Dr. Arun RamaGiri Nair

05/07/2020

27/03/2020

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know Corona virus

22/09/2019

22/09/2019

Smoking is injurious to health

Cigarette smoke is a complex mix of more than 4000 chemicals, some smoke components, such as carbon monoxide (CO), hydrogen cyanide (HCN), and nitrogen oxides, are gases. Others, such as formaldehyde, acrolein, benzene, and certain N-nitrosamines, are volatile chemicals contained in the liquidvapor portion of the smoke aerosol. Still others, such as ni****ne, phenol, polyaromatic hydrocarbons (PAHs), and certain to***co-specific nitrosamines (TSNAs), are contained in the submicron-sized solid particles that are suspended in cigarette smoke.

In view of this chemical complexity, cigarette smoke has multiple, highly diverse effects on human health. It is not unexpected that multiple chemicals in cigarette smoke can contribute to any single adverse health effect. Smoking is a major risk factor for cardiovascular morbidity and mortality, and is considered to be the leading preventable cause of death in the world.

Physical and biochemical properties of cigarette smoke

Conventionally, cigarette smoke is divided into two phases: a tar phase and a gas phase. The tar or particulate phase is defined as the material that is trapped when the smoke stream is passed through the Cambridge glass-fiber filter that retains 99.9% of all particulate material with a size >0.1 μm . The gas phase is the material that passes through the filter. The particulate (tar) phase of cigarette smoke contains >1017free radicals/g, and the gas phase contains >1015free radicals/puff . The radicals associated with the tar phase are long-lived (hours to months), whereas the radicals associated with the gas phase have a shorter life span (seconds).

Cigarette smoke that is drawn through the to***co into an active smoker's mouth is known as mainstream smoke. Sidestream cigarette smoke is the smoke emitted from the burning ends of a cigarette. Mainstream cigarette smoke comprises 8% of tar and 92% of gaseous components. Environmental to***co smoke results from the combination of side stream smoke (85%) and a small fraction of exhaled mainstream smoke (15%) from smokers. Side stream cigarette smoke contains a relatively higher concentration of the toxic gaseous component than mainstream cigarette smoke. Of all the known constituents, ni****ne, a component of the tar phase, is the addictive substance of cigarette smoke.

Ni****ne

Ni****ne is classed as an alkaloid (like morphine and co***ne) and meets the criteria of a highly addictive drug. One cigarette delivers 1.2-2.9 mg of ni****ne, and the typical one pack-per-day smoker absorbs 20-40 mg of ni****ne each day. As an addictive drug, ni****ne has 2 very potent effects: it is a stimulant and it is also a depressant. Ni****ne deregulates cardiac autonomic function, boosts sympathetic activation, raises heart rate, causes coronary and peripheral vasoconstriction, increases myocardial workload, and stimulates adrenal and neuronal catecholamine release. In addition, ni****ne is associated with insulin resistance, increased serum lipid levels, and intravascular inflammation that contributes to the development of atherosclerosis.

Reference

http://www.hsj.gr/medicine/effects-of-smoking-on-cardiovascular-function-the-role-of-ni****ne-and-carbon-monoxide.php?aid=2732
https://ars.els-cdn.com/content/image/1-s2.0-S0735109704004346-gr1.gif
https://www.medscape.com/viewarticle/577468

14/09/2019

Hypertension and Heart

Hypertension is also known as high blood pressure. It is defined as transitory (short-lived) or chronic elevation of the blood pressure in the arteries. This elevation may lead to cardiovascular damage.

The heart and hypertension are intimately linked. Hypertension predisposes to coronary heart disease, myocardial hypertrophy, and cardiac dysfunction. The impact of hypertension on the heart is much more important than its effect in causing stroke and renal failure in terms of numbers of patients affected. There is still undue emphasis on diastolic pressure, with little attention paid to isolated systolic hypertension, and treatment remains inadequate for many patients.

