Heart block is diagnosed through a combination of clinical evaluation and diagnostic tests, primarily focusing on electrocardiography (ECG) findings.
| Pivotal Assessment | Finding |
|---|---|
History |
Symptoms: Dizziness, fatigue, syncope (fainting), palpitations, or bradycardia (slow heart rate).
Medical history: History of heart disease, medication use (e.g., beta-blockers, calcium channel blockers, digoxin), or prior cardiac procedures.
First-degree heart block: Prolonged PR interval (>200 ms) but consistent conduction of every atrial impulse to the ventricles.
Second-degree heart block:
Mobitz Type I (Wenckebach): Progressive PR prolongation until a beat is dropped.
Mobitz Type II: Sudden non-conducted P waves without prior PR prolongation.
Third-degree (Complete) Heart Block: No relationship between P waves and QRS complexes (complete AV dissociation).
Holter Monitor: Continuous 24-48 hour ECG recording for intermittent blocks.
Event Monitor: Longer-term monitoring (weeks to months) for infrequent symptoms.
Implantable Loop Recorder: For detecting rare, undiagnosed episodes of heart block.
Evaluates if the heart block worsens with exertion.
Helps assess conduction abnormalities and determine the need for pacemaker implantation.
Electrolyte levels (e.g., potassium, calcium, magnesium)
Thyroid function tests (hypothyroidism can cause bradycardia)
Cardiac MRI or Echocardiography to assess structural heart disease.
Management depends on the type and severity of the block, ranging from observation in mild cases to pacemaker implantation in symptomatic or high-grade blocks.
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