nhsmanagers.net Briefing 21 January 2017 Medicine for Managers Dr Paul Lambden BSc MB BS BDS FDSRCSEng MRCS LRCP DRCOG MHSM FRSM Heart Attack How medicine has changed in forty years. I am sure many of you, who had relatives in the sixties and seventies who suffered heart attacks, will remember the strict treatment regime; seven days bed rest then seven days of mobility increasing by half an hour a day. It was ten days before you could walk to the toilet! Hospital stays were two to three weeks, What transformation in the management of heart attack. Almost every aspect has changed completely from the moment the first health professional arrives to the point when the patient is stable in hospital and beyond. A heart attack (or myocardial infarction MI) is a serious medical emergency. It occurs because one of the major vessels supplying the heart (the coronary arteries) suddenly becomes obstructed and blood flow to that part of the heart stops. The sudden reduction in blood flow to the affected area (called ischaemia) may result in damage or death (necrosis) of an area of heart muscle. The two main coronary arteries arise from the base of the aorta just after it leaves the left ventricle. The two arteries, left and right, travel across the surface of the heart as shown in the diagram. The left coronary artery supplies the left atrium and the left ventricle. It produces two main branches, the left circumflex artery and the left anterior descending artery. They divide into smaller branches which supply the left side of the heart with the richly oxygenated blood. The right coronary artery supplies the right atrium and the right ventricle together with the electrical conduction system which transmits stimuli through the heart to produce the contractions. The arteries are functionally end arteries. That means that each of the branches of each coronary artery is the only vessel which supplies a specific part of the heart muscle or other structure. Therefore if any branch is blocked then the area supplied by that branch is damaged or destroyed. The larger the branch of the coronary artery that is blocked, the larger the area of the heart that is damaged or destroyed. The death of a large part of the
heart muscle is usually incompatible with life and the patient dies. If the obstruction of the artery is very gradual so that the blood flow is only very slowly compromised, then sometimes other arteries can open up to supplement the blood flow to the area and, in the event of the first artery becoming blocked the socalled collateral circulation may minimise or prevent muscle death. The Symptoms of a Heart Attack Heart attacks are regularly played out on television and film and usually display most or all of the following symptoms: 1. Chest Pain. Felt in the centre of the chest it is Why Do Heart Attacks Occur? As explained earlier, heart attacks occur because an artery becomes blocked resulting in death of some heart muscle (myocardium). The blockage occurs because the arteries become progressively clogged with thick deposits of cholesterol which form plaques. The plaques become hardened and the resulting material is called atherosclerosis which sticks to the walls often described as constricting or feeling as if a heavy weight is on the chest. The pain may radiate up to the jaw, down to the abdomen and classically down the left arm. 2. Breathlessness. Inability to take a deep breath in. 3. Nausea and Vomiting. 4. Sweating. In addition the patient may feel dizzy or lightheaded and may be gripped by panic and fear that he or she may die (and might be right). However, not everyone experiences the severe chest pain. For some it may be relatively mild and may be mistaken for indigestion. On occasion it may produce very little in the way of symptoms such that it is discovered only on ECG often by chance. These are called silent myocardial infarcts. of the arteries narrowing the lumen of the vessel(s). The flow therefore slows so that the heart does not receive as much blood as it needs, particularly during times of exertion. This results in a reversible chest pain, also felt centrally and possibly radiating to arm and jaw but usually without the more severe vomiting, sweating and breathlesness. This is called angina pectoris (derived from the Latin words angere to strangle and pectus chest, so that the condition is described by its name, strangling the chest). Unlike the pain of a heart attack angina is reversible. When the patient stops his or her exertion, the muscle demand for blood diminishes and the sluggish flow through the narrowed vessels once again becomes adequate so that the symptom disappears. The pain actually develops during exertion because
