Differential Diagnosis for a Heartbeat that is Too Slow
When the heartbeat is too slow, it is medically referred to as bradycardia. Here are the differential diagnoses categorized for better understanding:
Single Most Likely Diagnosis
- Bradycardia: This is the most straightforward diagnosis when the heart rate is slower than normal. It can be due to various reasons such as excellent physical condition, sleep, or certain medications, but it can also be a sign of an underlying heart condition.
Other Likely Diagnoses
- Hypothyroidism: An underactive thyroid gland can cause bradycardia among other symptoms like fatigue and weight gain.
- Electrolyte imbalance: Abnormal levels of potassium, magnesium, or calcium can affect heart rhythm, leading to a slow heartbeat.
- Medication side effects: Certain medications, including beta-blockers and some anti-depressants, can slow the heart rate as a side effect.
Do Not Miss Diagnoses
- Heart block: A condition where the electrical signals between the heart's chambers are partially or completely blocked, leading to a slow heartbeat. It can be life-threatening if not treated promptly.
- Myocardial infarction (heart attack): Although more commonly associated with rapid heart rates, in some cases, a heart attack can cause bradycardia, especially if the infarct involves the heart's conduction system.
- Hypothermia: A body temperature that is dangerously low can cause bradycardia, among other critical symptoms.
Rare Diagnoses
- Sick sinus syndrome: A condition where the heart's natural pacemaker (the sinus node) does not function properly, leading to irregular heart rhythms, including bradycardia.
- Cardiac sarcoidosis: A rare condition where inflammatory cells (granulomas) form in the heart, potentially disrupting its electrical system and leading to bradycardia.
- Lyme carditis: A rare complication of Lyme disease where the bacteria affect the heart, potentially causing bradycardia due to inflammation of the heart's electrical conduction system.