From the Guidelines
Ventricular Tachycardia (VT) does not respond to diltiazem.
Rationale
- Diltiazem is a non-dihydropyridine calcium channel blocker that slows AV node conduction and increases AV node refractoriness, making it effective for treating supraventricular tachycardias (SVTs) but not ventricular tachycardias [ 1 ].
- The American Heart Association guidelines recommend diltiazem for stable, narrow-complex tachycardias, but caution against its use in patients with wide-complex tachycardias, such as VT, unless the arrhythmia is known to be of supraventricular origin [ 1 ].
- For VT, other medications such as procainamide, amiodarone, or sotalol may be considered, but diltiazem is not a recommended treatment option [ 1 ].
- Key characteristics of diltiazem include:
- Initial dose: 15-20 mg (0.25 mg/kg) IV over 2 minutes
- Additional dose: 20-25 mg (0.35 mg/kg) IV in 15 minutes if needed
- Maintenance infusion: 5-15 mg/hour, titrated to heart rate
- It is essential to note that diltiazem should only be given to patients with narrow-complex tachycardias and avoided in patients with heart failure, pre-excited atrial fibrillation or flutter, or rhythms consistent with VT.
From the Research
Response to Ventricular Tachycardia (VT) Treatment with Diltiazem
- The efficacy of diltiazem in treating VT has been studied in various research papers 2, 3, 4, 5, 6.
- A study published in 1992 compared the effects of verapamil and diltiazem on idiopathic VT, finding that both drugs could suppress VT in some patients, with a partial response in others 2.
- Another study from 1985 examined the effects of intravenous diltiazem administration in patients with inducible tachycardia, including one case of VT, and found that diltiazem could interrupt the arrhythmia in all patients 3.
- A 2002 study suggested that calcium channel blockers, including diltiazem, could be effective as a first-line treatment for broad-complex tachycardia with right bundle branch block, including VT 4.
- A 2005 review of calcium channel antagonists, including diltiazem, noted their effectiveness in treating various arrhythmias, including idiopathic left ventricular tachycardia 5.
- A 1995 study compared the efficacy of diltiazem and disopyramide in treating supraventricular tachyarrhythmias, finding that diltiazem was effective in converting paroxysmal atrial tachycardia to sinus rhythm and reducing ventricular response in atrial fibrillation and flutter 6.
Key Findings
- Diltiazem can suppress VT in some patients, with a partial response in others 2.
- Intravenous diltiazem can interrupt VT and other tachycardias 3.
- Calcium channel blockers, including diltiazem, may be effective as a first-line treatment for broad-complex tachycardia with right bundle branch block, including VT 4.
- Diltiazem is effective in treating idiopathic left ventricular tachycardia and other arrhythmias 5.
- Diltiazem can convert paroxysmal atrial tachycardia to sinus rhythm and reduce ventricular response in atrial fibrillation and flutter 6.