Longstanding hypertension ultimately leads to heart failure (HF), and, as a consequence most patients with HF have a history of hypertension. Conversely, absence of hypertension in middle age is associated with lower risks for incident HF across the remaining life course. Cardiac remodeling to a predominant pressure overload consists of diastolic dysfunction and concentric left ventricular (LV) hypertrophy. When pressure overload is sustained, diastolic dysfunction progresses, filling of the concentric remodeled LV decreases, and HF with preserved ejection fraction ensues. Diastolic dysfunction and HF with preserved ejection fraction are the most common cardiac complications of hypertension. The end stage of hypertensive heart disease results from pressure and volume overload and consists of dilated cardiomyopathy with both diastolic dysfunction and reduced ejection fraction. “Decapitated hypertension” is a term used to describe the decrease in blood pressure resulting from reduced pump function in HF. Progressive renal failure, another complication of longstanding hypertension, gives rise to the cardiorenal syndrome (HF and renal failure). The so-called Pickering syndrome, a clinical entity consisting of flash pulmonary edema and bilateral atheromatous renovascular disease, is a special form of the cardiorenal syndrome.
Blood pressure (BP) is classified as follows by the American

Heart Association:
Normal BP: Systolic less than 120 mm Hg; diastolic less than 80
Elevated BP: Systolic is between 120 and 129 mm Hg; diastolic less than 80
Stage 1 High BP: Systolic is 130–139 mm Hg or your diastolic is between 80-89
Stage 2 High BP: 140 or greater systolic, or 90 or greater diastolic

Pathophysiology
In most hypertensive patients, LV diastolic dysfunction is the first discernible manifestation of heart disease . Cardiac remodeling to a predominant pressure overload consists of concentric LV hypertrophy (increase in cardiac mass at the expense of chamber volume). In contrast, cardiac remodeling to a predominant volume overload (e.g., obesity, chronic kidney disease, anemia) consists of eccentric hypertrophy (increase in cardiac mass and chamber volume) . When pressure overload is sustained, diastolic dysfunction progresses, the concentric remodeled LV decompensates, and hypertensive HF with preserved ejection fraction (HFpEF) ensues. In contrast, when volume overload is sustained, LV dilatation progresses, the eccentric remodeled LV decompensates, and HF with reduced ejection fraction (HFrEF) ensues. The combination of LV hypertrophy with increased levels of biomarkers of subclinical myocardial injury (high-sensitivity cardiac troponin T, N-terminal pro–B-type natriuretic peptide) identifies patients at highest risk for developing symptomatic HF, especially HFrEF . The end stage of hypertensive heart disease, usually the result of longstanding pressure and volume overload, consists of dilated cardiomyopathy with both diastolic dysfunction and reduced ejection fraction.

From a clinical point of view, hypertensive heart disease can be divided into 4 ascending categories, based on the pathophysiologic and clinical impact of hypertension on the heart:
Degree I: Isolated LV diastolic dysfunction with no LV hypertrophy
Degree II: LV diastolic dysfunction with concentric LV hypertrophy
Degree III: Clinical HF (dyspnea and pulmonary edema with preserved ejection fraction)
Degree IV: Dilated cardiomyopathy with HF and reduced ejection fraction

Symptoms:
Most people with high blood pressure have no signs or symptoms, even if blood pressure readings reach dangerously high levels.

A few people with high blood pressure may have headaches, shortness of breath or nosebleeds, but these signs and symptoms aren't specific and usually don't occur until high blood pressure has reached a severe or life-threatening stage.

Diagnosis:
The best way to diagnose high blood pressure (HBP or hypertension) is to have your blood pressure measured.

Prevention & Management

• Don’t smoke and avoid secondhand smoke.
• Reach and maintain a healthy weight.
• Eat a healthy diet that is low in saturated and trans fats and rich in fruits, vegetables, whole grains, and low-fat dairy products.
• Aim to consume less than 1,500 mg/day of sodium (salt). Even reducing your daily intake by 1000 mg can help.
• Eat foods rich in potassium. Aim for 3,500 – 5,000 mg of dietary potassium per day.
• Limit alcohol to no more than one drink per day if you’re a woman or two drinks a day of you’re a man.
• Be more physically active. Aim for at least 90 to 150 minutes of aerobic and/or dynamic resistance exercise per week, and/or three sessions of isometric resistance exercises per week.
• Take medicine the way your doctor tells you.
• Know what your blood pressure should be and work to keep it at that level.

Reference:
• http://heartfailure.onlinejacc.org/content/5/8/543
• https://heart.bmj.com/content/86/4/467 -permissions
• https://www.webmd.com/hypertension-high-blood-pressure/guide/default.htm
• https://www.heart.org/-/media/data-import/downloadables/pe-abh-what-is-high-blood-pressure-ucm_300310.pdf?la=en&hash=CAC0F1D377BDB7BC3870993918226869524AAC3D
• https://www.heart.org/en/health-topics/high-blood-pressure/the-facts-about-high-blood-pressure/how-high-blood-pressure-is-diagnosed
• https://www.mayoclinic.org/diseases-conditions/high-blood-pressure/symptoms-causes/syc-20373410

07/09/2019

CORONARY ARTERY DISEASE

Introduction:

Myocardial ischaemia occurs when there is an imbalance between the supply of oxygen and the myocardial demand for these substances.

