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. Author manuscript; available in PMC: 2018 Oct 1.
Published in final edited form as: Trends Cardiovasc Med. 2017 May 10;27(7):463–472. doi: 10.1016/j.tcm.2017.05.003

Figure 4.

Figure 4

SKNA recordings from a health volunteer undergoing the Valsalva maneuver. Signals from lead V1 were bandpass filtered between 500–1000 Hz to detect SKNA and bandpass filtered between 0.5–150 Hz to detect the ECG. Integraded SKNA (iSKNA) was calculated over a 100-ms window. A: Increased SKNA was associated with heart rate (HR) acceleration. B: Higher magnification of SKNA showing baseline spontaneous nerve activity (a) and large variations of nerve discharges associated with tachycardia (b). C: increased SKNA and HR were evident during Valsalva maneuver. Dotted red lines mark the start and stop of the maneuver. D: Magnified boxed segment from Panel C showing phases II–IV of the Valsalva maneuver, demonstrating that SKNA was not synchronous with the QRS complex. (From Doytchinova et al, Heart Rhythm 2017)(47)