Diltiazem is a calcium channel blocker prescribed for various cardiovascular conditions, including high blood pressure and chest pain. It helps regulate heart function.
How Diltiazem Affects Heart Rate
Diltiazem, a non-dihydropyridine calcium channel blocker, primarily acts on L-type calcium channels in cardiac muscle and the heart’s electrical conduction system. By inhibiting calcium ion influx during depolarization, it directly impacts how the heart generates and transmits electrical signals.
This action is particularly notable at the sinoatrial (SA) node, the heart’s natural pacemaker, and the atrioventricular (AV) node, which relays electrical impulses. By slowing conduction through the AV node, diltiazem reduces ventricular contractions, lowering heart rate. It also has a negative chronotropic effect, decreasing heart rate and managing tachycardia without causing excessive bradycardia in those with elevated baseline rates.
Medical Uses for Heart Rate Control
Diltiazem manages rapid or irregular heartbeats, commonly treating atrial arrhythmias like atrial fibrillation and atrial flutter. In these conditions, the heart’s upper chambers beat chaotically or too rapidly. Diltiazem helps control the ventricular rate by slowing electrical impulses to the lower chambers.
The medication is also prescribed for paroxysmal supraventricular tachycardia (PSVT), an abnormally fast heart rhythm originating above the ventricles. Beyond rhythm control, diltiazem manages angina. It reduces the heart’s oxygen demand by decreasing heart rate, blood pressure, and the force of cardiac contractions, easing the heart’s workload.
Important Considerations for Patients
Patients taking diltiazem should regularly monitor their heart rate and blood pressure. Healthcare providers may advise daily pulse checks, with reporting if it falls below a certain rate. This monitoring helps ensure the medication’s effectiveness and prevents unintended effects.
While generally well-tolerated, diltiazem can cause side effects like dizziness, headache, and fluid retention. It may also lead to bradycardia or low blood pressure. Symptoms of a heart rate that is too low include lightheadedness, confusion, weakness, fatigue, or shortness of breath. If these occur, or if severe dizziness develops, seek medical attention.
Diltiazem should be used cautiously in patients with heart failure, as it can worsen the condition. Combining it with other heart rate medications, such as beta-blockers, requires careful consideration due to potential additive effects. Adhering to a physician’s instructions is crucial for safe and effective use.