Peak endocardial acceleration reflects heart contractility also in atrial fibrillation.

Previous studies demonstrated that peak endocardial acceleration (PEA) in sinus rhythm is related to LV dP/dtmax. Until now, PEA was never evaluated during R-R interval variations in AF. The aim of this study was to establish the behavior of PEA in AF and the relationship of PEA versus LV dP/dtmax. Six sheep (65 +/- 6 kg) were instrumented with a LV Millar catheter and with an accelerometer lead. AF was induced and PEA, LV dP/dtmax, and ECG were monitored. AF persisted for 5 +/- 1.3 minutes. From sinus rhythm to AF, the heart rate went from 92 +/- 3 to 130 +/- 35 beats/min (P < 0.05), LV dP/dtmax from 684 +/- 18 to 956 +/- 344 mmHg/s (P = NS) and PEA from 0.82 +/- 0.06 to 0.94 +/- 0.33 g (P = NS). The correlation between PEA and LV dP/dtmax was significative in sinus rhythm (r = 0.7, P < 0.05) and in AF (r = 0.8, P < 0.05). A positive relationship was found between the preceding interval and PEA (r = 0.4 +/- 0.07, P < 0.05) and LV dP/dtmax (r = 0.61 +/- 0.08, P < 0.05), while a negative one was found between the prepreceding interval and both PEA (r = -0.39 +/- 0.11, P < 0.05) and LV dP/dtmax (r = -0.64 +/- 0.05, P < 0.05). At the onset of AF, LV dP/dtmax and PEA showed similar changes: beat-to-beat correlation between PEA and LV dP/dtmax was high. As for LV dP/dtmax, PEA is positively related to the preceding interval and negatively related to the prepreceding interval. These data confirm that PEA reflects heart contractility also during AF and hold promise for the use of this sensor in therapeutic implantable devices.