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HEART SPECIALISTS IN H S R LAYOUT BANGALORE A systematic description of ECGs The following eight short steps will enable most ECGs to be described correctly: 1 Check the paper speed and calibration markers. 2 Measure or estimate the heart rate. 3 Estimate the rhythm. 4 Look for P waves. 5 Measure the PR interval. 6 Examine the QRS complex. 7 Check the ST segment. 8 Measure the T wave. ECG interpretation should always be as restrained as practicable, taking into account the clinical context where known and comparison with previous tracings where possible. The possibility of Prinzmetal’s electrocardiographic heart disease must always be borne in mind—that is, do not assume that an abnormal ECG always means heart disease.2 Paper speed and calibration markers The standard paper speed is 25 mm/second. This means that 1 mm (small square) = 0.04 seconds and 5 mm (large square) = 0.20 seconds. Provided that the grid is shown, this gives the time scale regardless of the actual image magnification used. Voltage is measured on the vertical axis: 10 mm = 1 mV, as shown in the calibration artefact Leads are often described in groups that correspond approximately to the area of the heart they represent. n Leads 1 and aVL are (high) lateral leads. n Leads 2, 3 and aVF are inferior leads. n Leads 1, 2, 3, aVL, aVF and aVR are collectively called limb or frontal plane leads. Leads 1, 2 and 3 are standard limb leads, while leads aVL, aVF and aVR are augmented limb leads. n Leads V1 and V2 are anteroseptal leads. n Leads V3 and V4 are anterior leads. n Leads V5 and V6 are anterolateral leads. n Leads V1–V6 are collectively called chest, precordial or horizontal plane leads. 3• AN OVERVIEW OF CLINICAL ELECTROCARDIOGRAPHY 49 Heart rate By definition, sinus tachycardia is a heart rate ≥ 100/minute and sinus bradycardia is a heart rate ≤ 50/minute.3 To calculate the heart rate from the ECG, the R-R interval in mm can be divided into 1500. For example, an R-R interval of 20 mm gives a rate of 75/minute and an R-R interval of 15 mm gives a rate of 100. Similarly, large 5 mm squares can be divided into 300; thus three squares give a rate of 100/minute. In regular rhythms, any two congruous points of the P-QRS-T sequence can be used to estimate the rate. An ECG ruler has a scale that enables rapid rate measurement and calculation of other intervals. With practice, the rate can be estimated at a glance. Rhythm Begin by looking for P waves. They are best seen in lead 2 (L2) (which is calculated electrocardiographically as the arithmetic sum of leads 1 and 3), aVR (where everything including the P waves
HEART SPEACIALIST IN BANGALORE HYPERTENTION By definition, sinus tachycardia is a heart rate ≥ 100/minute and sinus bradycardia is a heart rate ≤ 50/minute.3 To calculate the heart rate from the ECG, the R-R interval in mm can be divided into 1500. For example, an R-R interval of 20 mm gives a rate of 75/minute and an R-R interval of 15 mm gives a rate of 100. Similarly, large 5 mm squares can be divided into 300; thus three squares give a rate of 100/minute. In regular rhythms, any two congruous points of the P-QRS-T sequence can be used to estimate the rate. An ECG ruler has a scale that enables rapid rate measurement and calculation of other intervals. With practice, the rate can be estimated at a glance.
THE BEST CARDIOLOGISTS IN YELAHANKA A systematic description of ECGs The following eight short steps will enable most ECGs to be described correctly: 1 Check the paper speed and calibration markers. 2 Measure or estimate the heart rate. 3 Estimate the rhythm. 4 Look for P waves. 5 Measure the PR interval. 6 Examine the QRS complex. 7 Check the ST segment. 8 Measure the T wave. ECG interpretation should always be as restrained as practicable, taking into account the clinical context where known and comparison with previous tracings where possible. The possibility of Prinzmetal’s electrocardiographic heart disease must always be borne in mind—that is, do not assume that an abnormal ECG always means heart disease.2.
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.
A risk factor is a demographic characteristic associated with an increased risk of ischaemic heart disease when other variables have been controlled. The presence of a risk factor in an individual increases his or her relative risk of a coronary event (angina, infarction or death). The absolute risk of a coronary event depends on the individual’s total number of risk factors and theirseverity (total risk). Important coronary risk factors are shown in Table 1.1. Risk assessment charts have been developed to estimate a patient’s cardiac risk over a number of years using easily identified risk factors. There are charts for different populations. The charts can be used to predict cardiovascular events or mortality (as in the NHF chart in Fig 1.1 on p. 4) or cardiac risk (systematic coronary risk evaluation system or SCORE charts). These charts can be very helpful in deciding when intervention to reduce risk is warranted; for example, when anti-hypertensive treatment should be commenced for a patient with mild blood pressure elevation. Risk factor reduction involves assessing the presence, severity and importance of risk factors for a
THE BEST CARDIOLOGISTS NEAR HSR LAYOUT 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 fit into the right or left coronary orifice...
SAMIKSHA HEART AND DIABETIC CARE IN YELAHANKA Echocardiographic findings in certain cardiac abnormalities It is important to be aware that modern colour flow mapping is so sensitive that small amounts of regurgitation are often detected from quite normal valves. Deciding whether these jets are significant can be difficult and requires experience. Mitral stenosis Thickening and doming of the mitral valve leaflets is visible on M mode and 2D scanning , It may be possible to measure the valve area by planimetry . Secondary changes such as left atrial size and the presence of rheumatic disease of other valves can be seen. Doppler interrogation of the jet of blood entering the left ventricle through the mitral valve will enable estimation of the valve area by a formula called the pressure half-time equation This will usually give accurate and consistent estimates of the valve area and is especially useful for serial measurements over months or years. It will also be possible to detect associated mitral regurgitation with Doppler. Mitral regurgitation and mitral valve prolapse Here the mitral valve may appear normal and abnormal co-aptation of the leaflets is not usually visible . The left atrium will appear enlarged if significant chronic MR is present, and if this is severe left ventricular dilatation will be present. If the MR is due to mitral valve
CADIOLOGISTS IN VIDHYARANYAPURA 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 fit into the right or left coronary orifice. Hand injections of 5–10 mL of contrast are then made. Modern equipment enables numerous views of the coronaries to be obtained in both right and 4• THE PATIENT WITH CHEST PAIN 129 left oblique and caudal and cranial angulated views. The left system (left main, left anterior descending and circumflex arteries) is more complicated than the right, and more views are obtained ) It is also possible to catheterise the heart by direct puncture of the radial artery at the wrist, using a long sheath and a technique similar to the Judkins. Problems may be encountered advancing the catheters around the shoulder or if spasm of the radial or brachial artery occurs.
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
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