Introduction:

The consumption of yerba mate (YM) (Ilex paraguariensis) is common in South America and is now used all over the world. It contains many bioactive substances that can be beneficial. There is also the opinion that it may have harmful effects on heart rhythm, but no studies have been found on this.

Objective:

The aim of this study was to evaluate the acute effect of YM on heart rhythm in patients referred for a Holter study.

Method:

A before and after pseudo-experimental clinical study was conducted by performing a Holter on 50 habitual users of YM, and another one after 24 without YM consumption. The use of other products that could interfere was also controlled.

Results:

The mean age of the subjects was 55 ± 15 years, and 52% were women. At least one vascular risk factor was found in 78%, with 44% structural heart disease, and 90% taking cardio- vascular medication. The heart rate (HR) with and without YM was similar. Only the minimum hourly HR was lower when taking YM (61 ± 10 vs. 63 ± 9, P = .021). There was no significant diffe- rence in the incidence of sustained or non-sustained arrhythmias, or in ventricular extrasystoles. The total number of supra-ventricular premature beats was higher without YM (952 ± 3,538 vs. 1,294 ± 5,201, P = .014) and also the maximum hourly (86 ± 302 vs. 107 ± 360, P = .032). There was no difference in HR variability.

Conclusions:

In cardiology patients, usual users of YM, habitual consumption was not associated with significant changes in HR or an increase in the incidence of arrhythmias. There was less ectopic supraventricular activity.