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CARDIOLOGY DOCTORS IN HOSUR ROAD Pulmonary embolism This is not quite a cardiac condition and not quite a respiratory condition but it is often managed by cardiologists. Modern CT pulmonary angiography is very sensitive and specific for the diagnosis of PE. A negative scan that is of good quality effectively excludes the diagnosis. The scans are so sensitive that small distal emboli may be detected in patients who do not have convincing symptoms of embolism. This poses a therapeutic problem that may be avoided if scans are not ordered inappropriately. Some patients cannot have a CTPA, usually because of renal impairment that would make the injection of contrast risky. A V/Q nuclear scan is then a reasonable alternative to a CTPA. These scans are less accurate than CT pulmonary angiography but the clinical suspicion of PE and a lung scan reported as intermediate or high probability is an indication for treatment. Patients should be admitted to hospital and treatment begun with intravenous heparin or subcutaneous low molecular weight heparin. The latter has the advantage that the dose is determined by body weight and repeated measurements of clotting times are not required. In some cases it may be possible to treat patients with small pulmonary emboli at home with supervised low molecular weight heparin. Either way, soon after diagnosis patients should be started on oral anticoagulation treatment with warfarin. A stable INR may often be achieved within five days or so, the heparin ceased and the patient discharged. Most patients with dyspnoea as a result of PE begin to feel better within a few days of starting treatment. It is often difficult to know how long to continue treatment with warfarin. The usual recommendation for an uncomplicated first PE is three to six months. Recurrent PE may be an indication for lifelong treatment. It also suggests a need to investigate for clotting abnormalities (e.g. anti-thrombin III deficiency, protein S and protein C deficiency, abnormal Factor V and anti-nuclear antibody). A very large and life-threatening PE which is associated with the sudden onset of severe dyspnoea and hypotension may be an indication for thrombolytic treatment. An echocardiogram may show abnormal right ventricular function in these ill patients and help in the decision. Experience with this is limited and the optimum regimen is not really known. Tissue plasminogen activator (TPA) is now indicated for this purpose and current recommendations are for a 10 mg bolus over two minutes followed by 90 mg over two hours.
THE HEARTDOCTORS IN BANGALORE Pulmonary embolism This is not quite a cardiac condition and not quite a respiratory condition but it is often managed by cardiologists. Modern CT pulmonary angiography is very sensitive and specific for the diagnosis of PE. A negative scan that is of good quality effectively excludes the diagnosis. The scans are so sensitive that small distal emboli may be detected in patients who do not have convincing symptoms of embolism. This poses a therapeutic problem that may be avoided if scans are not ordered inappropriately. Some patients cannot have a CTPA, usually because of renal impairment that would make the injection of contrast risky. A V/Q nuclear scan is then a reasonable alternative to a CTPA. These scans are less accurate than CT pulmonary angiography but the clinical suspicion of PE and a lung scan reported as intermediate or high probability is an indication for treatment. Patients should be admitted to hospital and treatment begun with intravenous heparin or subcutaneous low molecular weight heparin. The latter has the advantage that the dose is determined by body weight and repeated measurements of clotting times are not required. In some cases it may be possible to treat patients with small pulmonary emboli at home with supervised low molecular weight heparin. Either way, soon after diagnosis patients should be started on oral anticoagulation treatment with warfarin. A stable INR may often be achieved within five days or so, the heparin ceased and the patient discharged. Most patients with dyspnoea as a result of PE begin to feel better within a few days of starting treatment. It is often difficult to know how long to continue treatment with warfarin. The usual recommendation for an uncomplicated first PE is three to six months. Recurrent PE may be an indication for lifelong treatment. It also suggests a need to investigate for clotting abnormalities (e.g. anti-thrombin III deficiency, protein S and protein C deficiency, abnormal Factor V and anti-nuclear antibody). A very large and life-threatening PE which is associated with the sudden onset of severe dyspnoea and hypotension may be an indication for thrombolytic treatment. An echocardiogram may show abnormal right ventricular function in these ill patients and help in the decision. Experience with this is limited and the optimum regimen is not really known. Tissue plasminogen activator (TPA) is now indicated for this purpose and current recommendations are for a 10 mg bolus over two minutes followed by 90 mg over two hours. 7
CARDIOLOGISTS IN HEBBALA Risk stratification using myocardial perfusion scans A normal perfusion scan is associated with a good prognosis. The annual rate of myocardial infarction of cardiac death is < 1%, at least for some years. Stress echocardiography Ischaemic areas of myocardium are known to have reduced contraction compared with normal areas. This can be demonstrated by high-quality echocardiograms. A number of standard views of the heart are obtained and the wall is divided into regions that are assessed for reduced motion. The echo equipment must be designed to store rest images and to present them next to stress images on a split screen so that direct comparison can be made. The stress can be provided by exercise or dobutamine infusion. Exercise echocardiography is difficult to perform because of movement problems and there is quite high inter-reporter variability, but both techniques can approach the accuracy of sestamibi testing in experienced hands. It is not possible to obtain images of adequate quality in all patients. Coronary angiography (cardiac catheterisation) This procedure enables the cardiologist to visualise the coronary arteries It is the standard against which other less-invasive investigations are assessed. Selective catheterisation of the right and left coronary ostia is performed. Contrast is then injected into the vessels and digital tape or disc storage of the images