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The causes of coronary symptoms The symptoms of coronary artery disease are caused by the reduction of myocardial perfusion that results from narrowing of the lumen of one or more of the coronary arteries. This narrowing is most often the result of atherosclerosis. Other much less common causes include: 1 coronary artery spasm (p. 146) (often in an already diseased segment of artery but sometimes as a result of the use of cocaine) 2 thrombosis (usually on an already diseased, or occasionally aneurismal, segment) 3 embolism (e.g. from an infected aortic valve) 4 congenital coronary abnormality
The causes of coronary symptoms The symptoms of coronary artery disease are caused by the reduction of myocardial perfusion that results from narrowing of the lumen of one or more of the coronary arteries. This narrowing is most often the result of atherosclerosis. Other much less common causes include: 1 coronary artery spasm (p. 146) (often in an already diseased segment of artery but sometimes as a result of the use of cocaine) 2 thrombosis (usually on an already diseased, or occasionally aneurismal, segment) 3 embolism (e.g. from an infected aortic valve) 4 congenital coronary abnormality HEART SPECIALIST IN YELAHANKA
CARDIOLOGIST IN SAHAKARANAGAR The causes of coronary symptoms The symptoms of coronary artery disease are caused by the reduction of myocardial perfusion that results from narrowing of the lumen of one or more of the coronary arteries. This narrowing is most often the result of atherosclerosis. Other much less common causes include: 1 coronary artery spasm (p. 146) (often in an already diseased segment of artery but sometimes as a result of the use of cocaine) 2 thrombosis (usually on an already diseased, or occasionally aneurismal, segment) 3 embolism (e.g. from an infected aortic valve) 4 congenital coronary abnormality 5 vasculitis.
CARDIOLOGIST IN YELAHANKA SECOND DEGREE AV BLICK There are two basic types of second-degree AV block: AV nodal Möbitz type I (Wenckebach) heart block, and the more distal and more sinister Möbitz type II heart block. Möbitz type I heart block is much more common. In Möbitz type I block the PR interval lengthens progressively with each cardiac cycle, until an atrial wave is not conducted. There is recovery of conduction and the next a wave is conducted with a shorter interval and the cycle begins again. The QRS complex is narrow (Fig 3.10) (unless associated with pre-existing BBB). The increment is largest between the first and second conducted P wave, and the PR interval continues to increase by less and less until a P wave is dropped. Möbitz type II heart block is almost always associated with a BBB (Fig 3.11), since its origin is intraventricular (below the AV node), and it tends to lapse suddenly into extreme bradycardia or asystole. It tends to be over-diagnosed, especially in the setting of 2:1 AV block (Fig 3.12). There is no lengthening of the PR interval before an atrial wave is not conducted. At times, atropine or exercise can demonstrate the site of the block, by increasing the block from 2:1 to a higher grade when the underlying mechanism is Möbitz II. Conversely, Wenckebach conduction may improve to 3:2 or better. For a distinction to be made between Möbitz type I and Möbitz type II, at least two consecutively conducted P waves have to be evaluated. This is impossible in 2:1 conduction (block) and can only be reported as 2:1 AV block (Fig 3.12). Yet this is very commonly reported as
THE BEST CARDIOLOGISTS IN YELAHANKA nvestigations of possible or probable stable angina Electrocardiography A standard 12-lead ECG should be obtained in all patients. This is likely to be normal in almost half of patients with subsequently proven coronary artery disease. Nevertheless, an abnormal trace lends weight to the symptoms and favours further investigation. Chest X-ray Routine radiology is not essential but may reveal important co-morbidities. It should always be performed in those with clinical evidence of hypertension, pericarditis (p. 174), heart failure or valvular disease, if only as a baseline. It is similarly indicated for patients with suspected or known pulmonary or systemic disease such as rheumatoid arthritis, COPD or alcoholism. Routine blood tests All patients with suspected angina should have the following routine investigations at presentation (NHF grade A recommendation): n fasting lipids, including total cholesterol, LDLs, HDLs and triglycerides—risk factors n fasting blood sugar—risk factor n full blood count—anaemia exacerbates angina n serum creatinine—impaired renal function is a risk factor and can be worsened by some cardiac investigations. If indicated clinically, thyroid function
THE BEST CARDIOLOGISTS IN YELAHANKA Second-degree AV block There are two basic types of second-degree AV block: AV nodal Möbitz type I heart block, and the more distal and more sinister Möbitz type II heart block. Möbitz type I heart block is much more common. In Möbitz type I block the PR interval lengthens progressively with each cardiac cycle, until an atrial wave is not conducted. There is recovery of conduction and the next a wave is conducted with a shorter interval and the cycle begins again. The QRS complex is narrow (unless associated with pre-existing BBB). The increment is largest between the first and second conducted P wave, and the PR interval continues to increase by less and less until a P wave is dropped. Möbitz type II heart block is almost always associated with a BBB , since its origin is intraventricular (below the AV node), and it tends to lapse suddenly into extreme bradycardia or asystole. It tends to be over-diagnosed, especially in the setting of 2:1 AV block . There is no lengthening of the PR interval before an atrial wave is not conducted. At times, atropine or exercise can demonstrate the site of the block, by increasing the block from 2:1 to a higher grade when the underlying mechanism is Möbitz II. Conversely, Wenckebach conduction may improve to 3:2 or better. For a distinction to be made between Möbitz type I and Möbitz type II, at least two consecutively conducted P waves have to be evaluated. This is impossible in 2:1 conduction (block) and can only be reported as 2:1 AV block (Fig 3.12). Yet this is very commonly reported as Möbitz type
