A feasibility study into the exploration of possible mechanisms underlying inappropriate sinus tachycardia (IST) syndrome in pregnancy.
This is a non-interventional, physiological study which will explore the feasibility of examining autonomic function and related haemodynamic variables in pregnant women with and without inappropriate sinus tachycardia, with the aim of providing scope for future research. Sinus tachycardia (normal heart rhythm but fast heart rate) is common and usually related to an obvious cause (e.g. exercise such a running or cycling) and doesn't cause any untoward symptoms. In rare cases however, sinus tachycardia can occur without an obvious cause (i.e. it is inappropriate to the situation) and can cause distressing symptoms such as palpitations, dizziness and breathlessness at rest or with minimal exertion. This syndrome of inappropriate sinus tachycardia is poorly understood and can be difficult to manage; especially when the affected individual is pregnant. In order to understand the condition better and improve care pathways we aim to measure various features of the cardiovascular system in pregnant women with and without IST.
Study Type
OBSERVATIONAL
Enrollment
200
12-lead electrocardiogram
24-hour heart rate monitor used to calculate mean heart rate and heart rate variability
Heart Rate Variability (HRV) and Baroreflex sensitivity (BRS): Resting and exercise HRV and BRS calculated from ECG, Dundee Step test and blood pressure measurements.
Addenbrookes Hospital
Cambridge, United Kingdom
RECRUITINGFeasibility of examining autonomic function and related haemodynamic variables in pregnant women with and without inappropriate sinus tachycardia
Number of women in each group who agree to participate in the study
Time frame: Up to 3 years
Assessment of autonomic function and related haemodynamic variables in pregnant women with and without inappropriate sinus tachycardia
Heart rate variability (HRV) at rest using time and frequency domain (e.g. SDNN ms and LF and HF), combined to give absolute power in ms².
Time frame: Up to 3 years
Assessment of autonomic function and related haemodynamic variables in pregnant women with and without inappropriate sinus tachycardia
Baroreflex sensitivity (BRS) at rest calculated from the change in systolic pressure and change in R-R interval to give change in pressure per change in RR interval, measured in milliseconds (mmHg/ms)
Time frame: Up to 3 years
Assessment of ANS function in pregnant women with and without IST, at rest and during mild exercise
Stroke volume in ml
Time frame: Up to 3 years
Assessment of ANS function in pregnant women with and without IST, at rest and during mild exercise
Heart Rate Variability during mild exercise (3 minute step test) using time and frequency domain (e.g. SDNN ms and LF and HF), combined to give absolute power in ms².
Time frame: Up to 3 years
Assessment of ANS function in pregnant women with and without IST, at rest and during mild exercise
Cardiac Output in litres/minute
Time frame: Up to 3 years
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Cardiac output (CO), stroke volume (SV) and systematic vascular resistance (SVR) will be assessed and calculated using a non-invasive, inert gas re-breathing technique whereby expired gases will be sampled and analysed alongside and blood pressure measurements.
optional (for non-IST participants only)
Assessment of ANS function in pregnant women with and without IST, at rest and during mild exercise
Blood Pressure in mm/Hg
Time frame: Up to 3 years