Key result
Intravenous administration of 10mg dl-propranolol resulted in rapid myocardial uptake within 5 minutes followed by release, alongside early increases in heart rate and left ventricular dp/dt maximum.
Why the study?
How does intravenous dl-propranolol affect myocardial uptake and cardiac performance over time in patients with ischaemic heart disease?
How does intravenous dl-propranolol affect myocardial uptake and cardiac performance over time in patients with ischaemic heart disease?
Intravenous propranolol exhibits rapid myocardial uptake and subsequent release within 5 minutes, suggesting the presence of numerous unspecific binding sites in the human heart.
Case report data should not guide propranolol dosing in ischaemic heart disease; leaves open the role of unspecific myocardial binding sites.
The temporal relationship between the myocardial arteriovenous difference of plasma propranolol concentration and heart rate and left ventricular dp/dt maximum was examined for 30 min after intravenous administration of 10mg (0.04 mmol) dl-propranolol in nine patients with ischaemic heart disease. 2. Very large positive myocardial a.v. differences of propranolol within the first 5 min became negative after 5 min, indicating a rapid, avid uptake with subsequent release of propranolol from the heart. 3. The heart rate and left ventricular dp/dt maximum increased 1 min after propranolol administration and did not change after the fifth min of the observation period. 4. The data suggest that a large number of unspecific binding sites for propranolol are present in the heart in addition to the specific beta-receptors.
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Hesse et al. (1979) studied ischaemic heart disease (n=9). dl-propranolol was evaluated on Temporal relationship between myocardial arteriovenous difference of plasma propranolol concentration and heart rate and left ventricular dp/dt maximum. Intravenous administration of 10mg dl-propranolol resulted in rapid myocardial uptake within 5 minutes followed by release, alongside early increases in heart rate and left ventricular dp/dt maximum.
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