They are used to rule out stable angina. Theyshouldn't be used in low-risk patients because they have a high false-positive probability.
They induce ischemia by various ways and then detect it by ECG, echocardiography, or radionuclide imaging.

Stress tests can be divided into:

• Exercise stress test, most commonly using a treadmill.

• Pharmacological stress tests. They are used in patients who are unable to exercise or the exercise stress test is contraindicated (like in LBBB). They are further divided based on the drug being used into:

A. Positive inotropic/chronotropic drugs like dobutamine which is a B1-receptor agonist and simulates the heart physiology during exercise (in terms of increasing the heart contractility & rhythm).

B. Vasodilators like adenosine & regadenoson (adenosine analogue). They make heart ischemia manifest via a mechanism called coronary steal.

The idea is fairly simple: Adenosie and the likes of it specifically activate the A2A adenosine receptor in the coronary vessels which causes coronary vasodilation. In terms of blood flow, normal coronary vessels are up to 400% more responsive to the vasodilatory effect of adenosine than stenotic vessels. Therefore, they dilate & the blood flow increases in them. Meanwhile, atherosclerotic coronary vessels cannot dilate properly (because they are already maximally dilated) and blood flow is stolen from these narrowed coronary vessels to normal coronary vessels. This induces symptoms of ischemia, and perfusion defects appear in cardiac nuclear imaging or as ST-segment changes on the ECG.

Syphilis (and afterwards, TB) is often nicknamed "the great imitator/masquerader" because of its protean nature. It has nonspecific symptoms that can be confused with many other diseases which make it hard to diagnose and easily misdiagnosed.

📝 Quick note
اغلب المرضى أهل CKD on dialysis يجون للطوارئ
ونسويلهم ECG
من ضمن الشغلات المهمة لازم تنتبة الها هي

Bradycardia Bradycardia Bradycardia

لا تستعجل وتنطيهم atropine بل عاملهم معاملة hyperK وانطي Calcium gluconate

👉 The only ECG sign of severe and life threatening hyperK may simply be bradycardia
👉 Bradycardia is hyperK in dialysis patients until proven otherwise

Hyperkalemia is often called "the syphilis of ECG" because it can present in so many forms; bradyarrhythmia, tachyarrhythmia, AV-block, BB block, and many others...

طبعًا الشكر موصول لدكتور يوسف نسائية على هالمعلومة القيمة

An ECG report takes the form of a description followed by an interpretation.

The description should always be given in the same sequence:
1. Rate & Rhythm
2. Conduction intervals
3. Cardiac axis
4. A description of the QRS complexes
5. A description of the ST segments and T waves.

The interpretation of an ECG indicates whether the record is normal or abnormal: if abnormal, the underlying pathology needs to be identified. One of the main problems of ECG reporting is that there is quite a lot of normal variation in the ECG which are consistent with perfectly normal hearts. Recognizing the limits of normality is one of the main difficulties of ECG interpretation.

Many ECG recorders automatically provide a report, and in these reports the heart rate and the conducting intervals are usually accurately measured. However, the description of the rhythm and of the QRS and T patterns should be regarded with suspicion. Recorders tend to ‘over-report’, and to describe abnormalities where none exist: it is much better to be confident in your own reporting.

The rhythm of the heart is best interpreted from whichever ECG lead shows the P wave most clearly. This is usually, but not always, lead II or lead V1.

It is important to remember that, as with any other rhythm, a P wave may only show itself as a distortion of a T wave

Alternative medicine thrives where modern medicine fails (to meet the patient's expectations). It lives off like a parasite, feasting on the stubborn, false hope of desperate patients.

People do not resort to alternative medicine because they are stupid or irrational, but because they are desperate and hopeless.

No amount of logic & education can convince a drowning man to stop paddling & flailing his limbs even though he knows that he can't swim and that his frantic motion is all in vain.

There are multiple criteria, but the most famous is the American College of Rheumatology (ACR) criteria. It contains 11 elements. The diagnosis of SLE is confirmed when 4 or more of the criteria have been met.

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