What is the management of borderline septal Q waves?

From the Guidelines

Borderline septal Q waves typically do not require specific management as they are often a normal variant found on electrocardiograms (ECGs). These shallow Q waves in leads V1-V3 represent normal septal depolarization and should not be confused with pathological Q waves that indicate myocardial infarction, as outlined in the third universal definition of myocardial infarction 1. According to this definition, a Q wave is considered pathological if it is 0.03 sec or longer and 0.1 mV deep, or if there is a QS complex in leads I, II, aVL, aVF, or V1–V6 in any two leads of a contiguous lead grouping.

In the context of borderline septal Q waves, it is essential to consider the clinical presentation and other ECG findings. If these Q waves are new or accompanied by symptoms like chest pain, shortness of breath, or other ECG abnormalities, further cardiac evaluation is warranted, including serial ECGs, cardiac biomarkers (troponin), and possibly echocardiography or stress testing 1. The distinction between normal septal Q waves and pathological Q waves is crucial, with normal septal Q waves being typically narrow (<0.04 seconds), shallow (<25% of the R wave amplitude), and present only in the septal leads, whereas pathological Q waves are wider, deeper, and may appear in contiguous leads representing a coronary artery territory.

Some key points to consider in the management of borderline septal Q waves include:

• Clinical context is crucial in interpretation, as borderline Q waves in an asymptomatic young person are likely benign, while similar findings in an older patient with cardiovascular risk factors might require more thorough investigation.
• The presence of other ECG abnormalities, such as ST-segment elevation or depression, T-wave inversion, or QT interval prolongation, may indicate myocardial ischemia or infarction and require prompt evaluation and treatment.
• The use of additional ECG leads, such as posterior leads (V7-V9) or right precordial leads (V3R, V4R), may be helpful in diagnosing myocardial ischemia or infarction in specific clinical contexts, such as suspected circumflex occlusion or right ventricular infarction 1.

Overall, the management of borderline septal Q waves should be guided by a thorough clinical evaluation, consideration of other ECG findings, and the use of additional diagnostic tests as needed to rule out myocardial ischemia or infarction.

From the Research

Borderline Septal Q Waves Management

• The presence of Q waves in patients with ST-elevation acute coronary syndromes has been associated with adverse implications, including increased in-hospital mortality 2.
• Q waves are a major determinant of in-hospital mortality, and targeted interventions should be directed to these high-risk patients 2.
• The incidence of Q waves at presentation or during hospitalization has been found to decrease over time, from 61% to 39% between 1999 and 2006 2.
• The relationships between Q waves, clinical characteristics, and cardiovascular outcomes have been studied, with Q waves being associated with less successful reperfusion and increased cardiovascular events 3.
• Evaluating for Q waves prior to discharge is a simple method of assessing for less successful reperfusion and an increased risk of adverse 30-day cardiovascular outcomes 3.
• The combination of Q waves and 90-minute ST-segment resolution allows for additional risk refinement 3.
• The presence of Q waves on the presenting electrocardiogram in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention is an independent predictor of mortality 4.
• The association between Q waves and cardiac death is consistent regardless of sex, diabetes status, target vessel, or door-to-balloon time 4.
• Beta-blockers and ACE inhibitors are commonly used in combination to manage various cardiovascular diseases, including hypertension, arrhythmias, and heart failure 5.
• The combination of beta-blockers and ACE inhibitors has been found to provide effective blood pressure lowering and improved cardiovascular outcomes 5.
• Abnormal Q waves in right-sided chest leads can be provoked by the onset of right bundle-branch block in patients with anteroseptal infarction, leading to erroneous conclusions about the extent of the infarct 6.

Management Considerations

• Patients with Q waves should be closely monitored for signs of cardiovascular complications, such as congestive heart failure and cardiac death 2, 3, 4.
• Targeted interventions, such as primary percutaneous coronary intervention and the use of beta-blockers and ACE inhibitors, should be directed to high-risk patients with Q waves 2, 4, 5.
• Evaluating for Q waves prior to discharge can help identify patients at increased risk of adverse cardiovascular outcomes 3.
• The combination of Q waves and 90-minute ST-segment resolution can provide additional risk refinement and guide management decisions 3.