Demadex hypokalemia

In addition to the shape of the T wave, the timing of the T wave relative to the QRS complex should be evaluated by measuring the QT interval. The QT interval is measured from the beginning of the QRS complex to the end of the T wave and provides a rough estimate of the duration of ventricular depolarization until the end of repolarization. A prolonged QT interval can be observed under several conditions (Table 6. First, the QT interval can be prolonged because of a hereditary disorder called the Long QT Syndrome. Second, a number of drugs can cause QT interval prolongation (Table 6. Third, electrolyte disorders such as hypocalcemia and hypokalemia can cause QT interval prolongation. Abnormal Repolarization: T Wave Changes and the QT Interval 119 Table 6. 2: Drugs associated with QT interval prolongation Drug Class Antiarrhythmics Antihistamines Antiinfectives Antimalarials Antipsychotics Antidepressants Opiates Other Specific Drugs Amiodarone* Sotalol* Dofetilide* Ibutilide* Procainamide* Disopyramide* Terfenadine Erythromycin Clarithromycin Pentamidine Chloroqiuine Thioridazine* Chlorpromazine Haloperidol demadex hypokalemia Amitryptyline Desipramine Imipramine Methadone Probucol Droperidol * More likely to prolong the QT interval. Prominent T waves Early repolarization V4 V5 V6 V3V6, II, III, aVF Prominent T waves in demadex hypokalemia leads with larger "Hook" at the terminal QRS 120 ECG Interpretation for Everyone: An OnTheSpot Guide Figure 6. 1: Background: Patients with early repolarization will often have prominent T waves. ECG: In early repolarization the prominent T waves will be observed in the inferolateral leads.

Early repolarization should be suspected if there is the characteristic "hook" on the terminal portion of the QRS complex. In most cases, ST segment elevation will be observed in the leads with the most prominent T waves. Clinical Issues: Early repolarization is fairly common, and is observed in about 712% of the general population. Interestingly, early repolarization may be more common in athletes with a prevalence of 30% in some studies. Abnormal Repolarization: T Wave demadex hypokalemia Changes and the QT Interval 121 Prominent T waves Myocardial Injury "Localized"! wave peaking in the area of ischemia / 122 ECG Interpretation for Everyone: An OnTheSpot Guide Figure 6. 2: Background: T wave peaking demadex hypokalemia may be the first sign of myocardial injury on the ECG. Usually isolated T wave peaking is buy cheap benazepril amlodipine 5mg without rx usa rapidly replaced by ST segment elevation (although the T waves remain prominent). ECG: T wave peaking associated with myocardial injury is localized to a region supplied by a specific coronary artery and often, reciprocal ST segment changes are also observed. In the example, prominent T waves are noted in V, and V:; due to a significant lesion in the left anterior descending coronary artery. In addition, notice the accompanying subtle ST segment depression in the lateral leads (V4V6 and I) and the inferior leads (II and aVF).

Clinical Issues: The presence of localized T wave peaking is very suggestive of a significant coronary artery lesion and in the patient complaining of chest pain, serial ECGs and aggressive diagnostic evaluation is essential. Abnormal Repolarization: T Wave Changes and the QT Interval 123 Prominent T waves Hyperkalemia P waves? T wave peaking Precordial I 124 ECG Interpretation for Everyone: An OnTheSpot demadex hypokalemia Guide Figure 6. 3: Background: Generalized T wave peaking is the first sign of hyperkalemia. Peaking usually is observed when the serum K+ is >5. ECG: The first ECG sign in hyperkalemia is T waves peaking. 5 mM) the QRS complex begins to widen and ST segment elevation may be demadex hypokalemia observed (Chapter 4, Figure 4. In this example, prominent T waves are noted in V:; through V6 and leads II and I. In addition to the prominent T waves the QRS demadex hypokalemia complex is wide without Q waves due to abnormal depolarization. With careful observation, ST segment elevation in leads V, and V, is also present. Finally, atrial tissue is more sensitive to hyperkalemia than ventricular tissue. This difference leads to loss of visible P wave activity particularly at extremely high K+ levels (>8 mM). Interestingly the sinus node is still "driving" the heart and this condition is called a "sinoventricular" rhythm. Although it would be unusual for myocardial injury to have this combination of demadex hypokalemia ECG changes, again the clinician must demadex hypokalemia also take the patients symptoms into account. In hyperkalemia, chest pain is usually absent although demadex hypokalemia patients may complain of nausea and generalized weakness. Clinical Issues: Emergent treatment of hyperkalemia is reviewed in Chapter 4, Figure 4. In general once a blood sample is sent off, glucose and insulin are given. If the ECG changes are due to hyperkalemia, the ECG changes will rapidly improve. Abnormal Repolarization: T Wave Changes and the QT Interval 125 T wave Inversion Myocardial Ischemia I aVR Ja aVL iAjyv III aVF U VIV4 (Usually V2&V3) 126 ECG demadex hypokalemia Interpretation for Everyone: An OnTheSpot Guide Figure 6. 4: Background: Ischemia may also cause T wave inversion. ECG: T wave inversion is a very nonspecific finding demadex hypokalemia particularly in the lateral leads because left ventricular hypertrophy is common. However, T wave inversion in V:; and V4 should arouse suspicion of ischemia in a patient with chest pain and has been associated with disease in the left anterior descending artery. The T wave inversion is usually symmetric and fairly prominent. Clinical Issues: T wave inversion should arouse suspicion for ischemia in the patient with chest pain particularly if it is new when compared to prior ECGs.