Which of following best explains the patient’s presentation?
Anonymous Poll
28%
AV node ischemia
35%
Sick sinus syndrome
6%
Structural heart disease
31%
Electrolyte abnormalities
The ECG reveals an irregular bradycardic arrhythmia, characterized by conduction abnormalities at the level of both SA node, as evidenced by the absence of some P waves, and the AV node, where the P waves fail to conduct to the ventricles to produce QRS complexes.
The coexistence of mixed conduction abnormalities in the context of end-stage renal disease (ESRD) raises suspicion for electrolyte imbalances as the primary etiology. This hypothesis was substantiated by laboratory findings indicating elevated levels of potassium (6.7 mg/dL) and decreased levels of calcium (7.1 mg/dL).
The coexistence of mixed conduction abnormalities in the context of end-stage renal disease (ESRD) raises suspicion for electrolyte imbalances as the primary etiology. This hypothesis was substantiated by laboratory findings indicating elevated levels of potassium (6.7 mg/dL) and decreased levels of calcium (7.1 mg/dL).
What kind of block is observed in the ECG?
Anonymous Poll
16%
SA node block
26%
Type 1 AVB
24%
Second degree AV block: Mobitz type 1
24%
Second degree AV block: Mobitz type 2
10%
Complete heart block
The ECG demonstrates grouped beats. P-waves precede the QRS complexes with constant but prolonged PR intervals. This indicates a first-degree AV block.
Please note that P-wave is absent during the pause between the grouped beats. This pattern suggests an SA node block, rather than a second-degree AV block, in which a P-wave is present during the pause but is not followed by a QRS complex.
For more advanced users:
The P-P interval progressively shortens prior to the dropped P wave. The duration of the PP interval during the pause is less than twice the length of the shortest PP interval which is observed prior to the pause. This suggests a second-degree, Wenckebach sinoatrial block.
Special thanks to Dr. Salvatore for his expert ECG interpretation and the informative diagram he provided.
Please note that P-wave is absent during the pause between the grouped beats. This pattern suggests an SA node block, rather than a second-degree AV block, in which a P-wave is present during the pause but is not followed by a QRS complex.
For more advanced users:
The P-P interval progressively shortens prior to the dropped P wave. The duration of the PP interval during the pause is less than twice the length of the shortest PP interval which is observed prior to the pause. This suggests a second-degree, Wenckebach sinoatrial block.
Special thanks to Dr. Salvatore for his expert ECG interpretation and the informative diagram he provided.