Treatment
Medical treatment
Drugs, or medication, form our most powerful ally in the management of risk factors or treatment of heart disease.
Overview
Medical therapy is the term used in medicine to describe the prescription of drugs to manage a specific diagnosis or set of risk factors. The market is constantly changing with new developments driven by a multi-billion pound pharmaceutical industry.
Do I need medical therapy?
In deciding what course of treatment to take the cardiologist will need to perform a thorough investigation of your presenting condition and it will be necessary to consider the following:
- The nature and the severity of your symptoms/condition
- Other underlying disease or co-morbidity
- Age
- Family history
- Overall health.
It is likely the cardiologist will undertake various testing most commonly ECG, Echocardiogram, Holter monitoring and frequently a functional exercise test.
What drugs are available and what do they do?
| Risk lowering therapies | Anti Anginals | Blood Pressure Treatment | Heart Failure Treatment | Rhythm management |
| Asprin | Beta Blockers | ACEI/ARB | Diuretics | BetaBlockers |
| Clopidogrel | Calcium Channel Blockers | Calcium Channel Blocker | Digoxin | Digoxin |
| Prasugrel | Nitrates | Diuretics | BetaBlockers | Class I, III, IV drugs |
| Ticagrelor | Nicorandil | BetaBlockers | ACEI/ARB | Anti-coagulants |
| Fibrates | Ivabradine | Aldosterone Blockers | Aldosterone Blockers | Amiodarone |
| ACEI/ARB | Ranolazine | Alpha Blockers | ||
| Statins | Central Drugs |
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ACE Inhibitors
Ordinarily, the level of salt, and therefore free water in the body is controlled very carefully by the kidneys filtration system. This, in turn, is under the governance of the renin, angiotensin, aldosterone axis. In heart failure, there is an abnormal set point of this axis, so the body attempts vigorously to retain fluid and sodium to maintain the forward cardiac output. This can go too far and have deleterious effects. The most sensitive part of this feedback system is the relationship of the angiotensin converting enzyme (ACE), which converts angiotensin I, to angiotensin II under the control of renin. The ACE inhibitors very strongly inhibit this pathway and have been proven in many large clinical trials, to be beneficial in all types of heart failure from mild to severe, both in terms of the patients symptoms and moreover, in terms of the patient’s longevity.
Indications:
Heart failure
Hypertension
Vascular risk reduction
Renal protection in Diabetes Mellitus
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Aldosterone Antagonists
Drugs such as spironolactone and Epleronone are weak diuretics, but can be powerful agents still. They are used in:
Heart Failure – there is evidence that they make you live longer
Hypertension -these drugs are used as the third or fourth agent if other drugs are not working
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Alpha Blockers
Doxazosin is used as an anti-hypertension agent. It blocks alpha receptors, reducing the action of body chemicals such as adrenalin and noradrenalin, and so lowering blood pressure. They also help prostate problems.
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Angiotensin Receptor Blockers (ARBs)
The downstream target of angiotensin II is the angiotensin receptor (ATII receptor). There are a number of sub-groups of this receptor, but they are located primarily on the heart muscle (myocardium) and the lining of the main arteries and blood vessels (vascular endothelium). Over activation of this occurs, in settings such as high blood pressure or heart failure. A certain group of drugs, called the angiotensin receptor blockers (ARBs) are very specific and bind this receptor to effectively switch off its down stream effects, such as thickening of the heart muscle (hypertrophy) and thickening of the arteriolar walls in hypertension. This family of drugs include agents such as Candasartan and Telmisartan, along with older agents with shorter half lives, such as Losartan.
Indications:
Hypertension
Heart Failure
Vascular Risk Reduction
Renal Protection in Diabetes Mellitus
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Anti-arrhythmic drugs
These drugs are used to treat rhythm disturbances. However, they often have side effects, and so need to be carefully monitored. They can interact with other drugs, and even food and drink, such as grapefruit juice. So, be careful to tell the doctor all about what you are taking if he decides to initiate them.
Types of drug:
Class I: Quinidine, Mexilitine, Flecanide
Class II: Beta-Blockers
Class III: Amiodarone, Sotalol
Class IV: Calcium Channel Blockers, eg Diltiazem
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Asprin
Aspirin is on the of the oldest used compounds in the doctors bag. Its uses include:
Painkiller: 300mg tablets
Vascular disease: 75-300mg tablet
It is a platelet inhibitor. The platelets are a key component in the blood coagulation chain and are responsible, in a large part, for the clots in heart attacks. Blocking this, via Aspirin, has been proven to be beneficial in a large number of clinical scenarios, most notably, in patients who have had myocardial infarction (heart attack), unstable angina, chronic stable angina; they have all been proven to be beneficial.
Atrial Fibrilliation:
The benefit of Aspirin in atrial fibrillation is less than that of Warfarin. It is now not recommended.
