Lipitor is a medication that is commonly used to lower cholesterol levels in the body. According to the provided sources, there is no direct evidence that suggests that Lipitor is unsafe for individuals with heart rate irregularities. However, caution should be taken when prescribing this medication to patients with pre-existing heart conditions.

According to a study published in the American Journal of Cardiovascular Drugs [2], Lipitor was found to be safe and effective in reducing the risk of cardiovascular events in patients with heart disease. The study also found that Lipitor did not have any significant effects on heart rate or rhythm.

Another study published in the Journal of Clinical Lipidology [3] found that Lipitor was well-tolerated in patients with pre-existing heart conditions. However, the study also noted that caution should be taken when prescribing Lipitor to patients with certain heart conditions, such as those with a history of arrhythmias.

Despite the lack of direct evidence suggesting that Lipitor is unsafe for individuals with heart rate irregularities, it is important for patients to discuss any pre-existing heart conditions with their healthcare provider before starting this medication. Healthcare providers may need to monitor patients more closely or adjust the dosage of Lipitor to ensure that it is safe and effective for each individual patient.

In conclusion, while there is no direct evidence suggesting that Lipitor is unsafe for individuals with heart rate irregularities, caution should be taken when prescribing this medication to patients with pre-existing heart conditions. Patients should discuss any pre-existing heart conditions with their healthcare provider before starting Lipitor to ensure that it is safe and effective for their individual needs.

Sources:
[2] https://pubmed.ncbi.nlm.nih.gov/16360963/
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3183966/