Feasibility of Blood Pressure Measurement With a Wearable (Watch-Type) Monitor During Impending Syncopal Episodes

Abstract

Background We assessed the reliability and feasibility of blood pressure (BP) measurements by means of a new wearable watch-type BP monitor (HeartGuide) in detecting episodes of hypotensive (pre)syncope induced by tilt table test. Methods and Results An intrapatient comparison between systolic BP (SBP) measured by means of the HeartGuide device and noninvasive finger beat-to-beat BP monitoring was undertaken both at baseline in supine position and repeatedly during tilt table test in patients evaluated for reflex syncope. Intrapatient fall of systolic BP from baseline was measured. Eighty-one patients (mean age, 61±19 years; 46 women) were included. Overall, HeartGuide was able to yield BP values at the time of BP nadir in 58 (72%) patients (average HeartGuide SBP 102±18 mm Hg, versus finger SBP 101±19 mm Hg). Compared with baseline, the maximum SBP decrease was on average -28.5±27.8 and -30.3±33.9 mm Hg respectively (Lin's concordance correlation coefficient=0.78, r=0.79, P=0.001). In the subgroup of 38 patients with tilt table test induced (pre)syncope, the average HeartGuide SBP during symptoms was 97±16 mm Hg, and the finger SBP was 94±18 mm Hg. Compared with baseline, the maximum SBP decrease was on average -35.2±29.3 and -43.3±31.8 mm Hg, respectively (Lin's concordance correlation coefficient=0.83, r=0.87, P=0.001). Conclusions Our data indicate that the HeartGuide BP monitor can detect low BP during presyncope and that its measure of SBP change is consistent with that simultaneously obtained through continuous BP monitoring, despite some intrapatient variability. Thus, this device might be useful in determining the hypotensive nature of spontaneous (pre)syncopal symptoms, a possibility that should be verified by field studies.

Keywords: blood pressure monitoring; finger blood pressure; syncope; wearable (watch‐type) monitor.

Figure 1. Watch‐type wearable blood pressure monitor HeartGuide.

Figure 2. Method of measurement of blood pressure by HeartGuide (see text).

Figure 3. Screening log and patient flow.

BP indicates blood pressure; and TTT, tilt table test.

Figure 4. Trend in systolic blood pressure (SBP) in patients who had HeartGuide measurements available at the time of the primary end point.

A, Trend in SBP in 58 patients who had HeartGuide measurements available at the time of the primary end point. The mean finger SBP value at the nadir is derived from 57 patients (one patient missing). The mean SBP value at 1‐minute upright tilt table test is related to 57 patients in the HeartGuide group and to 57 patients in the control group (1 patient missing in each group, because of artifacts). B, Trend in HeartGuide SBP and finger SBP in 38 patients who had (pre)syncope (positive response) during tilt table test. BP indicates blood pressure; and SBP, systolic blood pressure.

Figure 5. Scatter diagrams with regression line (continuous blue), 95% CI (dotted blue) and line of equity (thin red line).

A, Data from 57 patients who had measurable HeartGuide values during tilt table test. Finger blood pressure was not available in 1 patient. B, Data from 38 patients who had (pre)syncope (positive response) during tilt table test. BP indicates blood pressure; SBP, systolic blood pressure; and TTT, tilt table test.