Caffeine can send the heart racing, but for some people it may help prevent abnormal heartbeats, according to Australian researchers report which found coffee and tea are safe and may sometimes reduce the frequency of abnormal heart rhythms (arrhythmias).
To see how caffeine affects patients with the common heart rhythm disorder known as atrial fibrillation, Kistler and colleagues looked at eight previously published studies.
The report published (April 16) in the journal JACC: Clinical Electrophysiology suggest that up to 300 milligrams of caffeine a day may be safe for patients with abnormal heartbeats.
In addition, the researchers found that caffeine had no effect on abnormal heartbeats in the lower chambers of the heart, called ventricular arrhythmias.
“Although coffee increases your heart rate, it does not make it abnormal,” explained senior researcher Dr. Peter Kistler, director of electrophysiology at Alfred Hospital and Baker Heart and Diabetes Institute in Melbourne.
“We found that there is no detrimental effects of coffee on heart rhythm and, in fact, coffee at up to three cups per day may be protective,” he added.
Some people, however, may notice palpitations after drinking coffee, and those folks should avoid caffeine, Kistler added.
“We have completed the largest review of the medical literature to date to determine the relationship between coffee and arrhythmias, or abnormal heartbeats,” he said.
Kistler’s group found that, among more than 228,000 patients, drinking coffee cut the frequency of episodes of atrial fibrillation by 6 percent. A further analysis of nearly 116,000 patients found a 13 percent risk reduction.
One cup of coffee contains about 95 milligrams of caffeine and acts as a stimulant to the central nervous system. Caffeine also blocks adenosine, a chemical that can trigger atrial fibrillation, Kistler explained.
As many as six cups of coffee a day, about 500 milligrams of caffeine, did not increase the severity or rate of ventricular arrhythmias, the study authors said.
Moreover, one study of 103 heart attack patients who got about 353 milligrams of caffeine a day found improved heart rate and no significant arrhythmias, according to the new report.
Two studies, however, found an increase in the risk for ventricular arrhythmias among patients who drank as much as nine or 10 cups of coffee a day.
But Kistler’s team did find that patients with heart conditions should avoid caffeinated energy drinks. These drinks can each contain 160 to 500 milligrams of concentrated caffeine.
With Agency Inputs
Suicide can’t be predicted by asking about suicidal thoughts : Study
Most people who died of suicide deny they experience suicidal thoughts when asked by doctors in the weeks and months leading up to their death, a major Australian study has found.
The findings, co-authored by clinical psychiatrist and Professor Matthew Large from UNSW’s School of Psychiatry, Sydney that published in the journal BJPsych Open The meta-analysis challenge the widely-held assumption that psychiatrists can predict who will suicide by asking if they are preoccupied with thoughts of killing themselves.
The study showed that 80% of patients who were not undergoing psychiatric treatment and who died of suicide reported not to have suicidal thoughts when asked by their psychiatrist or GP.
“If you meet someone who has suicidal ideation there is a 98 per cent chance that they are not going to suicide,” said Professor Large, an international expert on suicide risk assessment who also works in the emergency department of a major Sydney hospital.
“But what we didn’t know was how frequently people who go on to suicide have denied having suicidal thoughts when asked directly,” he added.
“This study proves we can no longer ration psychiatric care based on the presence of suicidal thoughts alone. We need to provide high-quality, patient-centred care for everyone experiencing mental illness, whether or not they reveal they are experiencing suicidal thoughts,” Professor Large said.
About one in 10 people will have suicidal ideation in their lifetime. But the study showed suicidal ideation alone was not rational grounds for deciding who gets treatment and who does not, Professor Large said.
“We know that suicide feeling is pretty common and that suicide is actually a rare event, even among people with severe mental illness,” Professor Large added.
Suicidal ideation tells us an awful lot about how a person is feeling, their psychological distress, sometimes their diagnosis and their need for treatment but it’s not a meaningful test of future behaviour.
Suicidal feelings can fluctuate rapidly and people may suicide very impulsively after only a short period of suicidal thoughts.
But, people had good reasons not to disclose thoughts of suicide, fearing stigma, triggering over-reactions or upsetting family and friends, and being involuntarily admitted for psychiatric treatment, Professor Large said.
Professor Large emphasized that clinicians should not assume that patients experiencing mental distress without reporting suicidal ideas were not at elevated risk of suicide.