The P Wave

Note that the P wave corresponds to electrical impulses not mechanical atria contraction. Atrial contraction begins at about the middle of the P wave and continues during the PR segment. The PR Segment PR segment is the portion on the ECG wave from the end of the P wave to the beginning of the QRS complex, lasting about 0.1 seconds. The PR segment corresponds to the time between the end of atrial depolarization to the onset of ventricular depolarization. The PR segment is an isoelectric segment, that is, no wave or deflection is recorded. During the PR segment, the impulse travels from the AV node through the conducting tissue (bundle branches, and Purkinje fibers) towards the ventricles. Most of the delay in the PR segment occurs in the AV node. Although the PR segment is isoelectric, the atrial are actually contracting, filling the ventricles before ventricular systole.

The QRS Complex In normal sinus rhythm, each P wave is followed by a QRS complex. The QRS complex represents the time it takes for depolarization of the ventricles. The Q wave is not always present. The R wave is the point when half of the ventricular myocardium has been depolarized. The normal QRS duration range is from 0.04 sec to 0.12 sec measured from the initial deflection of the QRS from the isoelectric line to the end of the QRS complex.

Normal ventricular depolarization requires normal function of the right and left bundle branches. A block in either the right or left bundle branch delays depolarization of the ventricles, resulting in a prolonged QRS duration.

The ST Segment The ST segment represents the period from the end of ventricular depolarization to the beginning of ventricular repolarization. The ST segment lies between the end of the QRS complex and the initial deflection of the T-wave and is normally isoelectric. Although the ST segment is isoelectric, the ventricules are actually contracting.

The T Wave The T wave corresponds to the rapid ventricular repolarization. The wave is normally rounded and positive.

Earth Day Canada president Jed Goldberg has identified his top 10 actions to make every day Earth Day.

1. Think before you act. Shopping has become a form of entertainment. While it can be difficult to avoid the seduction of advertising, Goldberg advises to think about what you need, not what you want, before you buy.

2. It’s all about conservation. Goldberg says we need to make the shift from being “consumers” to “prosumers” – producing consumers – to conserve energy and resources. Planting a garden is a great way to start.

3. Go vegetarian one day a week. Meat production has a huge environmental impact. Eating lower on the food chain just one day a week helps to conserve water, reduce greenhouse gas emissions and preserve valuable farmland.

4. Rethink convenience. Goldberg says people do things because they perceive that it’s easier, but easy isn’t always what’s best. Doing things in an environmentally responsible way can ultimately end up being more convenient and much cheaper, too! One example, stop buying bottled water and use tap water instead.

5. Eat and shop locally. Most of our food travels thousands of kilometres to get to our dinner plates. Ditto for our clothing and other consumers goods. Supporting local businesses also helps to build strong local communities.

6. Vote with your dollar. Advertisers and producers are conscious of what consumers want says Goldberg. Take the time to express your opinion to store owners with your wallet and your voice.

7. Use active transportation. Whether it’s walking, cycling or rollerblading, when you use your body to get from A to B instead of a motorized vehicle, you not only get the benefit of improved fitness while reducing your environmental impact, but you get to experience your community.

8. Borrow, don’t buy. Consider renting, borrowing or sharing what you need.

9. Refashion your yard. Instead of trying to achieve the perfect, lawn, why not get rid of the lawn altogether. Plant native shrubs, wildflowers or a vegetable garden. You’ll use fewer resources and free yourself from the lawnmower, too!

10. Use your sphere of influence. Collectively we have a great influence over our politicians, says Goldberg. Engage your family, friends, coworkers and community.

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The American Diabetes Association has the duty of looking for information regarding this important medical condition. 23.6 million individuals living in America currently have diabetes, and because of this the country is seen as very unhealthy. Ninety percent of this figure has been diagnosed with Type 2 diabetes. Diabetes and the tendency to be overweight usually run in the family. If there is too much glucose in your body, it could result in serious internal organ damage and affect one’s nervous system.

Living with Diabetes

A life with Type 2 diabetes is best lived in a healthy way. Diabetics will find that healthy practices will have a huge effect on them. Simple actions like eating healthy food and exercising are considered as healthy practices. Keeping the levels of your glucose within the appropriate range ensures you stay away from health complications.

To check the levels of blood glucose in your body, you can do the common finger prick test. Physicians say that such a test is comparable to the HbA1c test when tracking the glucose fluctuations in your body. This HbA1c test works by determining how high your glucose levels are and by identifying the blood’s exact glycated hemoglobin percentage. According to results of the A1c tests, people who have diabetes maintain their levels at seven percent. A seven percent maintaining level of a1c, according to the CDC, can dramatically reduce the risks of this disease by around forty percent.

Too-Tight Controls

Many studies in the medical field show that if your a1c levels are below seven percent it could mean a bad thing. People who use insulin and people who have median a1c levels have a higher death risk, according to the Seattle Lancet and Swedish Medical Center’s studies. Other tests maintain that keeping your a1c level at seven percent is still on the healthy side. Accredited endocrinologist Matt Davies shares that seven percent is healthy but it is still important for physicians to consider a patient’s medical history before implementing treatment.