Coronary blood flow to a region of the myocardium may be reduced by a mechanical obstruction that is due to - Atheroma, Thrombosis, Spasm, Embolus, Coronary ostial stenosis and Coronary arteritis. There can be a decrease in the flow of oxygenated blood to the myocardium due to - Anaemia, Carboxyhaemoglobulinaemia and Hypotension causing decreased coronary perfusion pressure.

Sudden cardiac death is a prominent feature of CAD. One in every six coronary attacks present with sudden death as the first, last and only symptom.

Process:
Coronary atherosclerosis is a complex inflammatory process characterized by the accumulation of lipid, macrophages and smooth muscle cells in intimal plaques in the large and medium-sized epicardial coronary arteries.
Mechanical shear stresses (e.g. from morbid hypertension), biochemical abnormalities (e.g. elevated LDL, diabetes mellitus), immunological factors (e.g. free radicals from smoking), inflammation (e.g. infection such as Chlamydophila pneumoniae) and genetic alteration may contribute to the initial endothelial ‘injury’ or dysfunction, which is believed to trigger atherogenesis.

Risk factors for coronary disease:
Fixed Factors - Age, Male s*x, Positive family history, and Deletion polymorphism in the angiotensin-converting enzyme (ACE) gene (DD).
Potentially changeable factors - Hyperlipidaemia, Cigarette smoking, Hypertension, Diabetes mellitus, Lack of exercise, Blood coagulation factors – high fibrinogen, factor VII, C-reactive protein, Homocysteinaemia, Obesity, Gout, Certain Drugs, e.g. contraceptive pill, Heavy alcohol consumption.

Prevention:
There are a number of lifestyle changes or self-management steps that can be taken to prevent or reduce the risk of developing coronary heart disease. These include:

Eating a healthy, balanced diet (follow heart disease prevention diet), Limiting/ Avoid alcohol intake, Quit smoking, Undertaking regular physical exercise – 30 minutes most days of the week (follow heart disease prevention - exercise), Maintaining a healthy body weight, Maintaining healthy blood cholesterol levels, Effectively treating medical conditions such as type 2 diabetes and high blood pressure, Being aware of risk factors.

Self-awareness and education to minimise risk factors is important in helping to prevent and control coronary heart disease.

Diagnosis:
High Sensitivity C-reactive protein blood test, Electrocardiogram (ECG), Exercise ECG/ Exercise Tolerance Test (ETT), Echocardiogram, Stress Echocardiography, Angiogram, CT Angiography, Coronary calcium testing, Nuclear Isotope Imaging- techniques include: multigated radionuclide angiography (MUGA) and single photon emission computed tomography (SPECT).

Treatment:
Lifestyle changes, Medications, Coronary Angioplasty and Stenting, Coronary Artery Bypass Grafting (CABG).

Reference:
• Kumar & Clark’s Clinical Medicine.
• Harrison’s Principles of Internal Medicine
• Davidson's Principles and Practice of medicine.
• Current Medical Diagnosis & Treatment 2018.
• https://www.southerncross.co.nz/group/medical-library/coronary-heart-disease-causes-symptoms-prevention.
• https://www.hopkinsmedicine.org/health/conditions-and-diseases/coronary-artery-disease-prevention-treatment-and-research
• https://www.mayoclinic.org/diseases-conditions/heart-disease/in-depth/heart-disease-prevention/art-20046502

06/09/2019

://www.who.int/news-room/fact-sheets/detail/the-top-10-causes-of-death

06/09/2019

Principles of Care:

Ethical decisions are often called for in medical practice, at both the “micro” level of the individual patient-clinician relationship and at the “macro” level of the allocation of resources. Ethical principles that guide the successful approach to diagnosis and treatment are honesty, beneficence, justice, avoidance of conflict of interest, and the pledge to do no harm.
The clinician’s role does not end with diagnosis and treatment. The importance of the empathic clinician in helping patients and their families bear the burden of serious illness and death cannot be overemphasized. “To cure sometimes, to relieve often, and to comfort always” is a French saying as apt today as it was five centuries ago—as is Francis Peabody’s admonition: “The secret of the care of the patient is in caring for the patient.” Training to improve mindfulness and enhance patient-centered communication increases patient satisfaction and may also improve clinician satisfaction.

@ 2018 current medical diagnosis & treatment fifty - seventh edition

30/08/2019