Ability of calcium-entry blockade by felodipine to disclose different pathogenetic mechanisms behind hyperventilation-induced myocardial ischemia in men.
To verify that myocardial ischemia occurring during either the overbreathing or recovery phase of the hyperventilation test is based on different pathogenetic mechanisms, 2 consecutive series of patients, selected on the basis of their response to a run-in hyperventilation test, were studied. Group I comprised 15 patients who developed ST-segment depression early during overbreathing, whereas group II consisted of 12 patients showing ST-segment depression late during the recovery phase. A single oral dose of felodipine 10 mg or of placebo was administered on 2 consecutive days according to a randomized, double-blind, crossover design, and the hyperventilation test was repeated, on both days of the study, 3 to 5 hours after drug intake. In group I, ST-segment depression occurred after placebo in all patients during overbreathing, with an increase in rate pressure product (from 112 +/- 31 at baseline to 168 +/- 55 mm Hg x beats/min/100 at the onset of ST-segment depression; p less than 0.01). After felodipine, 13 patients continued to show ST-segment depression during overbreathing, together with an increase in rate pressure product (from 107 +/- 24 at baseline to 158 +/- 46 mm Hg x beats/min/100 at the onset of electrocardiographic changes; p less than 0.01). In group II, all 12 patients showed ST-segment depression during recovery after placebo, with a rate pressure product comparable to baseline conditions (112 +/- 35 at baseline vs 102 +/- 27 mm Hg x beats/min/100 at the onset of ST-segment depression; difference not significant). After felodipine, no patient developed ST-segment depression or chest pain.(ABSTRACT TRUNCATED AT 250 WORDS)
Ardissino
D
D
Division of Cardiology, IRCCS, Policlinico S. Matteo, University of Pavia, Italy.
Savonitto
S
S
Zanini
P
P
Barberis
P
P
De Servi
S
S
Rolla
A
A
Specchia
G
G
D017023:Coronary Angiography; D003327:Coronary Disease / Q000175:diagnosis* / Q000209:etiology; D003331:Coronary Vessels / Q000187:drug effects; D004311:Double-Blind Method; D004562:Electrocardiography; D015736:Felodipine / Q000097:blood; D006801:Humans; D006985:Hyperventilation / Q000150:complications*; D008297:Male; D008875:Middle Aged
D015736:Felodipine