I just want to discuss the ‘sensation’ of pauses. In a lot of patients that I see, both those with pacemakers and those without, it isn’t unusual for the pause they are describing to show up on monitoring as an early beat (Ventricular Ectopic) and these pauses are normally followed by the sensation of a strong beat. An extra beat? I hear you cry, but I don’t feel it and I have taken my pulse when it happens and I don’t feel it there either!!
This article is not suggesting all pauses aren’t pauses, quite obviously some are and for that reason any pauses should be investigated by a Doctor!
Premature Venticular Ectopics (Early Beats) are often responsible for this sensation though and this is partly to do with Starlings Law which states that the stroke volume of the heart increases in response to an increase in the volume of blood filling the heart (the end diastolic volume) when all other factors remain constant. YAWN!!!!!
I’ve attempted to explain in the analogy below, in brackets are the parts of YOU that the objects represent.
I want you to imagine holding a balloon (Heart) and filling it up from a tap, you wait until it is under pressure and really full and you remove it from the tap. You let go and the balloon blasts water (blood) at high velocity all over your kitchen (Body) and you get shouted at by your other half (Stress). This is your ‘Normal’ heart beat! As you remove the balloon it is allowed to contract (beat) and because it is full and under pressure its contraction is more forceful and gets the water everywhere.
Now you take this balloon and put it back to your tap (despite being warned by your other half not to do that again!) but this time you take it back off early after only a few drops of water have had a change to fill the balloon before you remove it. What happens? a few drops trickle from the top of the balloon your hand might get wet but this time your other half isnt shouting because water has barely left the sink area. This early removal of the balloon represents an early heart beat (Ventricular Ectopic) the balloon has contracted all the same but because of the decrease in water inside it and a reduction in the amount of pressure the contraction doesn’t move as much blood under normal pressures.
In fact if you were taking your pulse when this happened you wouldn’t even feel it!!!
I took the pulse of a patient once and I thought it was 30 bpm. In fact it was actually nearer 60bpm but each 2nd beat was early (Bigeminy).
When an early beat occurs the heart often does slightly delay the beat immediately after also the heart has not expelled as much blood as it normally would. So to explain the strong beat that people feel you need to imagine the sequence of events.
You are filling your balloon up and letting it blast water all over the kitchen at regular intervals (lets pick a number from thin air 5 seconds) all of a sudden you have an early beat, you remove the balloon after 1 second and it doesn’t really shoot its water anywhere and a lot of the water remains in the balloon, you then put the balloon back on and keep it there for a fraction longer but you are adding water to the water all ready in there! this time when you come to remove the balloon it is extra full and under extra pressure. Its a good thing your other half has left the house because your balloon shoots water under even higher pressure all over the kitchen and it even hits the ceiling!!
This is the strong beat you often feel after an early beat (which you often don’t feel at all) confusing right!
If you would like a much more scientific and accurate explanation of Starlings Law you may find this link below useful! Good old Wikipedia!