What is PAC (Pulmonary Artery Catheter/Premature Atrial Contraction)?

From the Guidelines

PAC can refer to either a Pulmonary Artery Catheter or a Premature Atrial Contraction, which are two entirely different medical concepts. A Pulmonary Artery Catheter is an invasive monitoring device inserted through a central vein and advanced into the pulmonary artery to measure hemodynamic parameters such as cardiac output, pulmonary artery pressures, and pulmonary capillary wedge pressure. It's typically used in critically ill patients to guide fluid management and vasoactive medication titration in conditions like cardiogenic shock, severe heart failure, or complex surgical cases, as supported by the 2011 ACCF/AHA guideline for coronary artery bypass graft surgery 1. On the other hand, a Premature Atrial Contraction is an early heartbeat that originates in the atria rather than from the sinoatrial node, causing an irregular heart rhythm. PACs are often benign and may be asymptomatic or cause sensations of skipped beats or palpitations. They can occur in healthy individuals but may increase in frequency with caffeine, alcohol, stress, or underlying heart disease. While occasional PACs generally don't require treatment, frequent PACs might warrant further cardiac evaluation, especially if they cause significant symptoms or occur in patients with structural heart disease.

Key Considerations for Pulmonary Artery Catheter Use

• The decision to use a PAC should be based on patient disease, surgical procedure, and practice setting, as recommended by the 2009 ACCF/AHA focused update on perioperative beta blockade 1.
• Routine use of a PAC perioperatively, especially in patients at low risk of developing hemodynamic disturbances, is not recommended, according to the 2007 ACC/AHA guidelines on perioperative cardiovascular evaluation and care for noncardiac surgery 1.
• The potential risk of complications and cost associated with catheter insertion and use must be considered, as highlighted in the 2010 clinical review on the management of perioperative heart failure in cardiac surgery 1.

Implications for Patient Care

• The use of a PAC may be reasonable in patients at risk for major hemodynamic disturbances that are easily detected by a PAC, as stated in the 2009 ACCF/AHA focused update on perioperative beta blockade 1.
• However, the decision must be based on careful consideration of the potential benefits and risks, as well as the patient's individual needs and circumstances.
• Alternative monitoring methods, such as central venous pressure monitoring, may be sufficient for patients at low risk of developing hemodynamic disturbances, as suggested by the 2011 ACCF/AHA guideline for coronary artery bypass graft surgery 1.

From the Research

Definition of PAC

• PAC can refer to two different medical concepts: Pulmonary Artery Catheter and Premature Atrial Contraction.
• A Pulmonary Artery Catheter (PAC) is a diagnostic tool used to measure stroke volume, cardiac output, mixed venous oxygen saturation, and intracardiac pressures in critically ill patients 2.
• Premature Atrial Contraction (PAC) is a type of abnormal heart rhythm characterized by early electrical impulses originating in the atria, which can increase the risk of atrial fibrillation, stroke, and death 3.

Use of Pulmonary Artery Catheter

• The use of PAC has decreased in recent years due to advances in less invasive hemodynamic monitoring techniques and the publication of randomized trials that failed to show improvements in outcome with PAC use 4.
• PAC is still indicated in some patients with circulatory and/or respiratory failure, especially when associated with pulmonary hypertension or left heart dysfunction 4.
• The routine use of PAC should be abandoned due to its invasive nature and potential for serious complications, and its use should be carefully considered on a patient-by-patient basis 5.

Premature Atrial Contraction

• Frequent Premature Atrial Contractions (PACs) can be abolished through catheter ablation, which is an effective treatment for symptomatic, frequent, and drug-refractory PACs 3.
• The electrophysiological features of PACs, including coupling intervals and ectopic foci, can be characterized and used to guide catheter ablation 3.
• PACs can increase the risk of atrial fibrillation, stroke, and death, and their treatment is important to prevent these complications 3.

Complications and Risks

• The use of PAC can be associated with complications such as cardiac arrhythmias, pulmonary hemorrhage, and infarct, as well as mortality from balloon tip rupture 2.
• The misplacement of a PAC can occur, and chest radiography and transesophageal echocardiography can be used to diagnose and correct this complication 6.
• The use of PAC can also be associated with increased costs, although the quality of evidence for this is low 2.