Abnormal ECG

How ECG findings get categorized

A useful framework for thinking about an abnormal ECG:

Benign normal variants

Common findings in healthy people that are not clinically meaningful:

• Early repolarization — frequent in young and athletic patients.
• Incomplete right bundle branch block — often a normal variant.
• Sinus arrhythmia — heart rate varies slightly with breathing; normal.
• Athletic heart changes — sinus bradycardia, higher voltages, T-wave variations are common in trained endurance athletes.
• Non-specific ST-T wave changes — extremely common, often non-diagnostic.

Findings that usually warrant some workup

• Q waves suggesting a prior silent myocardial infarction.
• Left ventricular hypertrophy by voltage criteria — usually triggers an echocardiogram to confirm and assess BP control.
• Right ventricular hypertrophy — looks for pulmonary or congenital causes.
• Bundle branch blocks (LBBB, RBBB) — context matters; LBBB more often indicates structural disease.
• Atrial enlargement criteria — usually echo follow-up.
• QT prolongation — needs careful evaluation and a review of medications that prolong QT.

Findings that need prompt workup

• New AFib or other significant arrhythmia.
• Wolff-Parkinson-White pattern (delta wave, short PR interval).
• Brugada pattern — specific ST elevation in V1-V3, particularly with family history of sudden death.
• Long QT syndrome patterns with risk factors.
• ST elevation — must be evaluated to rule out acute coronary syndrome.
• Complete heart block or other high-degree AV block.

Why context matters more than the finding itself

The same ECG finding has different implications in different contexts:

• LBBB in a 75-year-old with hypertension — probably reflects long-standing structural changes; echo to confirm.
• LBBB in a 35-year-old with no risk factors — more likely to reflect an undiagnosed cardiomyopathy; more thorough workup including cardiac MRI sometimes.
• QT prolongation after starting a new medication — likely the medication; may not represent underlying long-QT syndrome.
• QT prolongation in a young person with a family history of sudden death — needs genetic and electro- physiology evaluation.

Your cardiologist's job is to put the ECG finding in the context of your specific clinical picture, then decide whether to leave it alone, order workup, or initiate monitoring.

The cardiology workflow for an abnormal ECG

1. First visit by video. Review the actual ECG tracing (uploaded as PDF or image), take a detailed history, assess symptoms and risk factors, decide whether additional workup is warranted.
2. Additional testing if needed. Most often an echocardiogram; sometimes a Holter or patch monitor; occasionally a stress test or cardiac MRI. All ordered to facilities near you.
3. Follow-up visit to review results and provide a definitive answer. Either reassurance, ongoing monitoring schedule, or initiation of treatment as indicated.

The bottom line

An abnormal ECG flag is a common reason to see a cardiologist, and most of the time the news is good — the finding is benign or modest. But "most of the time" is not "always," and the handful of cases where the finding is meaningful deserve to be identified. A virtual cardiology consultation is an efficient way to get the right interpretation without months of waiting.