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Hemodynamic effects of intravenous diltiazem in patients treated chronically with propranolol
Insights
Acute intravenous diltiazem administration was safe in patients with coronary heart disease on beta blockers. This treatment prevented negative hemodynamic effects like increased vascular resistance and decreased cardiac output.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Beta blockers are commonly used for chronic coronary heart disease.
- Potential for adverse hemodynamic effects exists with beta blocker therapy.
Purpose of the Study:
- To evaluate the hemodynamic effects of acute intravenous diltiazem in patients with coronary heart disease on beta blockers.
- To determine if diltiazem prevents deleterious effects associated with beta blockers.
Main Methods:
- Two groups of eight patients with coronary heart disease and no heart failure were studied.
- Group 1 received no prior treatment; Group 2 received long-term propranolol.
- Hemodynamic parameters were measured after intravenous diltiazem (0.25 mg/kg) administration.
Main Results:
- In untreated patients, diltiazem decreased systemic vascular resistance and increased cardiac index.
- In propranolol-treated patients, diltiazem increased cardiac index and systolic index, and decreased systemic vascular resistance and mean blood pressure.
- These beneficial effects persisted for at least 15 minutes.
Conclusions:
- Intravenous diltiazem is safe in patients with coronary heart disease on propranolol.
- Diltiazem effectively counteracted potential negative hemodynamic effects of beta blockers, such as increased peripheral vascular resistance and reduced cardiac output.
Abstract:
In the search for any deleterious hemodynamic effects of the acute administration of intravenous diltiazem (0.25 mg/kg), in patients on beta blockers, studies were performed in two comparable groups of eight patients with chronic coronary heart disease without clinical signs of heart failure. In the first group, with no previous treatment, the only significant variations observed were a decrease in systemic vascular resistance (p less than 0.01) and an increase in cardiac index (p less than 0.01), which were noted only at 5 minutes. In the second group, receiving long-term oral doses of 120 to 240 mg/day of propranolol, at 5 minutes, despite a slight decrease in peak positive first derivative of left ventricular pressure (p less than 0.05), cardiac index and systolic index increased (p less than 0.05 and p less than 0.01) with decreases in systemic vascular resistance (p less than 0.01) and mean blood pressure (p less than 0.05); at 15 minutes, systemic vascular resistance was still decreased (p less than 0.05) and cardiac index and systolic index were still increased (p less than 0.05). In conclusion, intravenous administration of diltiazem (0.25 mg/kg) to patients with chronic coronary heart disease and no evidence of congestive heart failure, who were receiving propranolol, was safe and prevented, in these patients, the potential deleterious effects of beta blockers, that is, increased peripheral vascular resistance and decreased cardiac output.