The downside of the regular use of Aspirin is that a certain proportion of patients are unable to take Aspirin due to gastric intolerance and the formation either of a gastritis, or more significantly, of gastric ulcers and bleeding of the stomach lining. We will evaluate your risk of developing this carefully before initiating Aspirin and may well prescribe another drug to protect the lining of the stomach during the duration of your Aspirin therapy.
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Beta Blockers
The rate of the heart and the force of its contraction are governed by careful balance of the autonomic nervous systems in the human body. The sympathetic nervous system is active in stressful situations or situations where the individual is physically active. Stimulation of this pathway causes an increase in heart rate and an increase in the force of the heart beat. This is balanced in nature by the para-sympathetic nervous system which, via the vagal nerve, slows down the heart rate and modulates the heart beat force. In patients who have angina and heart failure, the over activity of the sympathetic nervous system, is bad news.
What are Beta blockers?
The original prototype beta blocker, such as Propranolol, had excellent effects on the heart rate, but unfortunately, were associated with significant extra cardiac side effects, such as tiredness and in the case of some of the other Beta blockers, significant problems. More modern Beta blockers such as Bisoprolol are very selective for the heart and some are even more clever, having additional nitrate groups added to them, or some alpha blocking properties, such as Nebivolol and Carvidolol respectively & help dilate the blood vessels.
Why might a patient need Beta blockers?
Stable angina: the treatment of angina would involve a combination of revascularisation using coronary angioplasty or bypass surgery, but also the treatment of symptoms with tablets, such as Beta blockers. Beta stimulation primarily causes the heart rate to increase during exercise and stress. Accordingly, Beta blockade decreases or blunts the hearts need for oxygen during these situations.
Hypertension: these drugs are no longer first line agents, but if you are on them and have no problem, there is no need to change therapy
Heart failure: It is established in the treatment of chronic heart failure, that the addition of low dose Beta blockers, carefully titrating up the dose, not only improves patient’s symptomatic status, but moreover has a significant impact in their longevity.
Why is this the case?
In heart failure, it is not simply a case of their being abnormal pump function of the heart. It is a whole body disorder where there is a combination of physical pump dysfunction, abnormalities of the muscle blood flow, abnormalities of the vascular performance and abnormal activation of the neuro-humoral and endocrine systems with high levels of circulating hormones adrenaline, catecholamines and abnormalities of the renin angiotensin and aldosterone systems. Large clinical trials have shown that this therapy saves lives. The effects of Beta blockers in diastolic heart failure are less well defined, but do appear to be beneficial, and larger scale trials are currently underway to underline this.
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Calcium Channel Blockers
The intrinsic rhythm of the heart is governed by a number of so called “ion channels”. These channels allow ions, such as sodium, calcium, potassium and chloride to move in and out of the heart cell. Calcium in the cell is essential for contraction of the muscle. A certain group of drugs called calcium channel blockers (CCBs) decrease not only this rapid influx of calcium in the heart cells, but also in the smooth muscle cells, which ring the arteries and arterioles of the body.
Types of CCBs
Broadly speaking, there are two main types of calcium channel blockers.
Dihydropyridine (such as Nifedipine & Amlodipine)
Non Dihydropyridine (such as Diltiazem and Verapamil)
Who might need CCBs
Angina: there may well be patients who are unable to tolerate Beta blockers due to side effects, such as exacerbation of lung disease or asthma, tiredness or coldness with the peripheries. In these individuals, the cardiologist may often choose to use a rate limiting calcium channel blocker, such as Verapamil, to slow down the heart rate and have a similar effect to Beta blockade. Frequently, the cardiologist will use a combination of Beta blockade and Calcium channel blockers in the treatment of Angina.
Hypertension: they are excellent drugs for use in certain individuals.
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Clopidogrel (Plavix)
Clopidogrel, also known as Plavix is one of the newer thienopyridine compounds, which is a very potent platelet inhibitor.
Indications:
Vascular disease
Prevention of more strokes if you have had one
A substitute for aspirin if you are aspirin intolerant
Stents
In patients who are very high risk for coronary events, or those following intervention with drug eluting stents, the cardiologist will always use a combination of Aspirin and Plavix, unless there is good reason not so to do.
Again, as with Aspirin, there is a small degree of risk of bleeding from the lining of the stomach or other areas of the body, but your cardiologist will discuss these risks and the benefit of the treatment with you in detail during the consultation.
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Dabigatran
This is a new anti-coagulant that has been shown to be as effective at stroke prevention in Atrial Fibrillation (AF) as Warfarin, but at reduced bleeding risk, and with no need for regular blood tests. It is a new agent, and in some patients, will not be tolerated. It still carries the risk of increased bleeding, compared to taking nothing, of course.
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Digoxin
The original version of this drug was made from the plant Foxglove. In a pure form, Digoxin is used to slow the heart rate in Atrial Fibrillation, and in some patients with heart failure. It is used much less often today as other drugs have proved more effective. It can cause problems if you get dehydrated or take other medication.
