From the Guidelines
Yes, a 66-year-old patient with recurrent atrial fibrillation with rapid ventricular response (AFib with RVR) who has already received three doses of diltiazem can receive additional boluses and be placed on a diltiazem drip. The typical approach would be to administer another IV bolus of diltiazem (0.25 mg/kg, approximately 15-20 mg) followed by initiation of a continuous infusion at 5-15 mg/hour, titrated to achieve heart rate control (typically aiming for <110 beats per minute) 1. Close monitoring of blood pressure, heart rate, and cardiac rhythm is essential during this treatment. The patient should be on continuous cardiac monitoring, with frequent vital sign checks (every 15 minutes initially, then every 30-60 minutes once stable). Diltiazem works by blocking calcium channels in the atrioventricular node, which slows conduction and controls ventricular rate without necessarily converting the patient back to normal sinus rhythm. Be cautious with diltiazem in patients with heart failure, hypotension, or those on beta-blockers due to potential additive effects. If the patient develops hypotension or bradycardia during treatment, the infusion rate should be reduced or temporarily discontinued. It is also important to consider the patient's overall clinical context, including their medical history, current medications, and any potential contraindications to diltiazem therapy, as outlined in recent guidelines for the management of atrial fibrillation 1. The most recent guidelines from 2024 emphasize the importance of integrated AF care, including patient involvement and empowerment, educational guidance, and shared decision-making 1. In terms of specific treatment recommendations, the guidelines suggest that rate control therapy should be used to control heart rate and symptoms, and that diltiazem is a suitable option for this purpose 1. Overall, the decision to administer additional boluses and start a continuous infusion of diltiazem should be made on a case-by-case basis, taking into account the individual patient's needs and circumstances.
From the FDA Drug Label
In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy. Atrial fibrillation or atrial flutter In clinical studies with diltiazem hydrochloride injection for AF/Fl, 135 of 257 patients were over 65 years of age No overall differences in safety or effectiveness were observed between these patients and younger patients, and other reported clinical experience has not identified differences in responses between the elderly and younger patients, but greater sensitivity of some older individuals cannot be ruled out
The patient can be given boluses of Diltiazem and started on a continuous infusion if they revert to atrial fibrillation (AFib) with rapid ventricular response (RVR), but dose selection should be cautious, usually starting at the low end of the dosing range 2.
- Key considerations for the elderly patient include:
- Decreased hepatic, renal, or cardiac function
- Concomitant disease or other drug therapy
- Greater sensitivity of some older individuals cannot be ruled out It is essential to monitor renal function and exercise care when treating patients with multiple medications.
From the Research
Diltiazem Administration for Atrial Fibrillation
- The patient in question is a 66-year-old with atrial fibrillation (AFib) and rapid ventricular response (RVR) who required three doses of Diltiazem for conversion 3.
- According to the study by 3, low-dose diltiazem might be as effective as the standard dose in controlling rapid AF and reduce the risk of hypotension.
- Another study 4 found that calcium chloride pre-treatment before i.v. diltiazem did not significantly blunt the systolic blood pressure drop, but it may be equally safe compared to placebo as a pre-treatment in the management of AF with RVR.
Boluses and Continuous Infusion of Diltiazem
- If the patient reverts to atrial fibrillation with rapid ventricular response, boluses of Diltiazem and a continuous infusion may be considered, as the patient has already received three doses of Diltiazem for conversion 3.
- A study comparing intravenous metoprolol and diltiazem for AFib with RVR found that diltiazem reduced heart rate more quickly and reduced heart rate by 20% or greater more frequently than metoprolol with no safety outcome differences 5.
- Another study found that there was no difference in achieving rate control when using intravenous diltiazem, metoprolol, or verapamil, but further studies are needed to determine which agent is superior for rate control 6.
Considerations for Heart Failure Patients
- For patients with concomitant heart failure with reduced ejection fraction (HFrEF), the American Heart Association notes that calcium channel blockers like diltiazem should be avoided due to their potential negative inotropic effects 7.
- However, a study comparing the incidence of adverse effects in HFrEF patients treated with IV diltiazem or metoprolol found that there was no difference in total adverse events, but the diltiazem group had a higher incidence of worsening heart failure symptoms 7.