the tissue is supplied with inadequate oxygen and lactic acid which accumulates in the muscle is not broken down to carbon dioxide and water. Lactic acid lowers the ph and causes the pain. When the blood flow is restored, the acid breakdown occurs which results in the disappearance of the pain. When a blood clot forms in the narrowed and damaged artery, the acute stoppage of blood results in the acute deprivation of oxygen and nutrients to the affected area of heart muscle and the heart attack results from muscle death. Major risk factors for angina include smoking, diabetes, a raised cholesterol, high blood pressure, lack of adequate exercise and a family history of heart disease. What to do with a suspected heart attack? In anyone with symptoms which might suggest a heart attack, there are things to do urgently Call an ambulance Establish whether the patient has had similar symptoms before, if he or she has angina and, if so, does he or she have either tablets or an anti-anginal spray to use under the tongue. If available (and if the patient is not allergic) it may help to chew and swallow a standard adult (300 mg) aspirin. Aspirin exerts a mild anticoagulant effect. Try to reassure the patient and keep him or her calm. During this acute period, the patient may suffer a cardiac arrest. This may be recognised by loss of all responsiveness, lack of movement and cessation of breathing. Immediate management is to attract the attention of others to assist and to commence cardiac compressions. These days hands-only cardio-pulmonary resuscitation is advocated and the mouthto-mouth element, which discouraged so many people, is now not required. Once it has been established that a patient is in cardiac arrest 1. Dial 999 2. Sweep the finger round the mouth to remove any loose dentures etc. 3. Place the heel of the hand over the breastbone on the centre of the chest. Place the second hand on top of the first and lock the fingers. Using the body weight compress the chest by pressing down 5-6 cm and continue to do so, at a rate of about 110-120 compressions per minute until the ambulance arrives. It helps to do this whilst singing an appropriate song to oneself. Younger people would use Stayin Alive by the BeeGees whilst those of us more stricken in years still remember Nellie the Elephant by Mandy Miller. The rhythm of either is suitable. Survival and Complications The immediate survival depends on a number of factors; the severity of the heart attack and how much of the heart is damaged (which depends on the artery that is blocked; the time it takes for resuscitation and subsequently medical assistance to arrive; and, the age of the patient. The heart attack may result in the development of an abnormal heart rhythm which may prevent the heart from circulating blood properly; part of the
heart wall may rupture or the patient may develop cardiogenic shock ( the sudden failure of the heart to be able to pump sufficient blood which is frequently rapidly fatal). Arrival at a medical facility On reaching hospital, a range of tests can be done quickly to assess the severity of any heart damage: Blood tests can confirm heart damage and the degree of damage sustained. Normally a range of tests is done to check for anaemia, electrolyte disturbances, liver and kidney function, cholesterol, etc. A particular test measures a heart protein called troponin which is released according to the damage done to the heart. Electrocardiogram Mandatory and shows the pattern of electrical activity in the heart and any defective areas. Chest X-ray Echocardiogram is an ultrasonic scan to build a picture of the heart to assess the degree of damage and how function has been affected. Types of Heart Attack The term acute coronary syndrome is used increasingly (even on TV hospital dramas). Essentially it is a term to describe the sudden reduction in blood flow to part of the heart muscle and the term includes a range of types of heart attack and a condition called unstable angina. The two principal types of heart attack are distinguished by the appearance of the electrocardiogram (ECG). They are called: STEMI NSTEMI It sounds complicated. Let s try to explain The classic appearance of an ECG is as above. The various stages in an electrical wave shown, PQRST, constitute the transfer of an electrical impulse through the heart during a single beat. The P wave represents the spread of electricity down through the atria of the heart. The QRS complex represents the continuing spread of the electrical activity through the ventricles The T wave occurs as the electrical depolarisation is reversed ready for the process to start again to trigger the next beat. The ST segment is the part of the ECG at the end of the ventricular contraction/ depolarisation and the repolarisation phase when the heart rests momentarily. Changes in the ST segment define the nature and severity of a heart attack. The part of the ECG which is the ST-segment is marked on the picture of the ECG. In some heart attacks the ST-segment is elevated. Compare the appearance of the ST-segment in the ECG below with the earlier diagram of a standard ECG. An ST Elevation Myocardial Infarct (STEMI) is the most serious type of heart ST Segment
