What does an ECG showing normal sinus rhythm, incomplete right bundle branch block (IRBBB), and minimal voltage criteria for left ventricular hypertrophy (LVH) indicate?

Understanding Your ECG Results

Your ECG shows mostly normal findings with some minor variations that are typically benign and do not require treatment or concern in most cases. 1

What Each Finding Means

Normal Sinus Rhythm

• Your heart is beating in a regular, normal pattern originating from the correct location (the sinus node)
• This is exactly what we want to see

Incomplete Right Bundle Branch Block (IRBBB)

• This represents a minor delay in the electrical conduction through the right side of your heart 2
• IRBBB is a common ECG finding, particularly in men and athletes, and usually does not need further evaluation 2
• It can be a completely normal variant in healthy individuals 2
• The pattern shows an RSR' configuration with a QRS width below 100 milliseconds, which defines what's called the "crista supraventricularis pattern"—a benign finding representing late activation of a normal right ventricular structure 2

Minimal Voltage Criteria for Left Ventricular Hypertrophy (LVH)

• The voltage measurements on your ECG are slightly elevated but only minimally meet criteria that could suggest thickening of the left heart chamber 1
• The AHA/ACC/HRS guidelines specifically caution that terms like "borderline" and "minimal" should be used carefully because ECG voltage criteria have limited accuracy 1
• In populations where true LVH is unlikely (such as people without significant hypertension or heart disease), most positive tests are actually false positives 1
• Many factors can cause increased voltage without actual heart thickening, including: 1
  • Body build and chest wall anatomy
  • Age, gender, and race
  • Athletic conditioning
  • Normal day-to-day variation in measurements

Why This is Called "Borderline"

The term "borderline ECG" means the findings are at the threshold of normal and don't clearly indicate disease 1. The AHA/ACC/HRS guidelines recommend using qualifying terms like "borderline" with caution because they can be interpreted multiple ways and often reflect technical measurement issues rather than true abnormalities 1.

What You Should Do

In most cases, these findings require no action unless you have symptoms (chest pain, shortness of breath, palpitations) or risk factors for heart disease (high blood pressure, family history) 2. If you have concerning symptoms or risk factors, your doctor may recommend:

• Blood pressure monitoring (if you have hypertension, as this is when voltage criteria become more meaningful) 1
• An echocardiogram to directly visualize your heart if there's clinical concern 1
• Routine follow-up without additional testing if you're asymptomatic and have no risk factors 2

Important Caveats

• IRBBB can occasionally be associated with structural heart conditions, so if you have a family history of heart disease, symptoms, or if a heart murmur is detected on physical exam, further evaluation with echocardiography should be considered 2
• The presence of IRBBB can affect the accuracy of LVH voltage criteria, making the "minimal voltage criteria for LVH" finding even less reliable 1
• These ECG patterns can vary from day to day and even with electrode placement, which is why a single borderline reading often doesn't warrant concern 1