Medical Matters: Want to reduce risk of heart attack? Take that afternoon nap

 

The annual congress of the European Cardiac Society is the premier event when it comes to the latest research news in cardiovascular disease.

Last week’s meeting in London was no exception and although I didn’t make it in person, a daily menu of press releases kept me up to date. As always there was a selection of more esoteric research, a smorgasbord of which I will write about in today’s column.

Those of you who enjoyed a Mediterranean holiday this year and who joined the locals in having an agreeable daily siesta may wish to continue the practice, according to Greek researchers.

The prospective study of more than 380 people (average age 61 years) with well-controlled hypertension found that those who slept for at least an hour in the middle of the day had a 4mm of mercury (Hg) lower systolic blood pressure than those who did not have a daytime nap. The well-designed study relied on 24-hour blood pressure readings and adjusted for potential confounding factors such as smoking, salt and coffee intake and exercise.

Lead author Dr Manolis Kallistratos noted that a blood pressure reduction of just 2mm Hg may decrease the relative risk of a cardiac event by up to 10 per cent.

Commenting on the results, consultant cardiologist Prof Ian Graham of Trinity College Dublin and Tallaght hospital told online journal MedPage Today: “It’s not a trial, it’s observational, but it’s quite a big effect and could very well be genuine.”

Higher rates

For those of us with pre-existing cardiovascular disease there was a warning of higher rates of harmful future vascular events in the presence of depression and extremes of blood pressure.

The Scottish study of more than 35,000 patients found that the risk of further stroke or heart attack, heart failure or dying due to heart disease was 83 per cent higher in depressed patients with high blood pressure and 36 per cent higher in depressed patients with low blood pressure, compared with those with normal blood pressure and no depressive symptoms.

Dr Bhautesh Jani of the University of Glasgow and colleagues followed the patients with previous heart disease, stroke or diabetes in the community for four years; overall just over one in 10 had a further cardiovascular event during that time.

Prof Graham urged a cautious interpretation: “Maybe it’s a slight chicken and egg [situation] because are they depressed because they’ve had an event? Or do they get another event because they are depressed?” he said. “There seems to be some kind of synergy. Whatever that means we don’t know, because there’s no good evidence that treating depression lowers risk.

“But it should be a signal to try harder with ordinary risk factors – to try harder on blood pressure, cholesterol, and smoking in somebody who has had an event and is depressed,” he added.

Climates

We haven’t had the best of summers weather-wise this year, but at least our climate is temperate.

Winnipeg in Canada is one of the coldest large cities in the world and is an ideal place to study the effect of temperature on cardiac events. Which is what Dr James Tan and colleagues of the University of Manitoba did in a look-back study of some 1,800 patients who had been admitted to hospital with a heart attack.

They found that with every drop of 10 degrees Celsius in the daily high temperature mark, the risk of heart attack increased by 7 per cent, with the risk predictable up to two days before the actual heart attack.

The finding is probably due to the increased viscosity and greater coagulability of blood in colder weather.

But as Crowded House remind us in the chorus of their hit song –“Everywhere you go, always take the weather with you” – there is not a lot we can do about weather as a cardiac risk factor.

mhouston@irishtimes.com

muirishouston.com

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