Angina pectoris is a phrase that comes from Latin and translates as 'tight chest'.
People with angina experience pain in the centre of the chest. The chest can feel constricted and tight, but the pain can also be oppressive, as if something is crushing your chest.
Pain starts in the centre of the chest behind the breast bone (sternum) or on the left side of the front of the chest. It can spread out to other parts of your body like your arms and stomach.
Angina is often brought on by:
- Physical exercise
- Extreme cold
- A heavy meal.
Once these trigger factors stop, the pain tends to fade away quickly, usually within 10 minutes.
What causes angina?
In most cases, the cause of angina is coronary atherosclerosis: the thickening of arteries that supply blood, oxygen and nutrients to the heart. This happens when fatty deposits, called plaques or atheroma, narrow the arteries over time and reduce blood flow to the heart. Symptoms may only appear at times when your heart needs more blood supply, such as when you're stressed, exercising or climbing stairs. As your heart tries to pump faster to meet your body's increased demands, the narrowed arteries struggle to keep up. The heart then receives too little oxygen, which causes pain in the heart that is felt as chest pain. In severe cases this can also happen when the heart is at rest.
Angina can be aggravated by other illnesses, including:
- A sustained fast heartbeat
- Anaemia (thin blood)
- Heart valve diseases such as severe aortic stenosis - a narrowing of the outflow valve of the heart
- Thickening of the heart muscle (hypertrophy), which can be a result of high blood pressure over several years. In rare cases, a severe spasm of a coronary artery can happen when there is relatively little narrowing from fatty deposits. The artery appears to be working normally, but is not. This is known as variant or Prinzmetal angina.
Types of angina
Stable angina: chest pain is brought on when the heart has to work harder.
Unstable angina: : there is no pattern to chest pain and it can happen when the heart is resting. Symptoms are more severe than stable angina and pain tends to last longer.
Variant angina: chest pain is caused by sudden artery spasm. This means pain can happen when the heart is at rest, more often in the early morning.
What are the symptoms of angina?
Symptoms typically start during physical exertion or emotional stress. They are often worse in cold or windy weather and sometimes after big meals.
- A squeezing or heavy pressing sensation on the chest.
- Increased shortness of breath on exercise.
- A sense of heaviness or numbness in the arm, shoulder, elbow or hand, usually on the left side.
- A constricting sensation in the throat.
- The discomfort can radiate into both arms, the jaw, teeth, ears, stomach and in rare cases between the shoulder blades.
Blood then clots around the rupture, and the clot may be large enough to block the artery and seal off the blood supply. This may cause unstable angina or a heart attack.
What are the treatment options for angina patients?
Treatment options include:
- medications (nitroglycerin, beta blockers, calcium channel blockers),
- percutaneous transluminal coronary angioplasty (PTCA), or
- Coronary artery bypass graft surgery (CABG
Resting, nitroglycerin tablets (placed under the tongue), and nitroglycerin sprays all relieve angina by reducing the heart muscle's demand for oxygen. Nitroglycerin also relieves spasm of the coronary arteries and can redistribute coronary artery blood flow to areas that need it most. Short-acting nitroglycerin can be repeated at five minute intervals. When 3 doses of nitroglycerin fail to relieve the angina, further medical attention is recommended. Short-acting nitroglycerin can also be used prior to exertion to prevent angina.
Longer-acting nitroglycerin preparations, such as Isordil tablets, Nitro-Dur transdermal systems (patch form), and Nitrol ointment are useful in preventing and reducing the frequency and intensity of episodes in patients with chronic angina. The use of nitroglycerin preparations may cause headaches and lightheadedness due to an excess lowering of blood pressure.
Beta blockers relieve angina by inhibiting the effect of adrenaline on the heart. Inhibiting adrenaline decreases the heart rate, lowers the blood pressure, and reduces the pumping force of the heart muscle, all of which reduce the heart muscle's demand for oxygen. Examples of beta blockers include:
- acebutolol (Sectral)
- atenolol (Tenormin)
- metoprolol (Lopressor, Lopressor LA, Toprol XL)
- bisoprolol (Zebeta)
- nadolol (Corgard)
- propranolol (Inderal)
- timolol (Blocadren)
Side effects include of beta blockers include:
- worsening of asthma,
- excess lowering of the heart rate and blood pressure,
- increased cholesterol levels, and
- Shortness of breath due to diminished heart muscle function (congestive heart failure).
Calcium Channel Blockers
Calcium channel blockers relieve angina by lowering blood pressure, and reducing the pumping force of the heart muscle, thereby reducing muscle oxygen demand. Calcium channel blockers also relieve coronary artery spasm. Examples of calcium channel blockers include:
- amlodipine (Norvasc)
- bepridil (Vascor)
- diltiazem (Cardizem)
- elodipine (Plendil)
- isradipine (Dynacirc)
- nicardipine, (Cardene)
- nifedipine (Adalat, Procardia)
- nimodipine (Nimotop)
- nisoldipine (Sular))
- verapamil (Calan)
Side effects of calcium channel blockers include:
- swelling of the legs,
- excess lowering of the heart rate and blood pressure, and
- Depressing heart muscle function.
Other anti-anginal drugs
Ranolazine (Ranexa) is indicated for the treatment of chronic angina. Ranexa may be used with beta-blockers, nitrates, calcium channel blockers, antiplatelet therapy, lipid-lowering therapy, ACE inhibitors, and angiotensin receptor blockers.