obtained. In most hospitals the patient is admitted on the morning of the test and allowed to go home that afternoon. The procedure is most often performed through the femoral artery (Judkins technique) . This artery can be punctured through the skin under local anaesthetic. A fine softtipped guide wire is then advanced into the artery and the needle withdrawn (Seldinger method). A short guiding sheath can then be placed over the wire and long cardiac catheters advanced through this sheath along a long guide wire into the femoral artery and up via the aorta to the aortic arch. The catheter and wire are advanced under X-ray control. Usually one catheter with a curved tip (pig-tail catheter;is advanced across the aortic valve into the left ventricle where left ventricular pressures are measured via a pressure transducer connected to the other end of the catheter. Measurement of the left ventricular end-diastolic pressure gives an indication of left ventricular function. Raised end-diastolic pressure (over 15 mmHg) suggests left ventricular dysfunction . The catheter is then connected to a pressure injector. This enables injection of a large volume of contrast over a few seconds; for example, 35 mL at 15 mL/second. X-ray recording during injection produces a left ventriculogram Here left ventricular contraction can be assessed and the ejection fraction (percentage of end-diastolic volume ejected with each systole) estimated. The normal is 60% or more. The figure obtained by this method tends to be higher than that produced by the nuclear imaging method—gated blood pool scanning. The guide wire is reintroduced and the catheter withdrawn to be replaced by one shaped to
THE BEST CARDIOLOGISTS IN YELAHANKA Pulmonary hypertension Pulmonary hypertension is an uncommon but important cause of dyspnoea. Many patients with this chronic and often severe illness will have raised pulmonary artery pressures as a result of a cardiac or respiratory illness. Other patients may present with increasing dyspnoea without an obvious cardiac or respiratory problem. Idiopathic (primary) pulmonary hypertension (IPH) is diagnosed only when other causes of pulmonary hypertension have been excluded. By definition, pulmonary hypertension is present when the mean pulmonary artery pressure (PAP) exceeds 25 mmHg at rest or 30 mmHg during exercise. The classification of pulmonary hypertension has been revised. The Venice classification was released in 2003. The term ‘primary pulmonary hypertension’ has been replaced with ‘idiopathic pulmonary hypertension’ Patients may have used fenfluramine or phenermine (appetite-suppressing drugs), or both. Use of these drugs for long periods has been associated with the greatest risk of developing pulmonary hypertension. In cases of IPH there may be a family history (6%; autosomal dominant condition with incomplete penetrance, 20–80%). The majority of familial cases are associates with a mutation on the BMPR2 gene. There may be associated symptoms including fatigue, chest pain, syncope and oedema. Cough and haemoptysis can be present. 270 PRACTICAL CARDIOLOGY The examination may help in assessing the severity of the patient’s dyspnoea as he or she undresses. Try to work out the patient’s functional class from the history and examination (p. 256) (NYHA I–IIII, often called the NYHA–WHO class when related to pulmonary hypertension). There may be signs of chronic lung disease or congenital heart disease, or specific signs of pulmonary hypertension and right heart failure (p. 257). Investigations are directed at finding an underlying reason for pulmonary hypertension— idiopathic pulmonary hypertension is a diagnosis of exclusion—and at assessing its severity and potential reversibility. The chest X-ray is abnormal in 90% of IPH patients. It may show pulmonary fibrosis or an abnormal cardiac silhouette—RV dilatation. There may be large proximal pulmonary arteries that appear ‘pruned’ in the periphery, and the heart may appear enlarged because of right ventricle dilatation) Respiratory function tests may show a normal, restrictive or obstructive pattern. Moderate pulmonary hypertension itself is associated with a reduction in the diffusing capacity for the carbon monoxide test (DLCO) to about 50% of predicted. On the ECG look for signs of right heart strain or hypertrophy, which are present in up to 90% of patients The blood gas measurements may show hypercapnia—elevated pCO2 in hypoventilation syndromes—but hypocapnia is more common in IPH because of increased alveolar ventilation. Mild hypoxia (reduction in pO2) may be present in IPH, and is more severe when pulmonary hypertension is secondary to lung disease. On CT pulmonary angiogram (CTPA), ventilation/perfusion (V/Q) lung scan or Doppler venograms look for a deep venous thrombosis (DVT) and PE and assess the extent of involvement of the pulmonary bed. A high-resolution CT scan of the lungs is the best way of looking for interstitial lung disease. The six-minute walking test predicts survival and correlates with the NYHA–WHO class. Reduction in arterial oxygen concentration of more than 10% during this test predicts an almost threefold mortality risk over 29 months. Patients unable to manage 332 m in six minutes also have an adverse prognosis.
PAPULAR CARDIOLOGISTS IN HEBBALA ECG interpretation: points to remember 1 ECG reports should be short and based on clinical information where possible. 2 Check that the patient’s name is on the ECG and that the paper speed and calibration markers are correct. 3 Measure or estimate the heart rate—3 large squares = 100/minute. 4 Establish the rhythm. Look for P waves (best seen in L2). Are the P waves followed by QRS complexes? Look for anomalously conducted or ectopic beats. 5 Measure the intervals: PR, QRS duration and QT interval (for the latter, consult tables, but normal is less than 50% of the RR interval). 6 If the QRS complex is wide (> 3 small squares) consider the possibilities: LBBB, RBBB, WPW or ventricular rhythm or beats. If the pattern is of LBBB, there is no need in most cases to attempt further interpretation. 7 Estimate the QRS axis. In LAD, L1 and aVF diverge and L2 is predominantly negative. In RAD, L1 and aVF converge, while L2 matters little. Indeterminate axis is diagnosed when all six frontal leads are (more or less) equiphasic. 8 Check whether the criteria for LAHB or LAFB have been met. 9 Look for pathological Q waves. In general these are longer than 0.04 seconds and are more than 25% of the size of the following R wave.
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