A “dropped QRS” on an EKG indicates a “heart block,” specifically a second-degree atrioventricular (AV) block, meaning that some electrical impulses from the atria are not being conducted to the ventricles, resulting in a missing QRS complex (a dropped beat) on the ECG tracing; this can occur in a predictable pattern depending on the type of heart block present (like Mobitz type 1 or 2). 

Key points about dropped QRS and heart block:

• Second-degree AV block:This is the most common type of heart block associated with dropped QRS complexes, where some atrial impulses fail to reach the ventricles, causing intermittent missing QRS waves.Â
• Mobitz Type 1 (Wenckebach):In this type, the PR interval gradually lengthens before a dropped beat, creating a pattern of progressively longer intervals until a QRS is missed.Â
• Mobitz Type 2:This type has a consistent PR interval with sudden dropped beats, often occurring in a predictable pattern like every 3rd or 4th P wave.Â

Important considerations:

• Severity:While a few dropped beats may not be concerning, frequent or consistent dropped QRS complexes could indicate a serious heart conduction problem requiring medical attention.Â
• Clinical symptoms:Depending on the severity of the heart block, symptoms like dizziness, lightheadedness, or fainting may occur.Â