What Is Behind The Number In Cardiovascular Deseases

Prof. Dr. Soliman Ghareeb MD.
Professor Of Cardiovascular Medicine Cairo University
What Is Behind The Number
In Cardiovascular Deseases
The numerical values are used in the evaluation, diagnosis , and management of the majority of the cardiovascular diseases like hypertension , dyslipidemia, and degree of coronary arteries stenosis . the problem is that the same number may be shared in the different patients with the same etiology but with different prognoses in each of them.
In this article we will try to explain how we should think and use the available numerical value in the diagnosis , management, and prognosis Of cardiovascular diseases.
1- Shortness of breath
Normal respiratory rate is about 16/min. and this means that the normal subject should take one respiration every 3-4 second . therefore if any one who came with a complaint of shortness of breath can hold respiration for more than 10 second ,this subject for sure has psychological shortness of breath rather than a reflection of organic disease. We should think on diagnosis of pulmonary embolism if we have Patient present with shortness of breath ,chest discomfort or pain and ABG showed hypocabnia, hypoxia, and hypotension.
2- Chest Pain History
In the Coronary Artery Surgery Study (CASS) chest pain history was found to predict significant CAD in women 72% of the time, whereas the same history in men was predictive of significant CAD 93% of the time.
Despite the fact that Chest pain is the main symptoms for diagnosis of coronary artery insufficient but In Holter monitor studies 92% of all ischemic episodes are silent and in clinical follow up study - Framingham Study -in 30-50 years patients the first coronary events is myocardial infarction(MI) without any previous chest pain. And Unexpectedly Most Myocardial Infarctions are Caused by Low-Grade Stenosis wheares 65% of those who developed MI has angiographic determined coronary artery lesion less than 50% . for this reasons we do investigations like exercise test to diagnose myocardial ischemia
in the exercise test should be considered as positive for Ischemic changes if there is:
1. typical chest pain. Without ECG ST changes
2. decreases in the BP. Despite the absent of ECG changes
3. Normalization of a depressed ST whereas normalization is probably due to ST elevation associated transmural ischemia.
with Exercise ECG High Risk Predicted if
● Inability to complete 6 min. of Bruce protocol.
● Early positive test results ( ● Strongly positive result(> 2 mmST depression).
● Sustained ST depression> 3min in
recovery.
● Ischemia at low heart rate ● Serious ventricular arrhythmia at HR 3- Obesity
It is estimated that 280,000 to 325,000 deaths a year can be attributed to obesity in the United States, more than 80% of these deaths occur among individuals with a BMI greater than 30 kg/m2. In addition to overweight and central fatness, the amount of weight gain after ages 18 to 20 also predicts mortality. A sedentary lifestyle increases the risk of death at all levels of BMI. i.e. it is not absolutely a matter of BMI .s
4-Heart rate
Heart rate is normally determined by the pacemaker activity of the sinoatrial node (SA node) located in the posterior wall of the right atrium which exhibits its automaticity. This intrinsic automaticity, if left unmodified by neurohumoral factors, exhibits a spontaneous firing rate of 100-115 beats/min. This intrinsic firing rate decreases with age,
Normally, at rest, there is significant vagal tone on the SA node so that the resting heart rate is between 60 and 80 beats/min. The maximal heart rate that can be achieved in an individual is estimated by Maximal Heart Rate = 220 beats/min − age in years Therefore a 20-year-old personwill have a maximal heart rate of about 200 beats/min, and this will decrease to about 170 beats/min when the person is 50 years of age.
Physiologically HR increases by 15 bpm for each rises of one degree body temperature Except in typhoid fever whereas such proportionate increase don't occur. In normal subject for every increase of 5 bpm in HR there will be increase incidence of coronary events by 1.14 fold., while in patients with stable CAD data confirmed through holter monitoring showed HR as high as 80 bpm is associated with double the risk of developing ischemic attacks versus 60 bpm. 1–year mortality In post myocardial infarction patients, was increased with increasing heart rate from 60 to 80 bpm by 10% and by 20% at a heart rate above 100 beats/min( Göteborg-Trial and the GISSI-3). In patient with Aortic regurgitation Increase of HR indicates chronicity its increase has a correlation with the prognosis together with LVESD as measured by echocardiography.
4- BP
control of BP level per se is the main target in management of hypertension. benefits of lowering BP is to decrease stroke incidence by 40% ,HF by 50%, and MI by 25% but the problem in the management of HTN is the number as an examples a BP of 165/95mmHg showed Mean Absolute Risk to develop CVS of 8 (%) if patient has no other risk factors while this absolute risk increase up to 27% if the patient has LDL more than 155mg/dl, age above 56 years, and smoke cigarette.
in diabetic persons A10-mmHg increase in systolic BP (SBP) leads to:15% increase in death related to diabetes, 11% in myocardial infarctions, 19% in stroke, and 12% in congestive heart failure. (Adler et al., 2000).
5- MsctCoronary Angiocoronary CalciumScoring
● Presence of any coronary artery calcium( CAC ) is associated with fourfold risk of coronary events over 3-5 years but multiple follow up studies proved that Detection of large score does not imply significant stenosis, Because Not every atherosclerotic plaque is calcified !!. So, Calcium scoring is Inappropriate for risk stratification of patients with CAD but it indicates low sensitivity of MSCT angio . if the score is very high.(Haberl et al. jack. 2001)
6-dyslipidimia
Several overlooked facts should be discussed under this item like:
TRANS-Fats: Trans-fats are formed by high temperature cooking using any type of unsaturated fat (oil). It leads to raise LDL and lower HDL and On a program basis, trans fats are worse than saturated fats. Another fact is that 35% of CHD Occurs in People with TC Importantly, triglycerides are not just an independent risk factor for CHD, they also exhibit a synergistic relationship in terms of increased CHD risk, as shown by the PROCAM study.which showed at any level of LDL, an elevated level of triglycerides further increases the risk of CHD. And Every 1 mmol/L (88.5 mg/dl) increase in triglycerides increases risk of CHD by 32% in men and 76% in women
In conclusion: in the management of cardiovascular diseases careful analysis of the numbers either during history taking ,clinical axamination or analysing the investigations is mandatory to avoid misdiagnosis, and to insure proper and correct management.