In demand mode, it will stimulate the heart only if the heart rate is less than the pacemaker's set programmed rate. Then you'll increase the output until pacing is achieved. After TCP begins, Mr. Young improves dramatically. With Mr. Young stabilized, you prepare him for transfer to the CCU, where a transvenous pacemaker will be inserted. In those situations, the physician would typically have ordered dopamine I.V. as a bridge to transvenous pacing.
Dopamine exerts a strong sympathetic effect on the heart and peripheral blood vessels.
A dopamine infusion may increase heart rate, enhance myocardial contractility, improve cardiac output, and raise blood pressure. If your patient has severe bradycardia with extreme hypotension, the physician may order an epinephrine infusion instead of dopamine because of epinephrine's greater effectiveness. If the patient doesn't respond to atropine, TCP, dopamine, or epinephrine, the physician may order an isoproterenol infusion. But he'll order this drug with caution because it greatly increases myocardial oxygen needs and can induce or worsen myocardial ischemia. It can also increase the risk of ventricular tachycardia and fibrillation.