At the Heart of the Mat­ter

The Star (St. Lucia) - - HEALTH -

The heart is part of the car­dio­vas­cu­lar sys­tem and the cen­tre of our ex­is­tence. Some say it is our soul that makes and de­fines us but it is the heart that keeps us mov­ing, breath­ing and be­ing. Ac­cord­ing to the World Health Or­ga­ni­za­tion, car­dio­vas­cu­lar dis­ease is the num­ber one cause of death glob­ally with 85% of those deaths be­ing due to heart at­tack and stroke. But how many of us heed the warn­ing?

Did you know the heart is ac­tu­ally the body’s hard­est work­ing mus­cle? The heart is con­tin­u­ally work­ing whether we are at rest, ac­tive or asleep. For us to func­tion at any level our body not only needs to be fur­nished with nu­tri­ents and oxy­gen but also re­quires a sys­tem that re­moves waste and car­bon diox­ide. The blood is re­spon­si­ble for this process, but it is the heart that makes it pos­si­ble.

Lo­cated near the cen­tre of the chest, the heart is made up of four cham­bers that pump and cir­cu­late blood, oxy­gen and car­bon diox­ide around the body. Each of the cham­bers has its own func­tion and spe­cial cells for reg­u­lat­ing the heart­beat; fail­ure of any part of the sys­tem can lead to dis­rup­tion of func­tion and some­times death. The four cham­bers are sep­a­rated into left and right by a strong wall of mus­cle with valves sep­a­rat­ing the up­per and lower cham­bers, known as the atrium and ven­tri­cles re­spec­tively. The right atrium re­ceives de­oxy­genated blood from the body which then passes to the right ven­tri­cle on its jour­ney to the lungs where car­bon diox­ide is ex­pelled, and oxy­gen taken up. This oxy­genated blood then re­turns to the heart via the left atrium, where it then passes into the left ven­tri­cle to be pumped around the body via the aorta. As with all mus­cles of the body, the heart also needs oxy­gen to func­tion and it re­ceives its sup­ply of oxy­genated blood via branches from the coro­nary ar­ter­ies.

Blood is able to cir­cu­late around the body be­cause of elec­tri­cal pace­maker cells within the heart which cause a strong con­trac­tion, forc­ing blood into and out of the heart. The heart beats in two phases: sys­tole (con­trac­tion) and di­as­tole (re­lax­ation), com­prised of four stages:

• Atrial sys­tole – This lasts about 0.1 sec­onds and both atrium (up­per cham­bers) con­tract push­ing blood into the ven­tri­cles (lower cham­bers). The flow of blood is con­trolled by valves which pre­vent the blood from flow­ing back into the atrium.

• Ven­tral sys­tole – This lasts a lit­tle longer, about 0.3 sec­onds, and both ven­tri­cles con­tract, forc­ing de­oxy­genated blood back to the lungs and oxy­genated blood around the body.

• Atrial di­as­tole – Re­lax­ation of the atrium lasts for about 0.7 sec­onds. Dur­ing this time both of the atrium fill with blood.

• Ven­tral di­as­tole – The valves be­tween the up­per and lower cham­bers are forced open by the pres­sure of the blood in the up­per cham­bers. This al­lows blood to flow pas­sively into the lower cham­bers. This phase oc­curs just be­fore atrial sys­tole

It is this ac­tiv­ity we see on an elec­tro­car­dio­gram (ECG) rep­re­sented by waves, and which doc­tors re­fer to as the PQRST com­plex. When this pat­tern is dis­rupted and all cells try to lead the cy­cle, it can re­sult in an ir­reg­u­lar heart­beat or atrial fib­ril­la­tion. On av­er­age a healthy adult heart beats 60-80 beats per minute but in well-trained ath­letes the heart is more ef­fi­cient and can beat as low as 40 beats per minute.

You can mon­i­tor your heart rate by feel­ing your pulse. Pulses can be felt at the wrist, in the neck and in the foot, where the ar­ter­ies pass close to the sur­face of the skin.

When the heart is work­ing ef­fi­ciently, we do not nor­mally pay at­ten­tion to it, un­less we un­dergo stren­u­ous ac­tiv­ity and feel it beat­ing faster and harder than nor­mal to cope with the in­creased de­mand of oxy­gen that we need to gen­er­ate more en­ergy and fuel for our mus­cles to func­tion. But when things go wrong it is hard to ig­nore. Quite of­ten peo­ple do not know they have a prob­lem and the first sign is when some­thing se­ri­ous hap­pens. Mea­sur­ing our blood pres­sure (the sys­tolic – con­trac­tion and di­as­tolic – re­lax­ation phases of the heart cy­cle) is one way of de­tect­ing early signs of prob­lem with our heart. Nor­mal blood pres­sure is 120/80mmHg; it may be lower in ath­letes or ado­les­cents, but higher val­ues in­di­cate a greater risk of de­vel­op­ing se­ri­ous heart com­pli­ca­tions or suf­fer­ing a stroke.

Next week we will talk about what hap­pens when the heart goes wrong and steps you can take to get back on your feet. Also how you can change your life­style to pro­tect your heart.

Kim Jack­son is a UK-trained phys­io­ther­a­pist with over 20 years’ ex­pe­ri­ence. She spe­cialises in mus­cu­loskele­tal pain and dys­func­tion in­clud­ing back pain and sci­at­ica, stroke and other neuro con­di­tions plus sports phys­io­ther­apy, hav­ing worked with lo­cal, re­gional and in­ter­na­tional ath­letes and teams treat­ing in­juries and analysing biome­chan­ics to im­prove func­tion and per­for­mance. She is reg­is­tered with the Al­lied Health Coun­cil and is a mem­ber of PASL. She cur­rently works at Bay­side Ther­apy Ser­vices in Rod­ney Bay, O: 458 4409 or C: 284 5443; www.bayside­ther­a­py­ser­

A happy, healthy heart is the cen­tre of our ex­is­tence but we only ap­pre­ci­ate its value when some­thing goes wrong.

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