Is diltiazem (calcium channel blocker) suitable for rate control in atrial fibrillation (AFib) with rapid ventricular response (RVR) in a patient with severe chronic obstructive pulmonary disease (COPD) and right-sided heart failure but normal left ventricular function?

Diltiazem for Atrial Fibrillation with RVR in Severe COPD and Right-Sided Heart Failure

Diltiazem is an appropriate and preferred agent for rate control in atrial fibrillation with rapid ventricular response (RVR) in a patient with severe COPD and right-sided heart failure with preserved left ventricular function. 1

Rationale for Choosing Diltiazem

COPD Considerations

• Beta-blockers, while effective for rate control in most AF patients, can worsen bronchospasm in severe COPD
• The 2014 AHA/ACC/HRS guidelines specifically recommend diltiazem for patients with COPD and AF with RVR 1
• Diltiazem does not cause bronchospasm and is safer in patients with pulmonary disease

Heart Failure Considerations

• For patients with normal left ventricular function, diltiazem is appropriate even with right-sided heart failure 1
• The 2016 ESC guidelines state that non-dihydropyridine calcium channel blockers (like diltiazem) should be avoided only in patients with reduced left ventricular ejection fraction 1
• Since this patient has normal left ventricular function, the negative inotropic effects of diltiazem are less concerning

Administration and Dosing

• Initial dosing:

  • IV administration: 0.25 mg/kg IV over 2 minutes (consider starting with a lower dose of ≤0.2 mg/kg to reduce hypotension risk) 2
  • Oral maintenance: 40-120 mg three times daily 3

• Target heart rate: <110 beats per minute at rest 1

Evidence Supporting Diltiazem Use

• Diltiazem effectively controls ventricular rate both at rest and during exercise 4
• Recent evidence suggests diltiazem may be more effective than metoprolol in achieving rapid rate control in AF with RVR 5
• Low-dose diltiazem (≤0.2 mg/kg) has been shown to be as effective as standard dosing with fewer hypotensive episodes 2

Monitoring and Precautions

• Monitor for:

  • Hypotension (most common adverse effect)
  • Bradycardia
  • Worsening of right heart failure symptoms

• Diltiazem can prolong AV node refractory periods, which may rarely result in abnormally slow heart rates or heart block 6

• Caution with concomitant use of beta-blockers as this may have additive effects on cardiac conduction 6

Alternative Options

If diltiazem is ineffective or poorly tolerated:

• Digoxin may be considered as an alternative, particularly for patients at rest 1
• Amiodarone can be used when other agents are contraindicated or ineffective 1
• AV node ablation with pacemaker implantation for refractory cases 1

Conclusion

For a patient with AF with RVR, severe COPD, and right-sided heart failure with preserved left ventricular function, diltiazem is the preferred agent for rate control. It provides effective rate control while avoiding the bronchospasm risk associated with beta-blockers. Recent evidence supports its safety and efficacy in this clinical scenario, even in patients with right-sided heart failure as long as left ventricular function is preserved.