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Bradyarrhythmias are cardiac rhythm disorders characterized by a slower-than-normal heart rate, typically defined as fewer than 60 beats per minute. Some of which are discussed here:Sinus BradycardiaSinus bradycardia presents a heart rate lower than 60 beats per minute, with a regular rhythm originating from the SA node. The ECG typically shows normal P waves preceding each QRS complex, a normal PR interval (0.12 to 0.20 seconds), and a normal QRS duration (0.06 to 0.10 seconds).First-Degree AV...

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Dysrhythmias refers to abnormalities in the heart's rhythm. They result from disruptions in the heart's electrical conduction system, which includes the sinoatrial(SA)node, atrioventricular(AV) node, the bundle of His, bundle branches, and Purkinje fibers.Definition and PathophysiologyDysrhythmias result from disorders of impulse formation, impulse conduction, or both. The heart contains specialized cells in the sinoatrial node, atrioventricular node, and the bundle of His and Purkinje fibers...

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Cardiac Action Potential

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Benefits of Cardiac Resynchronization Therapy in an Asynchronous Heart Failure Model Induced by Left Bundle Branch Ablation and Rapid Pacing

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Transient Left Bundle Branch Block due to Severe Hyperkalemia.

Kishore Kumar¹, Madhavi Biyyam¹, Amandeep Singh¹

¹Department of Medicine, Bronx Lebanon Hospital Center, Bronx, NY 10457, USA.

Cardiology Research

|May 19, 2017

Summary

Severe hyperkalemia can cause dangerous heart rhythm changes. This case shows how high potassium levels mimicked a left bundle branch block on ECG, which resolved after dialysis.

Keywords:

ECG Hyperkalemia Left bundle branch block

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Area of Science:

Cardiology
Nephrology
Electrolyte Imbalance

Background:

Hyperkalemia is a critical electrolyte disturbance associated with significant cardiac risks, including arrhythmias and asystole.
End-stage renal disease (ESRD) patients are particularly vulnerable to hyperkalemia due to impaired renal potassium excretion.

Observation:

A 52-year-old male with ESRD presented with weakness and lethargy after missing hemodialysis.
Electrocardiogram (ECG) revealed sinus tachycardia, wide QRS complexes, peaked T waves, and a left bundle branch block (LBB) pattern.
Initial serum potassium was critically elevated at 8.8 mEq/L.

Findings:

Emergent hemodialysis was initiated to correct the severe hyperkalemia.
Post-hemodialysis, serum potassium normalized to 4.3 mEq/L.
Repeat ECG demonstrated complete resolution of the LBB pattern, with normalization of QRS duration.

Implications:

This case highlights that hyperkalemia can present with ECG findings mimicking LBB, a potentially reversible condition.
Prompt recognition and management of hyperkalemia are crucial in ESRD patients to prevent life-threatening cardiac events.
ECG monitoring is essential in patients with ESRD and suspected electrolyte abnormalities.