into low risk by CHADS2 score.

[Basic investigation of software named "Heart Risk View" to estimate the probability of cardiac events, for the purpose of evaluating the availability in clinical practice].

We validated Heart Risk View (HRV) software for estimating cardiac event probability in patients with suspected ischemic heart disease. This software is based on the results of the J-ACCESS (Japanese Assessment of Cardiac Events and Survival Study by Quantitative Gated SPECT). The HRV software can calculate stress summed scores (SSS), summed rest scores (SRS), and summed difference scores automatically using the 5 point, 20 or 17 segment model of myocardial SPECT images. It can also calculate the probability of cardiac events occurring in patients within 3 years using SSS and parameters obtained from the results of gated SPECT. Changing the threshold of % uptake for determining SPECT scores elevated the agreement of SSS (kappa = 0.269 to 0.657). Cardiac event probability calculated from Perfusion and Function Assessment for Myocardial SPECT (p-FAST) using end systolic volume (ESV), tended to be higher than that calculated from Quantitative Gated SPECT software (QGS). In contrast, cardiac event probability calculated from QGS and p-FAST using left ventricle ejection fraction (LVEF) closely agreed.