226 - 250 of 288
Number of results to display per page
TitleDescriptionSubjectCollection
226 Long QT IintervalLong QT IntervalKnowledge Weavers ECG
227 Reduction of acetoacetateAcetoacetate is reduced by NADH in a reversible reaction catalyzed by beta-hydroxybutyrate dehydrogenase. This reaction is the source of beta-hydroxybutyrate in the blood of individuals with ketosis.Knowledge Weavers Fatty Acids
228 ECG of the century - part II: dual AV pathwaysAn astute cardiology fellow, yours truly, went to the patient's bedside on Day 2 and massaged the right carotid sinus as indicated by the arrow. Four beats later at a slightly slower heart rate the PR interval suddenly normalized suggesting an abrupt change from a slow AV nodal pathway to a fast AV...Knowledge Weavers ECG
229 Left Atrial Enlargement & Nonspecific ST-T Wave AbnormalitiesLAE is best seen in V1 with a prominent negative (posterior) component measuring 1mm wide and 1mm deep. There are also diffuse nonspecific ST-T wave abnormalities which must be correlated with the patient's clinical status. Poor R wave progression in leads V1-V3, another nonspecific finding, is als...Knowledge Weavers ECG
230 Atrial flutter with 3:2 AV conductionThis 12-lead ECG shows a subtle bigeminal rhythm resulting from atrial flutter with a 3:2 AV conduction ratio; RR intervals alternate by a small duration. This is uncommon! The impulses from the atrial flutter conduct through the AV junction in a Wenckebach sequence; for every 3 flutter waves the s...Knowledge Weavers ECG
231 A very subtle 1st degree AV blockWhere are the P waves??? They are hiding in the T waves as indicated by the arrows. How do we know? The PVC unmasked the sinus P wave, and now it is seen in the pause following the PVC. The PR interval is, therefore, about 500 ms.Knowledge Weavers ECG
232 PAC's with and without aberrant conduction - marquettePAC's with and without aberrant conduction - marquetteKnowledge Weavers ECG
233 Hydroxymethylglutaryl CoA synthase reactionThis irreversible reaction occurs in the mitochondria, where it is the first step in ketone body synthesis. It also occurs in the cytoplasm, where it leads to isoprenoid and steroid synthesis.BiosynthesisKnowledge Weavers Fatty Acids
234 Ventricular fibrillation - marquetteVentricular fibrillation - marquetteKnowledge Weavers ECG
235 Nonconducted PAC - marquetteNonconducted PAC - marquetteKnowledge Weavers ECG
236 Thiolase reactionThiolase (3-ketoacyl CoA thiolase) cleaves a long chain fatty acyl CoA, forming acetyl CoA and a long chain fatty acyl CoA that is two carbons shorter.Knowledge Weavers Fatty Acids
237 Trifascicular block: RBBB, LAFB, and mobitz II 2nd degree AV blockA nice example of trifascicular block: Lead V1 shows RBBB; Lead II is mostly negative with an rS morphology suggesting left anterior fascicular block. Since Mobitz II 2nd degree AV block is more often located in the bundle branch system, the only location left for this block is the left posterior ...Knowledge Weavers ECG
238 2nd degree AV block, type I, with junctional escapesJunctional escapes are passive, protective events whenever the heart rate slows below that of the escape mechanism. In this example of 2nd degree AV block, type I, the escapes occur following the non-conducted P waves. Arrows indicate the position of the P waves. Note that the escape beats have a...Knowledge Weavers ECG
239 Atrial flutter with 2:1 AV conductionAtrial flutter with 2:1 AV block is one of the most frequently missed ECG rhythm diagnoses because the flutter waves are often hard to find. In this example two flutter waves for each QRS are best seen in lead III and V1. The ventricular rate at 150 bpm should always prompt us to consider atrial fl...Knowledge Weavers ECG
240 Identification of PVC's and PAC'sPVC's usually stick out like sore thumbs; PAC's are often difficult to see because they are hidden in the preceding ST-T wave. The PVC in this example is mostly negative in lead V1 suggesting RV origin; i.e., most of activation is moving in posterior direction towards the left ventricle.Knowledge Weavers ECG
241 AV dissociation by defaultThe nonconducted PAC's set up a long pause which is terminated by ventricular escapes; note the wider QRS morphology of the escape beats indicating their ventricular origin. Incomplete AV dissociation occurs during the escape beats, since the atria are still under the control of the sinus node.Knowledge Weavers ECG
242 Lead error: V1 and V3 are transposed!In the precordial leads the V1 and V3 chest electrodes are interchanged. Experienced ECG interpreters should be able to spot this lead placement error.Knowledge Weavers ECG
243 Infero-posterior MI & RBBB: Frontal Plane Leads + V1Infero-posterior MI & RBBB: Frontal Plane Leads + V1Knowledge Weavers ECG
244 WPW Type Pre-excitation: Precordial LeadsWPW Type Pre-excitation: Precordial LeadsKnowledge Weavers ECG
245 Acute anterior MIAcute anterior MIKnowledge Weavers ECG
246 2nd degree AV block, type I with escapes and capturesOften in the setting of 2nd degree AV block the pauses caused by nonconducted P waves are long enough to enable escape pacemakers from the junction or ventricles to take over. This example illustrates junctional escapes, labled E and captures, labled C. Note that the PR intervals for the captures ...Knowledge Weavers ECG
247 Ventricular paced rhythm with retrograde wenckebachRetrograde atrial captures from a ventricular paced rhythm are occurring with increasing R-P intervals; i.e., retrograde Wenckebach. The ladder diagram indicates that after the blocked retrograde event, a single sinus P wave is seen dissociated from the ventricular rhythm.Wenckebach AV BlockKnowledge Weavers ECG
248 Nonconducted PAC's: an unusual bigeminyOccasionally nonconducted PAC's can create interesting rhythms. In this example every other sinus beat is followed by an early, nonconducted PAC. The resulting pause sets up a bigeminal rhythm. Note the distortion of the T waves caused by the nonconducted PAC's.Knowledge Weavers ECG
249 Atrial flutter with 2:1 AV conduction: leads II, III, V1In leads II and III, the one of the flutter waves occurs at the end of the QRS complex and might be mistaken for part of the QRS itself; i.e., the S wave. In lead V1, the two flutter waves for every QRS are more easily identified.Knowledge Weavers ECG
250 Accelerated IVR with AV dissociation - marquetteAccelerated IVR with AV dissociation - marquetteKnowledge Weavers ECG
226 - 250 of 288