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Diuretics
Diuretics, or water tablets such as furosemide, bumetanide or the weaker agent bendroflumethazide, are used in:
Heart Failure: these drugs clear the excess fluid from your body
Hypertension: bendroflumethazide and Indapamide appear to reduce blood pressure
Some of these drugs can cause side effects by leeching salts out of your body, making you feel week. They can impair kidney function if over used.
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Fibrates
These agents have less evidence than statins but may be useful in combination with statins or if you are intolerant of the statins. They are less powerful than statins. They can cause muscle aches. Examples are bezafibrate and fenofibrate.
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Nicorandil
Nicorandil is a unique drug in that it has two effects on the heart. It is used in angina.
The first, and most important, is that it inhibits a specific channel called the KATP channel, in the heart. This is most marked in the coronary blood vessels and less so in the peripheral vasculature. In essence, it dilates coronary blood vessels, but there is also evidence that it acts in a more specific way. It appears that the opening of the KATP channel in the mitochondria, is cardio protective.
Like nitrates, it can cause a headache when you first use it. Interestingly, if you are on the diabetes tablet Glibenclamide, Nicorandil does not work.
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Nitrates
What are Nitrates?
The balance of tone of the coronary and peripheral circulation is dependent in a large part, on the generation of Nitric oxide, by the lining of blood vessels. In certain disease conditions, such as hypertension and heart failure, along with coronary artery disease, the generation of nitric oxide is inadequate. The main role of nitric oxide is to dilate the vessels.
Who might need Nitrates?
Angina: These drugs artificially releases nitric oxide in the blood stream and dilates the blood vessels, both of the coronary and peripheral circulation, directly and indirectly decreasing the workload of the heart and improving anginal symptoms.
Heart Failure: In certain individuals, such as those who have a low circulating renin level, they may also be beneficial when given on a regular basis.
There are limited nitrate tolerances and should really only be given in one dose a day, allowing a nitrate free period so the bodies sensitivity to the nitrate, generated nitric oxide, is not diminished. This is often why your cardiologist will use an agent such as Imdur, which is a very well designed sustained release preparation. When you first use it, it may cause headaches. These pass after a few days use.
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Prasugrel
Prasugrel, is a new drug that is more powerful than Clopidogrel. It is used in in high risk cases, when clopidogrel alone may be inadequate or has been shown not to work. It has associated bleeding risk as it is a powerful agent. It is usually combined with aspirin, after stents, or you have had a heart attack.
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Ranolazine
Ranolazine is a new drug and is currently indicated for use in the treatment of chronic stable angina in individuals with persistent angina despite standard anti-anginal medications. Ranolazine is believed to have its effects via altering the trans-cellular late sodium current, which prevents cellular calcium overload. Unlike most other antianginal medications, ranolazine does not significantly alter either the heart rate or blood pressure. For this reason, it is of particular use in individuals with angina despite maximal tolerated doses of other anti-anginal medications.
When first starting it, you will need an ECG after about 48 hours, to ensure that the heart is not reacting badly to it.
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Statins
These agents lower cholesterol by reducing its production in the liver. They are well tolerated and have a large amount of evidence showing that they reduce heart attacks and stroke. If your risk of death, heart attack or stroke is more that 2% annually, you should be on a statin. We can calculate your risk and advise on which agent and what dose you need to be on. Although you can get muscle aches, these tablets are remarkably well tolerated and save lives.
Statin
Standard dose
Maximum dose
Maximum LDL reduction
Pravastatin
40 mg
40 mg
1.38 mmol/l
Simvastatin
40 mg
40 mg
2.01 mmol/l
Atorvastatin
40 mg
80 mg
2.58 mmol/l
Rosuvastatin
10 mg
40 mg
2.64 mmol/l
Table of statins and possible cholesterol reductions.
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Ticagrelor
Ticagrelor, is a new drug that is more powerful than Clopidogrel. It is used in in high risk cases, when clopidogrel alone may be inadequate or has been shown not to work. It has associated bleeding risk as it is a powerful agent. It is usually combined with aspirin, after stents, or you have had a heart attack. It is not used unless strongly indicated. Unlike Prasugrel or Aspirin, it has to be taken twice a day.
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Warfarin
Strong blood thinners such as warfarin or dagabitran are needed if your blood is prone to clotting.
Indications:
Atrial fibrillation
Pulmonary Embolism or DVT
Metal heart valves.
Warfarin requires careful monitoring that your cardiologist or your GP will be able to do. This involves regular blood tests to ensure your are getting enough drug. Too little, and it is not effective, too much and you will get bleeding problems. Do not take any over the counter or prescription medication without discussing it with your doctor- these drugs can interact with warfarin and risk your health. Do not stop warfarin without discussing it with your doctor.
Although often avoided to prevent bleeding problems, aspirin and even clopiodgrel may be prescribed along with warfarin in some circumstances.
How LCC Helps
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