Plasma catecholamihe concentrations in pacing induced angina

Muiesan, G; Valori, C; Agabiti‐Rosei, Enrico; Nigri, A; Gioffrè, Pier Agostino; Motolese, M; Reale, A

doi:10.1016/0002-9149(73)90962-4

Cited by 2 publications

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“…These latter properties, in combination with the masking of its beneficial effects (i.e., reduction of heart rate and cardiac work) by pacing, may explain why propranolol was ineffective in this rabbit model. Similarly, Muiesan et al (16) reported that beta-adrenergic blockade with oxprenolol failed to inhibit the severity and duration of pain precipitated by atrial pacing in anginal patients.…”

Section: Fig 2 Ecg Tracings From An Atherosclerotic Rabbit Intrinsmentioning

confidence: 96%

Effects of Several Antianginal Agents on Pacing-Induced S-T Segment Depression in the Atherosclerotic Rabbit

Baky¹,

Lee²

1975

Experimental Biology and Medicine

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Increasing myocardial demand for oxygen by right atrial pacing causes ischemic S-T segment depression in the electrocardiogram of the unanesthetized, atherosclerotic rabbit (1). Unlike the S-T segment depression induced in the same animal model by administration of ergonovine (2) or by "anoxia" due to breathing an atmosphere containing 10 % oxygen (3), the S-T depression induced by atrial pacing was prevented by prior administration of nitroglycerin, but not of dipyridamole. The present study describes the effects of several clinically tested antianginal agents, including chromonar, papaverine, pentaerythritol tetranitrate, isosorbide dinitrate, and propranolol, on pacinginduced S-T segment depression in the same animal mqdel.Methods. The methods employed were the same as those previously described (1). Male New Zealand white rabbits, 2 kg, were fed a diet containing 2 % cholesterol for 10-14 wk. At that time, a 14 g polyvinyl chloride catheter was implanted in the right external jugular vein under local anesthetic. Twenty-four hours later, a bipolar pacing electrode was passed into the right atrium of the unanesthetized, catheterized animal. Surface leads were placed on the spine and sternum for recording the electrocardiogram (ECG) on a direct-writing recorder and on magnetic tape for subsequent computer analysis. Stimuli were supplied at approximately one and half times threshold voltage at a frequency of at least 100 beats/min greater than the rabbit's intrinsic heart rate, to a maximum of 420 beats/min. Readings were taken every 15 sec during the 90-sec pacing period. When two successive reproducible episodes of S-T segment depression of at least 0.5 mm (sensitivity = 1 mV/cm) at a given pacing rate were obtained, a drug was administered via the marginal vein of the left ear. Pacing at the same rate as during control periods was instituted at 1, 5, and 30 min after drug administration to determine if protection against S-T segment depression occurred.The drugs tested in these experiments were chromonar (2, 4 mg/kg; dissolved in water), papaverine (0.5, 1 mg/kg; water), pentaerythritol tetranitratel (Peritrate, 250, 500 pg/ kg ; polyethylene glycol-400), isosorbide dinitrate2 (25-600 pg/kg; dilute polyethylene glycol-400) , and propranolo13 (Inderal, 100-500 pg/kg; water).The statistical significance of the effect of each drug on the response to pacing was determined by Student's t test (4).Results. Of the agents tested in this study, only isosorbide dinitrate (ISD) protected against the S-T segment depression induced by pacing. The magnitudes of the pacinginduced S-T segment depression in 13 animals were compared before and after administration of the various doses of ISD (Fig. 1). The mean values of S-T segment depression 1 SEM for each 15-sec period are plotted for 26 control pacing periods; these control depressions averaged 0.91 =t 0.07 mm at 90 sec. Standard errors are shown at the 90-sec reading for the various doses of the drug. The protection afforded by pretreatment with ISD was dose-related, with a...

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Section: Fig 2 Ecg Tracings From An Atherosclerotic Rabbit Intrinsmentioning

confidence: 96%

Effects of Several Antianginal Agents on Pacing-Induced S-T Segment Depression in the Atherosclerotic Rabbit

Baky¹,

Lee²

1975

Experimental Biology and Medicine

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Effect of chronic administration of perhexiline on pacing-induced S-T segment depression in the atherosclerotic rabbit

Lee¹

1976

Life Sciences

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Plasma catecholamihe concentrations in pacing induced angina

Cited by 2 publications

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Effects of Several Antianginal Agents on Pacing-Induced S-T Segment Depression in the Atherosclerotic Rabbit

Effects of Several Antianginal Agents on Pacing-Induced S-T Segment Depression in the Atherosclerotic Rabbit

Effect of chronic administration of perhexiline on pacing-induced S-T segment depression in the atherosclerotic rabbit

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