None listed
Conditions
Brief summary
This study will compare how a 24 hour continuously recorded ECG of 12 women with a history of broken heart syndrome compares to 12 women with a history of non-ST elevation acute coronary syndrome when exposed to a controlled stressful environment (voluntary hyperventilation) or control stressful environment (diaphragmatic breathing) for 3 minutes. Emphasis will be placed on the QT interval change during the 3 minutes, and the QT interval change and heart rate variability in the 24 hours immediately post-intervention/control. There is a cross-over design, with at least one week between each recording period.
Interventions
Breathing exercises will be performed with the participant seated.
3 minutes of voluntary hyperventilation: the participant will be asked to consciously breathe deeper and faster for three minutes. Hyperventilation will be performed in a supervised setting. It is an autonomic nervous system stimulus that does not involve physical activity, the patient is seated. We are using it in this study in this manner as we will be able to accurately know the timing and can therefore correlate any autonomi
Breathing exercises will be performed with the participant seated. 3 minutes of voluntary hyperventilation: the participant will be asked to consciously breathe deeper and faster for three minutes. Hyperventilation will be performed in a supervised setting. It is an autonomic nervous system stimulus that does not involve physical activity, the patient is seated. We are using it in this study in this manner as we will be able to accurately know the timing and can therefore correlate any autonomic changes seen on the ECG recording. Voluntary hyperventilation can cause a feeling of mild anxiety. The mild anxiety that may result is at a level similar to what may be encountered in normal everyday life. There is no specific risk from this. The supervisor will discontinue the hyperventilation if this develops. Hyperventilation may also cause a dry mouth as a direct effect of increased air flow. The supervisor will discontinue the exercise if the participant notes a dry mouth. Drinking water will also be available. The ECG will be recorded continuously for 24 hours from the start of the intervention with a Holter monitor. The monitor will be fitted by one of the study authors trained in fitting the monitor. The patient will be phoned three times during the 24 hour period to ensure adherence and to take a 20 question emotional survey. The monitor is worn on two occasions with a one week washout period between.
Sponsors
Dr Paul Bridgman
Study design
Allocation
Randomised controlled trial
Intervention model
Crossover
Primary purpose
Diagnosis
Masking
Blinded (masking used) (Subject, Outcomes Assessor)
Eligibility
Sex/Gender
All
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
Twenty four women with a past history of admission to hospital with either takotsubo syndrome or a non –ST elevation acute coronary syndrome (NSTEACS). There will be twelve in each group. Takotsubo syndrome will be defined according to modified-Mayo criteria. That is a hospital presentation with a troponin elevation, a recognised regional wall motion pattern that fully resolves and absence of culprit coronary artery disease on coronary angiography. Non-ST elevation acute coronary syndrome is defined as a hospital presentation with either unstable angina or non-ST elevation myocardial infarction.
Exclusion criteria
Impaired left ventricular function (LVEF <50%) Current therapy with beta blockade History of panic disorder Atrial fibrillation Left bundle branch block
Outcome results
None listed