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Haemodynamic and catecholamine response to simulated ventricular tachycardia in man: effect of baseline left
T M Kolettis1, E Psarros, Z S Kyriakides
1Department of Cardiology, University of Ioannina, Ioannina, Greece. thkolet@cc.uoi.gr
Objective:
To examine the effects of baseline left ventricular function on the haemodynamic and catecholamine responses to ventricular tachycardia.
Design:
Experimental cohort study.
Setting:
Cardiac catheterisation laboratory in tertiary referral centre.
Subjects:
24 patients (19 male, 5 female; mean (SD) age, 59 (10) years) without coronary artery disease, divided into two groups with normal or impaired left ventricular function: group A, ejection fraction > 65% (n = 10); group B, ejection fraction < 45% (n = 14). Other medical and demographic factors were similar in the two groups.
Interventions:
Ventricular tachycardia was simulated with rapid pacing at 150 beats/min for 10 minutes.
Main Outcome Measures:
Arterial blood pressure; venous plasma catecholamine concentrations.
Results:
During rapid pacing, blood pressure was lower in group B (with impaired left ventricular function) than in group A: systolic blood pressure, 102 (11) v 115 (9) mm Hg (p = 0.005); mean blood pressure, 79 (6) v 85 (6) mm Hg (p = 0.02). The ejection fraction correlated with the lowest systolic blood pressure (r = 0.64, p = 0.0006). Although the rise in adrenaline was comparable between the two groups, the rise in noradrenaline was more pronounced (p < 0.05) in patients in group B.
Conclusion:
At low rates and in selected patients, the underlying state of left ventricular function affects haemodynamic tolerance of ventricular tachycardia. Patients with impaired left ventricular function have a lower blood pressure during ventricular tachycardia, despite an exaggerated noradrenaline release.
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