Third-degree AV block comes from a complete absence of connection between the P waves and the QRS complexes. The ventricular rhythm you’ll see is a junctional or AV nodal escape rhythm. The rate is very slow and the symptoms are more significant than is seen with other AV blocks. The only effective treatment for this is to provide pacemaker therapy. Atropine will help but will be a short-term solution to the problem.
ANGINA PECTORIS The patient with angina pectoris generally has a predictable pattern of chest pressure or discomfort that comes on with exercise and is relieved by stress. It is often due to reversible or transient myocardial ischemia without true myocardial infarction. Stress can also bring this on. The actual problem is one of myocardial oxygen demand exceeding the blood supply from the coronary arteries. The cardiac workload is made worse by aortic stenosis, hypertension, hypertrophic cardiomyopathy, and aortic regurgitation. If there is anemia or high altitude, the problem will be made worse. The atherosclerotic lesion of the coronary arteries may be fixed but the narrowing itself will not be fixed. There will be changes in the vascular tone so that in the morning, for example, when the tone is greater, the chances of angina symptoms are also greater. High levels of catecholamines are causative of vasoconstriction that also contributes to the problem. The patient with typical angina will have chest pressure of variable intensity that may radiate to the jaw, neck, shoulder, or arms. In atypical angina, the patient will have gas, bloating, or abdominal pain instead of chest pain. Most of the time, the symptoms will come on with activity and will go away with rest, which provides a clue as to the causation. Some people may have nocturnal angina if they are having vital sign changes while dreaming. Diabetics have a much higher risk of silent ischemia because of nerve damage that affects the pain experienced by the heart. The diagnosis is made through evaluation of the symptoms, the ECG showing no evidence of ongoing ischemia at rest, and stress testing, which will show ischemia with exercise. If this test is positive, a coronary angiography can be done in order to confirm the presence of narrowing of the coronary arteries.
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