. Author manuscript; available in PMC: 2010 Feb 17.

Published in final edited form as: IEEE Trans Ultrason Ferroelectr Freq Control. 2009 Mar;56(3):565–574. doi: 10.1109/TUFFC.2009.1073

TABLE I.

Timing Characteristics Measured from the Envelope of the AE and ECG Signals.

Heart	SL	EL	t_e-AE [ms]	t_e-ECG [ms]	t_p-AE [ms]	w_{−3 dB}- AE [ms]	t_p-ECG [ms]	w_{−3 dB}- ECG [ms]	SNR-AE [dB]
A	AT	1–2	168.8 ± 0.7	162.4 ± 0.9	171.3	6.8	167.8	16.6	15.7
		2–3	165.4 ± 0.6	151.6 ± 2.0	169.1	9.9	160.4	19.6	13.5
		3–4	145.4 ± 0.8	144.2 ± 12.0	149.1	9.2	150.2	11.0	11.1
	AP	1–2	12.9 ± 1.1	14.4 ± 1.5	16.6	6.8	21.2	12.8	14.7
		2–3	22.4 ± 1.0	30.2 ± 1.8	49.8	6.2	49.8	13.2	10.2
B	AT	1–2	157.7 ± 0.8	135.0 ± 12.0	160.8	5.5	143.6	14.6	11.9
		2–3	135.5 ± 0.4	133.0 ± 0.8	137.6	6.2	137.6	12.0	10.2
	AP	1–2	28.3 ± 0.5	18.8 ± 1.7	31.4	8.0	25.4	14.0	13.4
		2–3	29.5 ± 0.8	28.3 ± 1.2	33.8	6.2	34.1	12.0	13.4

The parameters are illustrated in Fig. 4. The acronyms are as follows: SL = stimulation location, AT = right atrium, AP = apex, EL = electrode pair, t_p = time-to-peak, t_e = onset latency, w_{−3 dB} = the −3 dB width of the signal. AE = acousto-electric, ECG = low frequency electrocardiograms, SNR = signal-to-noise ratio.