SA_BLOCK_2
Technical documentation
Second-Degree Sinoatrial Block
Intermittent failure of impulse conduction from the SA node into atrial myocardium. In Mobitz type I, the PP interval progressively shortens until a P-QRS cycle drops. In Mobitz type II, a complete P-QRS cycle drops without prior PP variation: the pause equals an exact multiple (typically 2x) of the baseline sinus cycle.
Also known as: Second-Degree Sinoatrial Block · bloqueo sinoauricular · bloqueo SA de segundo grado · bloqueo sinoatrial · bloqueo sinoauricular de 2.º grado · second-degree sinoatrial block · BSA · SA block
What parameters does the model use?
The following values are applied by the simulation engine to this entity. They govern activation kinematics in the 3D model and the real-time synthesis of the 12-lead electrocardiogram.
What parameters does the model use?
| Parameter | Model value |
|---|---|
| Mechanism | Bloqueo |
| Impulse origin | Sinoatrial node (SA node) |
| Modeled rate | 45–75 bpm (default 60) |
| Regularity | Regularly irregular |
| P wave | Sinus (upright in I, II, aVF) |
| PR interval | 120–200 ms (default 160) |
| QRS duration | 90 ms |
| QRS morphology | Normal (narrow) |
| AV conduction | 1:1 AV conduction |
| Severity | Clinically significant |
Which leads should be evaluated?
The catalog marks as primary diagnostic leads II. Sinus pause that is an exact multiple of the PP cycle on lead II.
In the simulator, these leads are highlighted on the 12-channel tracing and corresponding vectors are rendered on the 3D model, displaying electrical changes and anatomical origin simultaneously.
Frequently asked clinical questions
How is Second-Degree Sinoatrial Block identified on the 12-lead ECG?
Intermittent failure of impulse conduction from the SA node into atrial myocardium. In Mobitz type I, the PP interval progressively shortens until a P-QRS cycle drops. In Mobitz type II, a complete P-QRS cycle drops without prior PP variation: the pause equals an exact multiple (typically 2x) of the baseline sinus cycle. The characteristic diagnostic waveforms are generated in real time across the simulated 12-lead tracing.
Which leads are critical for diagnostic confirmation?
The primary diagnostic leads are II. Sinus pause that is an exact multiple of the PP cycle on lead II. In the simulator, these channels highlight the correlation with anatomical vectors.
What is the underlying electrophysiological or anatomical mechanism?
It originates from altered conduction in the SA_NODE, mediated by bloqueo.
How can this condition be explored in the 3D simulator?
MioAtlas offers direct deep-link reproducibility with preconfigured parameters, allowing full 3D cardiac rotation and lead vector inspection.
How do you open this configuration?
The simulator encodes its full state in the query string, providing a stable and reproducible URL:
https://mioatlas.com/simulador/en/?mode=conduction&arr=SA_BLOCK_2
Related entities
Other entities in the same category within the catalog:
Sources and bibliographic references
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Anderson RH, Yanni J, Boyett MR, Chandler NJ, Dobrzynski H (2009). "The anatomy of the cardiac conduction system". Clin Anat.
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Kligfield P, Gettes LS, Bailey JJ, et al. (2007). "Recommendations for the standardization and interpretation of the electrocardiogram: Part I: The electrocardiogram and its technology". Circulation.
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Rautaharju PM, Surawicz B, Gettes LS, et al. (2009). "AHA/ACCF/HRS recommendations for the standardization and interpretation of the electrocardiogram: Part IV: The ST segment, T and U waves, and the QT interval". Circulation.