Stress is indeed bad for your heart!

Reply to Karthik Viswanathan: What is the link between psychologic stress, caffeine, sympathetic activity and ventricular ectopics?

Mohan Shanmugam, Anesthesia & Intensive Care, Abertawe Bro Morgannwg University NHS Trust, Swansea, UK; E-mail: mohan at intubator dot co dot uk

Received, accepted and published 27 April 2008

There appears to be adequate clinical, laboratory and cellular evidence that suggests that psychologic stress is arrhythmogenic. It is presumably related to the sympathetically mediated catecholamine surge [1-3]. Essentially, the mechanism is related to the activation of sodium-potassium-ATPase pump causing redistributional hypokalemia. The resulting hyperpolarisation of cardiac muscle cells predisposes to ventricular arrhythmias.

While a relationship between caffeine intake and ventricular ectopics is anecdotally presumed, there is inconsistent evidence in this area. It seems caffeine, when consumed in moderate amounts (~200 mg/day), causes a relatively insignificant increase in catecholamines [4].

The clinical management of ventricular ectopics and the current evidence base is very well summarised in a recent paper by Ng [5].

Conflict of interests: none declared.


References:

1. Tisdale JE, Patel RV, Webb CR, Borzak S, Zarowitz BJ. Proarrhythmic effects of intravenous vasopressors. The Annals of Pharmacotherapy. 1995; 29: 269-281 available online at http://www.theannals.com/cgi/content/abstract/29/3/269, accessed 27 April 2008

2. Clausen T and Everts ME. Regulation of the Na, K pump in skeletal muscle. Kidney International 1989; 35: 1–13. Full text article at http://www.nature.com/ki/journal/v35/n1/pdf/ki19891a.pdf accessed 27 April 2008

3. Macdonald JE and Struthers AD. What is the optimal serum potassium level in cardiovascular patients? Journal of the American College of Cardiology 2004; 43: 155-161; full text at http://content.onlinejacc.org/cgi/content/full/43/2/155 accessed 27 April 2008

4. Myers MG. Caffeine and cardiac arrhythmias. Chest 1988; 94: 4–5, full text at http://www.chestjournal.org/cgi/reprint/94/1/4.pdf accessed 27 April 2008

5. Ng GA. Treating patients with ventricular ectopic beats. Heart 2006; 92:1707-1712; extract at http://heart.bmj.com/cgi/content/extract/92/11/1707 accessed 27 April 2008

Reviewed by E.S.Prakash, Editor, Medical Physiology Online