attack because it is associated with extensive damage to the heart. A non-st Elevation Myocardial Infact (NSTEMI) is likely to be less serious than a STEMI because there is less blood supply compromise and less damage and death of heart muscle. However it is still treated seriously. Ongoing Care Once stable and settled in hospital, further investigations may be carried out. Coronary Angiography is a technique for outlining the coronary arteries to establish what condition they are in. It involves feeding a catheter, usually into the groin, up through the vascular system into the heart and then into the coronary arteries using X-ray guidance Radio-opaque dye is then pumped through the catheter to identify any areas of the artery that are narrowed or blocked. Management of the Heart Attack. Medical Management: Often less severe MIs do not need a surgical intervention. 1. Lifestyle; all the usual steps really. Stop smoking, lose weight, have a good diet, have alcohol only in moderation and take regular exercise 2. Cardiac rehabilitation. A structured programme of education about the nature of the disease, how life changes, what medication may be required, risk factors etc. 3. Management of anxiety or depression. Many people find that a heart attack causes anxiety and subsequently they may become depressed. This should be managed vigorously by the GP. Medication: These days there are a host of medicines which may be valuable for post-infarct patients. It is important to control and manage effectively any concomitant diseases such as diabetes or thyroid disorders which may increase the risk of recurrences and complications. There are then groups of drugs which have actions on the heart to help it function optimally following damage: ACE Inhibitors (angiotensin converting enzyme inhibitors) Lower blood pressure and dilate blood vessels. e.g. ramipril, enalapril, captopril, lisinopril ARBs (angiotensin receptor blocking drugs) act in a similar way to ACE inhibitors but are used when the side effects of the drugs limit their use. e.g. losartan, valsartan, candesartan Anti-platelet drugs help prevent blood clots forming in the vessels by reducing the coagulability of the platelets. Low dose aspirin may be sufficient but, particularly after some types of surgery clopidogrel may be then treatment of choice. Warfarin may be used sometimes but it needs regular monitoring and if the blood level rises too high it may cause spontaneous bleeding. It is gradually being replaced by other anticoagulants that do not require the monitoring and are safer. Beta Blockers Lower blood pressure, relax the heart muscle and slow the heart beat by blocking the effects of adrenaline and
noradrenaline. e.g. bisoprolol, nadolol, sotolol Statins lower blood cholesterol. This will reduce the risk of further coronary artery damage and therefore of another heart attack. e.g. simvastatin, atorvastatin, rosuvastatin. Other medications may be required to modify or control rhythm or rate and to reduce fluid load in order to allow the heart to work as efficiently as possible within the constraints resulting from the heart attack. Surgical Interventions Coronary angioplasty Usually carried out in regional centres, it involves passing a balloon catheter into the obstructed coronary artery. When the blockage is reached the balloon is inflated opening up the artery. Once opened a flexible metal mesh cylinder Foundation produces a fact sheet which gives stark data: TODAY IN THE UK 435 people will die of cardio-vascular disease 7 million people have cardio-vascular disease 515 people will go to hospital with a heart attack 190 people will die of a heart attack NOW FOR THE GOOD NEWS In the 1960s 7 out of 10 heart attacks were fatal Today 7 out of 10 people survive. paullambden@compuserve.com (stent) is opened in the artery to maintain its patency. Coronary artery byepass surgery Sometimes it is not possible to use an angioplasty technique to restore the circulation in the coronary arteries if they are extensively blocked, several small branches are blocked or it is anatomically difficult. The operation, known as a CABG (pronounced cabbage) involves taking a blood vessel from elsewhere in the body and grafting it to the coronary artery byepassing an area of blockage. People often have three or four arteries grafted (triple or quadruple byepass) Heart attack is still a major cause of death and complications. The British Heart