Sympathetic and Vascular Function in Takotsubo Syndrome

Female Takotsubo patients included in the SAFT (sympathetic and vascular function in Takotsubo syndrome) study will be invited to undergo microneurography recording of muscle sympathetic nerve activity (MSNA) at rest and during stress one week to two month after study inclusion. Responses to stress with and without the commonly used betablocking agent metoprolol will be compares.

Microneurography will be performed in the morning after a light caffeine-free breakfast with the subject supine and awake. Any medication with a beta blocking agent will be discontinued 24 hours prior to examination. MSNA will be recorded by inserting a tungsten electrode into the sympathetic nerve fibres of the peroneal nerve, with simultaneous blood pressure and heart rate monitoring.

MSNA recording will then continue during stress induced by placing one of the subjects hand in ice-cold water for 90 seconds (cold pressor test).

After intravenous injection with beta blocking agent (metoprolol) or placebo (saline) in a 1:1 randomized fashion, MSNA recording at rest and during stress will be repeated.

Age- and gender-matched healthy volunteers will be recruited as controls and examined similarly with microneurography at rest and during stress.

MSNA recordings will be amplified, computerized and saved for further analyses. MSNA will be quantified as burst incidence (burst per 100 heartbeats), burst frequence (bursts per minute) and relative median burst amplitude (%). MSNA activity will be compared between Takotsubo patients and controls and before and after betablockade in Takotsubo patients.

Inclusion criteria

For patients:

• Diagnosis of Takotsubo cardiomyopathy

For Controls:

• Matching age with Takotsubo patients
• Signed informed consent

Exclusion criteria

• Coronary anathomy precluding intracoronary investigations
• Severe obstructive pulmonary disease
• Kidney failure with estimated glomerular filtration rate < 30 ml/min/m2
• Active malignancy
• Pericarditis