Bradycardia is a heart rate that’s too slow. it's totally depend on age and physical condition. Elderly people, for example, are more prone to bradycardia.

In general, for adults, a resting heart rate of fewer than 60 beats per minute (BPM) qualifies as bradycardia.

But there are exceptions. the heart rate may fall below 60 BPM during deep sleep. And physically active adults (and athletes) often have a resting heart rate slower than 60 BPM.

Causes

Causes for bradycardia include:

• Problems with the sinoatrial (SA) node, sometimes called the heart’s natural pacemaker
• Problems in the conduction pathways of the heart that don’t allow electrical impulses to pass properly from the atria to the ventricles
• Metabolic problems such as hypothyroidism (low thyroid hormone)
• Damage to the heart from heart disease or heart attack
• Certain heart medications that can cause bradycardia as a side effect

Symptoms

A heart rate that’s too slow can cause insufficient blood flow to the brain. Symptoms of bradycardia include:

• Fatigue or feeling weak
• Dizziness or lightheadedness
• Confusion
• Fainting (or near-fainting) spells
• Shortness of breath
• Difficulty when exercising
• Cardiac arrest (in extreme cases)

Complications 

Left untreated, severe or prolonged bradycardia can cause:

• Heart failure
• Fainting (syncope)
• Chest pain (angina pectoris)
• Low blood pressure (hypotension)
• High blood pressure (hypertension)

HOMOEOPATHIC TREATMENT

Cannabis indica — This remedy produces a very slow pulse, but the mental and nervous symptoms are present when it is indicated.

Ascelpias cornuti — The pulse is very slow and the patient is subject to violent nervous headaches, the pain being most marked between the eyes.  The headache is often produced by the suppression of a perspiration. There is violent vomiting with soft, yellow, bilious stools.

Digitalis— When this remedy is indicated there is usually some form of organic heart disease.  The pulse is slow but may become irregular, or intermittent, and excited by the least movement.  There is a sensation as if the heart would stop beating if he moved.

Opium — The pulse is slow and full with depression on the cerebral function, as indicated by the drowsiness and stupor, the respirations are slow, stertorous and puffing.

Paris quadrifolia — This remedy produces a slow but full pulse, especially when due to spinal affections as the result of traumatism. Thinking aggravates the pain in the occiput. The eyes feel large as if the eyelids would not close over them, or as if a thread drew them back into the head.