Postischemic left ventricular dysfunction is abolished by alpha-adrenergic blocking agents.

Abstract

OBJECTIVES:

We sought to evaluate the efficacy of alpha-adrenergic blocking agents in counteracting left ventricular (LV) dysfunction occurring after transient ischemia in humans.

BACKGROUND:

The mechanisms underlying postischemic LV dysfunction are largely unknown.

METHODS:

Percutaneous transluminal coronary angioplasty (PTCA) provides a clinical model of ischemia and reperfusion. In 50 patients undergoing coronary stenting for 77+/-5% stenosis, LV function was monitored by transesophageal echocardiography during and 30-min after PTCA. Fifteen minutes after stenting, 15 patients received 12 microg/kg body weight of the alpha-blocker phentolamine intracoronarily, 15 patients received 600 microg/kg of the alpha1-blocker urapidil intravenously, 10 patients received the combination of phentolamine and 1.2 mg of propranolol intracoronarily, and 10 patients received saline.

RESULTS:

Fifteen minutes after successful coronary dilation, significant contractile dysfunction occurred in previously ischemic and nonischemic myocardium. LV dysfunction was accompanied by an increase in coronary resistance and diffuse vasoconstriction. Alpha-blockers counteracted LV dysfunction and coronary resistance and the increase in vasoconstriction. Phentolamine and urapidil increased global LV shortening from 34+/-9% to 45+/-8% and to 49+/-8%, respectively (p < 0.05). After the administration of propranolol combined with phentolamine, LV dysfunction remained unchanged (34+/-6%), as in control subjects.

CONCLUSIONS:

LV dysfunction occurs after PTCA, as described in animal models after ischemia. Alpha-blockers abolished LV, macrocirculatory and microcirculatory dysfunction, whereas the alpha-blocker effect was prevented by combining alpha- and beta-blockers. The evidence of diffuse rather than regional dysfunction, together with the opposite effects of alpha- and beta-blockade, supports the hypothesis of neural mechanisms eliciting postischemic LV dysfunction.

• Authors: L Gregorini, J Marco, C Palombo, M Kozàkovà, G B Anguissola, B Cassagneau, M Bernies, A Distante, I Marco, J Fajadet, A Zanchetti
• Journal: Journal of the American College of Cardiology (J Am Coll Cardiol) Vol. 31 Issue 5 Pg. 992-1001 (Apr 1998) ISSN: 0735-1097 [Print] United States
• PMID: 9561999 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Adrenergic alpha-Antagonists

Topics

• Adrenergic alpha-Antagonists (pharmacology, therapeutic use)
• Aged
• Angioplasty, Balloon, Coronary
• Coronary Vessels (diagnostic imaging)
• Echocardiography, Transesophageal
• Female
• Hemodynamics (drug effects)
• Humans
• Male
• Middle Aged
• Myocardial Ischemia (complications, physiopathology, therapy)
• Stents
• Vascular Resistance (drug effects)
• Ventricular Dysfunction, Left (diagnostic imaging, drug therapy, etiology)