Slow heart rate or Bradycardia: Will my heart stop?








This video is about Slow heart rate or Bradycardia: Will my heart stop?
Hi Guys…my name is Sanjay Gupta and I am a cardiologist in York. To speak with me , visit www.yorkcardiology.co.uk/yorkcardiology@gmail.com

Today I wanted to do a video (as requested by my facebook friend Leah) on slow heart rates or as we doctors refer to it…Bradycardia.
The normal range for heart rate at rest is between 60-100 beats per minute. If you heart rate is over 100 at rest then it is described as tachycardia and if it is below 60.min then it is called bradycardia.

It is not uncommon for people to measure their heart rates and find it to be low or sometimes patients have holters and get told their heart rates are down to 30-40 beats per minute and this causes a great deal of anxiety because the automatic assumption is that the heart could slow down so much that it will stop

Truthfully this almost never happens and is an unjustified concern. In this video I will be able to explain why.

1) it is important to understand the electrics of the heart. The heart is myogenic i.e the electricity is produced within the heart cells itself. All the muscles of the heart are capable of producing electricity but there is one area of the heart which can produce the electrical impulses at the highest rate and this cluster of cells is called the Sinus node or the pacemaker of the heart. The sinus node can be likened to a man with a drum…he hits the drum and waits for the echo to die down and hits the drum. There are certain external influences which will tell the drummer to speed up or to slow down…

so adrenaline for example which is generate when you are exercising or stressed or scared or even ill will
tell the drummer to beat faster
And then there is acetylcholine which is influenced by the vagus nerve when you are resting or sleeping or even digesting which will tell the drummer to slow down

So the heart rate is situational…ie the normal heart rate is different for different situations….and therefore a heart rate of 30-40 may be completely fine when you are sleeping but will be slow for someone who is on the treadmill.

Secondly if you remove the pacemaker, that doesn’t mean the heart stops beating… another cluster of cells will take over but they wont beat as fast or strong as when the natural pacemaker is.

1) What is the heart rate and why is it important?
The heart function is to pump oxygen rich round blood round the body and to be able to pump the blood round, it has to beat at least a certain minimum number of times to get the blood round. If it doesn’t beat the minimum number of times, not as much blood will get round.. and therefore our vital organs wont get as much blood and therefore they will not function as well. Although a heart rate of less than 60 is considered slow, it often has no impact on us because as the heart slows down, the heart has more time to fill with blood and therefore although it is slower it will push more blood with each beat and therefore probably the overall same amount of blood gets round. At a certain rate however, the filling of blood will not compensate for the slow heart rate and I would say that this value would probably be even less than 45/min. Now the most sensitive part of our body to a reduction in blood supply is our brain and if our brain doesn’t get as much blood as it needs, we feel dizzy and therefore one of the first signs of our heart rate being too slow is dizziness or even blackouts if the heart rate is very slow and if these happen most people go and ask for help and the slow heart rate is picked up.

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