Symptoms of Heart Block


symptoms of heart block

Sinoatrial nodal blocks result in sinus bradycardia (slowing down of the heart caused by the sinoatrial node). However, not many patients notice it until their heartbeat drops to 50 beats per minute and below.

The most common symptoms of sinoatrial nodal blocks are:

  • Syncope – a temporary loss of consciousness which is followed by spontaneous recovery. This happens when the demand for oxygen by the brain sharply rises while the heart is unable to provide the necessary pumping action.
  • Dizziness and lightheadedness – also appear when the demand for oxygen by the brain doesn’t meet the supply.
  • Shortness of breath and exercise intolerance – this is especially noticeable in people with third degree sinoatrial block. Due to the fact that atrioventricular node can make the heart contract at the maximum rate of 60 beats per minute and when the person is performing a physically strenuous activity, the heart cannot pump enough blood to meet the needs of the body.
  • Cyanosis – the skin of the person with sinoatrial block can become cyanotic (blue) as a result of poor oxygenation of the blood (blood that is full of oxygen is bright red, while the blood that has little oxygen is dark red with a bluish tint). This is especially noticeable on the extremities and lips.
  • Peripheral edema – poor pumping action of the heart can result in accumulation of liquid in the lower extremities of the person. This can lead to a symptom known as nocturia, when the person has to urinate many times per night as the fluids that have accumulated in the legs leave the body.
  • Pulmonary vascular congestion – poor pumping action of the heart results in an increased blood pleasure within in the vasculature of the lungs. This may result in shortness of breath, dizziness, and fainting.

Case history of the patient can often include:

  • Previous cardiac history
  • Use of medications
  • Toxic exposures
  • Serious prior illness


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