BEST CARDIOLOGY HOSPITALS IN BANGALORE Cardiac failure Cardiac failure is an increasingly common condition affecting about 1% of the population but much higher proportions of older people. It is responsible for an increasing number of hospital admissions. The various aetiologies have been discussed above, but the most common cause is now ischaemic heart disease rather than hypertensive heart disease. This reflects the improved modern management of hypertension in the population. The definition of heart failure has always included reference to the inability of the heart to meet the metabolic needs of the body. The earliest concepts of heart failure were of inadequate cardiac pump function and associated salt and water retention. Treatment was aimed at improving cardiac contractility and removing salt and water from the body. In the 1970s the concept of after-load reduction was introduced. This was based partly on the realisation that vasoconstriction was part of the problem. This has led to the modern neuro-hormonal concept of heart failure. It is clear that many of the features of cardiac failure are a result of stimulation of the renin-angiotensin-aldosterone system and sympathetic stimulation. These responses of the body to the fall in cardiac output temporarily increase cardiac performance and blood pressure by increasing vascular volumes, cardiac contractility and systemic resistance. In the medium and longer term these responses are maladaptive. They increase cardiac work and left ventricular volumes and lead to myocardial fibrosis with further loss of myocytes. Most recently it has become clear that heart failure is also an inflammatory condition, with evidence of cytokine activation. Work is underway to establish a role for treatment of this part of the condition. Current drug treatment has been successful in blocking many of the maladaptive aspects of neuro-hormonal stimulation. Many of these treatments have become established after benefits have been ascertained in large randomised controlled trials. These trials have also led to the abandoning of certain drugs (often those that increase cardiac performance) that were shown to have a detrimental effect on survival (e.g. Milrinone). The principles of treatment of heart failure are as follows: 1 Remove the exacerbating factors. 2 Relieve fluid retention. 3 Improve left ventricular function and reduce cardiac work; improve prognosis. 4 Protect against the adverse effects of drug treatment. 5 Assess for further management (e.g. revascularisation, transplant). 6 Manage complications (e.g. arrhythmias). 7 Protect high-risk patients from sudden death.
CARDIOLOGIST IN YELAHANKA causes of coronary symptoms The symptoms of coronary artery disease are caused by the reduction of myocardial perfusion that results from narrowing of the lumen of one or more of the coronary arteries. This narrowing is most often the result of atherosclerosis. Other much less common causes include: 1 coronary artery spasm . (often in an already diseased segment of artery but sometimes as a result of the use of cocaine) 2 thrombosis (usually on an already diseased, or occasionally aneurismal, segment) 3 embolism (e.g. from an infected aortic valve) 4 congenital coronary abnormality 5 vasculitis.
HEART SPECIALISTS IN YELAHANKA NEW TOWN BANGALORE The causes of coronary symptoms The symptoms of coronary artery disease are caused by the reduction of myocardial perfusion that results from narrowing of the lumen of one or more of the coronary arteries. This narrowing is most often the result of atherosclerosis. Other much less common causes include: 1 coronary artery spasm (often in an already diseased segment of artery but sometimes as a result of the use of cocaine) 2 thrombosis (usually on an already diseased, or occasionally aneurismal, segment) 3 embolism (e.g. from an infected aortic valve) 4 congenital coronary abnormality 5 vasculitis. Numerous other cardiac symptoms and problems can be the eventual result of atheromatous coronary disease. These include myocardial infarction , cardiac failure cardiac arrhythmias and some cardiac valve problems. Risk factor mechanisms of action Atherosclerosis is thought to result primarily from a disturbance of the vascular endothelium. The final common pathway for the effects of endothelial dysfunction is largely through abnormalities of nitric oxide (NO) production. This chemical, released by a healthy endothelium, is a potent vasodilator and has anti-inflammatory and other favourable actions on the arteries. Causes of this disturbance can be: n mechanical (hypertension) n chemical (oxidised lipids, components of cigarette smoke, hyperinsulinaemia) or n due to immunological injury. The damaged endothelium attracts inflammatory mediators, platelets and circulating lipids and promotes fibroblast and smooth muscle proliferation. This results in the formation of a plaque, which may narrow the arterial lumen. Plaques can remain stable (or sometimes regress), enlarge, rupture or erode (more common in diabetics). Most acute ischaemic events (acute coronary syndromes or acute myocardial infarctions) are thought to be the result of further luminal narrowing caused by the formation of partly or fully occlusive thrombus on a ruptured or eroded plaque. Coronary risk factors may therefore operate because they are atherogenic or thrombogenic. Plaque rupture Plaque rupture may be at least partly an inflammatory process involving inflammatory cells, cytokines and even bacteria. This may explain the association between inflammatory markers such as high-sensitivity C reactive protein (hsCRP) and a risk of acute coronary events. Although this association seems well established, there is still uncertainty about its role in overall risk assessment Plaques at risk of rupture are called vulnerable plaques. They typically have a thin fibrous cap. The shoulde of these caps are at risk of rupturing and allowing material from within the plaque to come
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