In their rapid response Carlos Escobar, Rocio Echarri, and Vivencio
Barrios asked whether an increase in heart rate might be a cause or effect
of coronary events in women (1). It may indeed be an effect a rise in
pulse rate being, from a metabolic perspective, an indication of the need
to deliver more nutrient to meet the metabolic demands of the tissues at
the time. A rise in blood catecholamines, a rise in fasting blood sugar
and a rise in blood pressure (2) might all be interpreted in the same way.
An acute coronary event might only be a cause if it compromises
myocardial function to the degree that it impairs, or compounds an
impairment of, the systemic energy supply/demand. But this might be highly
unusual the low cardiac output syndrome being a productive, rather than a
harmful endogenous response to the acute coronary event in tyhat it
decreases myocaridla workload. In which case a fall in catecholamines,
fasting blood sugar and even blood pressure might all be interpreted as
evidence of an improvement in systemic tissue energy supply/demand rather
than the reverse. If so decreasing cardiac output, or rather allowing it
to fall, may be a far more desirable therapeutic objective in an acute
coronary event than the conventional attempts of actively increasing it
with fluids and inotropes. By increasing myocardial workload the latter
might even increase the risk of myocardial failure and sudden cardiac
death.
1. Women, heart rate and coronary disease. Cause or consequence?
Carlos Escobar, Rocio Echarri, Vivencio Barrios (9 February 2009)
2. Systolic blood pressure -- Basile 325 (7370): 917 -- BMJbmj.com,
28 Oct 2002 [Full text]; Hypertension: product of mitochondrial
dysfunction? Richard G Fiddian-Green bmj.com, 1 Nov 2002 [Full text] ... www.bmj.com/cgi/content/full/325/7370/917
Rapid Response:
Tachycardia: cause or effect?
In their rapid response Carlos Escobar, Rocio Echarri, and Vivencio
Barrios asked whether an increase in heart rate might be a cause or effect
of coronary events in women (1). It may indeed be an effect a rise in
pulse rate being, from a metabolic perspective, an indication of the need
to deliver more nutrient to meet the metabolic demands of the tissues at
the time. A rise in blood catecholamines, a rise in fasting blood sugar
and a rise in blood pressure (2) might all be interpreted in the same way.
An acute coronary event might only be a cause if it compromises
myocardial function to the degree that it impairs, or compounds an
impairment of, the systemic energy supply/demand. But this might be highly
unusual the low cardiac output syndrome being a productive, rather than a
harmful endogenous response to the acute coronary event in tyhat it
decreases myocaridla workload. In which case a fall in catecholamines,
fasting blood sugar and even blood pressure might all be interpreted as
evidence of an improvement in systemic tissue energy supply/demand rather
than the reverse. If so decreasing cardiac output, or rather allowing it
to fall, may be a far more desirable therapeutic objective in an acute
coronary event than the conventional attempts of actively increasing it
with fluids and inotropes. By increasing myocardial workload the latter
might even increase the risk of myocardial failure and sudden cardiac
death.
1. Women, heart rate and coronary disease. Cause or consequence?
Carlos Escobar, Rocio Echarri, Vivencio Barrios (9 February 2009)
2. Systolic blood pressure -- Basile 325 (7370): 917 -- BMJbmj.com,
28 Oct 2002 [Full text]; Hypertension: product of mitochondrial
dysfunction? Richard G Fiddian-Green bmj.com, 1 Nov 2002 [Full text] ...
www.bmj.com/cgi/content/full/325/7370/917
Competing interests:
None declared
Competing interests: No competing interests