Upgrade your Tilt Testing for Syncope Assessment

Medical Need:

Syncope is very frequent in general population.^[1] At the age of 15 prevalence in females is 47% and 31% in males^[2,3]. 6% of all hospital admissions are due to unexplained syncope and falls. Huge amounts of money are spent on these patients to diagnose the underlying cause of these syncopes. (Computer tomography of the heart, NMR, implantable loop recorder, 24 hour ECG, 24 hour BP, 24 hour EEG, carotid sonography, angiography, etc.)

Thus, a profound, simple and cheap assessment of syncope is required. State-of-the-art syncope assessment is performed with the help of a "Tilt Table" and requires continuous monitoring of hemodynamics^[1,4]. An analysis of the patient's hemodynamic and autonomic function is performed since the short-term evaluation of cardiovascular disturbances indicates the underlying (dys-)function.

Standard auscultatory or oscillometric sphygmomanometers take about one minute of measurement time - short term disturbances in hemodynamics can not be tracked.

Solution:

The devices developed by CNSystems enable continuous CNAP^® blood pressure measurement without any interruptions, even in syncopal situations caused by profound hypotension.

The Task Force^® Monitor is the "state-of-the-art" solution which provides all relevant hemodynamic parameters completely synchronized - and meets the requirements of the International Guidelines (ESC, ACC)^1,4. Online tracking of transient events during tilt table testing delivers insight into the complex regulatory mechanism during the measurement. Read here how special indicators help to investigate syncope.

We also offer customized syncope software and report generation:

diagnostic tools, i.e. callipers to measure drop in heart rate and blood pressure
advanced print reports including ECG paper
data export: ASCII Text, MS-Excel^®, Matlab^®

The CNAP^® Monitor 500 HD targets hospitals and doctors with a limited budget as an attractive alternative to the Task Force^® Monitor. It offers continuous noninvasive CNAP^® blood pressure, stroke volume and cardiac output from pulse wave analysis.

Medical Benefit:

The continuous noninvasive monitoring of blood pressure is the essential parameter to diagnose patients with syncope. In combination with the noninvasive monitoring of cardiac output, physicians gain high quality physiological information at no risk for the patient.

A customized syncope software with the Task Force^® Monitor ensures the ease of use for clinicians when studying patients with syncope, featuring diagnostic tools and advanced print reports for each case.

Video Testimonial Syncope Assessment

Economic Benefit:

CNSystems' Task Force^® Monitor provides profound, simple and cheap assessment of syncope. Therefore, it helps to reduce the huge number of hospital admissions due to unexplained falls.

Scientific Studies:

Many studies report the usefulness of the Task Force^® Monitor for the assessment of hemodynamic and autonomic parameters during tilt testing:

Laranjo et al. (2012) from the university of Lisbon, Portugal characterized hemodynamic and autonomic response during a tilt table program in patients with neurocardiogenic syncope. They concluded that tilt testing may be an effective therapeutic option with long-term benefits.

Researchers from the University Taipei, Taiwan, used the Task Force^® Monitor to study the modifications of autonomic activity and baroreceptor response during a tilt-induced vasovagal syncope (Cheng et al., 2010). During head-up tilt test patients with vasovagal syncope (VVS) had increased LF/HF ratio and decreased baroreceptor sensitivity. VVS subjects had vascular sympathetic dysfunction and postural cardiac sympathetic hyperactivity.

Additional Information:

This paragraph provides advanced diagnosis methods for syncope assessment and autonomic function. Trend recordings with the Task Force^® Monitor for a healthy subject and a subject with autonomic dysfunction are discussed.

Hemodynamic trend recording of a healthy patient on a tilt table during supine rest, head-up tilt to 60 degrees and tilting back to supine position is shown in Figure 1.

After passive tilting, blood drains to lower body parts and, as a result, venous return to the heart is reduced. This decrease causes a drop in stroke volume (SV) to approximately 70%. As a reaction to sympathetic tone, heart rate (HR) increases. Due to the rise of the heart rate, cardiac output (CO) decreases less than stroke volume, but it is still clearly lower than in supine rest. At the same time, sympathetic tone leads to vasoconstriction and a rising total peripheral resistance (TPR). The increase of heart rate and total peripheral resistance has the effect that CNAP^® blood pressure remains almost unchanged. Only an increase of diastolic blood pressure is noticed due to the
increase of total peripheral resistance and the resulting decreased diastolic decay.

One can see that all parameters fluctuate, whereas different frequencies of the rhythmic oscillations can hardly be observed or even interpreted. Applying the "mathematical prism" of the Task Force^®Monitor software these fluctuations can be interpreted.

In Figure 2 the power spectra of the heart rate variability (HRV) of the healthy patient on the tilt table is shown.

Until the head-up tilt (mark 2 at ~ 12min) a peak at breathing frequency (~ 0.25 Hz) can be noticed. This corresponds with high parasympathetic or vagal activity during rest. After head-up tilt, this 0.25 Hz peak immediately disappears and a new rhythmic activity around 0.1 Hz comes up, which corresponds with sympathetic drive. Again, after tilting back (mark 3 at ~ 23min) the sympathetic peak at 0.1 Hz disappears and the vagal activity peak at 0.25 Hz slowly returns.

In comparison to healthy people, subjects with classical autonomic failure show unchanged heart rate and only little variability during head up tilt (Figure 3). Total peripheral resistance decreases because of the impaired autonomic (sympathetic) control of the peripheral vessels. As a consequence, blood pressure decreases and additional short blood pressure drops can be detected (arrows in the blood pressure band). Note that the stroke volume and cardiac output remain constant. In healthy subjects stroke volume should decrease due the reduced venous return during head-up tilt. The patient from Figure 3 still compensates the orthostatic dysfunction with an increase of cardiac inotropy as stroke volume almost does not change. This impaired behavior of increased inotropic state even during standing may lead to cardiac failure.

A further marker for autonomic failure is the parasympathetic dysfunction. Figure 4 shows that parasympathetic activity is missing in supine position.

Figure 4: Heart rate variability of autonomic failure

In addition, the baroreceptor reflex sensitivity is an early indicator of autonomic failure. In healthy subjects baroreceptor sensitivity modulates from more than 10 ms/mmHg in supine position to 6 - 10 ms/mmHg in upright position. This is caused by the sympathetic activation during head-up tilt, where the sensitivity of the cardiovascular systems can be reduced. In patients with autonomic failure baroreceptor sensitivity does not change and is always low (< 5 ms/mmHg).

Devices designed for Syncope Assessment:

Case Report:

Syncope Assessment with Task Force Monitor
Size: 604.29 KB Format: PDF

References:

[1] Brignole M., Moya A, et al. Guidelines for the diagnosis and management of syncope (version 2018). Eur Heart J. 2018; 00: 1-69. doi:10.1093/eurheartj/ehy037

[2] Ganzeboom KS, Colman N, Reitsma JB, Shen WK, Wieling W. Prevalence and triggers of syncope in medical students. Am J Cardiol 2003;91:1006–1008.

[3] Serletis A, Rose S, Sheldon AG, Sheldon RS. Vasovagal syncope in medical students and their first-degree relatives. Eur Heart J 2006;27:1965–1970.

[4] Strickberger SA, Benson DW, et al. AHA/ACCF scientific statement on the evaluation of syncope: from the American Heart Association Councils on Clinical Cardiology, Cardiovascular Nursing, Cardiovascular Disease in the Young, and Stroke, and the Quality of Care and Outcomes Research Interdisciplinary Working Group. J Am Coll Cardiol. 2006; 47(2):473-84.