About the Author – Kristina Ridley writes for the bloodless glucose meter blog , her personal hobby blog focused on healthy eating and tips to measure blood glucose levels at home to help people understand early diabetes symptoms.

SmartOne ECG is a self-service consumer portable heart monitor for checking abnormal heart rhythms.

The device can safely measure electrical activities of the heart using one’s finger tips without the need for any trained technician.Upon placing thumbs on the sensor panel of the portable ecg machine,a digital output of the heart rhythm is displayed.If the reading displays any abnormal heart rhythm,it indicates the user the type of abnormal heart rhythm.Atrial fibrillation is an important risk factor for stroke.

According to the WHO,15 million people worldwide suffer a stroke. Of these, 5 million die and another 5 million are left permanently disabled, placing a burden on family and community.

The FDA advised patients currently taking Invirase that they should not stop taking the drug, but to discuss any questions or concerns they have about Invirase with their doctors.

As well, the FDA said patients should review their cardiovascular medical history and current medications with their doctors to determine if they should continue using Invirase, and report any side-effects.

FDA’s preliminary analysis of clinical trial data from Invirase’s manufacturer, Roche, suggests the drug combination can lead to irregular heart rhythms that can cause lightheadedness, fainting and in some cases death.

The heart rhythm problem occurred in healthy patients aged 18 to 55 who were taking 1,000 mg of Invirase boosted with 100 mg of Norvir. The side-effects depended on the dose, FDA said.

The FDA is still reviewing the magnitude of the effects and their clinical implications.

What are arrhythmias?

Arrhythmias (or dysrhythmias) are problems that affect the electrical system of the heart muscle, producing abnormal heart rhythms. They can cause the heart to pump less effectively.

The heart has four chambers. The top two are the atria, and the lower two are the ventricles. Normally the heartbeat starts in the right atrium when a special group of cells sends an electrical signal. (These cells are called the sinoatrial or SA node, the sinus node or the heart’s “pacemaker.”) This signal spreads throughout the atria and to the atrioventricular (A-V) node. The A-V node connects to a group of fibers in the ventricles that conduct the electrical signal. The impulse travels down these specialized fibers (the His-Purkinje system) to all parts of the ventricles. The electrical signal must follow this exact route for the heart to pump properly.

Under some conditions almost all heart tissue can start a heartbeat. In other words, another part of the heart can become the pacemaker. An arrhythmia occurs…

• when the heart’s natural pacemaker develops an abnormal rate or rhythm.
• when the normal conduction pathway is interrupted
• when another part of the heart takes over as pacemaker
• When Medications can interrupt heart rhythms.

When any test or an diagnostic evaluation is ordered by the physician,it is most often taken as a true representation of what is really going on with the patient,when in reality it is an error.These tests may not reflect on truly what is going on with the patient.When any test is performed on the patient,two important concerns are safety and efficacy.The other important criteria is cost of the investigation.In the current era of rising costs,combing the two factors is critical for effective patient management.

The efficacy of a diagnostic test should be measured in terms of the test’s safety, its technical quality, its accuracy, its therapeutic impact, and its impact on the health of the patient (Fineberg et al. 1977).

The second stage of an efficacy assessment is to define the test’s diagnostic accuracy. In this regard, three commonly used expressions are true-positive rate, truenegative rate, and accuracy. The true-positive rate, or sensitivity, is a measure of the test’s ability to detect disease correctly when it is present. The true-negative rate, or specificity, measures the test’s ability to exclude disease in those patients who do not have it. Accuracy is the proportion of test results that are correct (true-positive results plus truenegative results divided by the total number of test results) when the test is used in a specified population. Thus, it is a reflection of both the sensitivity and the specificity of the test.To call a test result a true positive or a true negative, one must determine the true state of the patient. This is usually accomplished by doing another test, called the “gold standard,” which is considered sufficiently reliable to reveal the true state of the patient, and either confirm or refute the study test result. For example, coronary angiography has been used to verify the presence of coronary artery disease in patients participating in an efficacy study of the stress electrocardiogram. For an ideal test, there should be little disagreement between its result and the result of the “gold standard”: the test should have both high sensitivity and high specificity.

Although quantitative measures of test performance are important, a study of efficacy should not focus solely on its technical aspects (that is, on the machine). Rather, an assessment should include data on diagnostic impact and on therapeutic impact, including outcomes that are relevant to the patient. These are the third and fourth levels of an efficacy assessment.

The following questions needs to be asked by the patient to their health care provider before any diagnostic tests are performed on them:

1.Does the result of the technique change the diagnosis?

2.Does the technique add clinically significant information?

3.Is the diagnostic impact one that changes my management?

Do you have any experience with diagnostic tests?Share your experience !!

Assessment of diagnostic technology in health care: rationale, methods & Directions-Monograph By Harold C. Sox