The ECG changes in the figure below:
are of:
On this electrocardiogram, there is a narrow complex tachycardia. The complexes are regular. In lead V1 , there is an atrial wave that has a short RP, long PR relationship. This is an example of supraventricular tachycardia or AV nodal reentrant tachycardia (AVNRT). If the atrial wave seen in V1 extends to 70 or 80 milliseconds out into the ST segment, then this type of tracing could be an example of AV reentrant tachycardia (AVRT), which usually involves a larger reentrant loop and a bypass tract.
are suggestive of:
Chronic lung disease. Here there is a narrow complex tachycardia. It is chaotically irregular and there are multiple P-wave vectors. This is not atrial fibrillation, which also is chaotic, but instead is a multifocal atrial tachycardia. This patient also shows aberrancy in the 6th and 14th beats.
Changes are:
The changes in the figure below:
Digitalis toxicity (Digitalis effect). This patient has a regular rhythm, but the baseline as seen in lead V1 is chaotic. It is an example of atrial fibrillation with a regular ventricular response. This is actually an accelerated junctional rhythm most likely caused by digitalis excess. In lead V6 there is ST-segment sagging that is smooth and associated with QT interval shortening. This suggests digitalis “effect.” Digitalis effect is seen in the repolarization changes with STsegment scooping. Digitalis “excess” is usually suggested by arrhythmias and in this case the accelerated junctional rhythm (AV junctional rhythm, accelerated rhythm (nonparoxysmal junctional tachycardia))
Cardiac transplant. This patient shows an rSR′ pattern in lead V1 that might suggest a volume-overload right ventricular hypertrophy (RVH). That is supported in part by the right axis deviation. However, in looking at the rhythm strip in lead II, there is a basic sinus rhythm with a first-degree AV block and in addition there is a second atrial rhythm that is dissociated from the basic PQRS sequence. This is accessory atrial activity related to cardiac transplantation.
The ECG in the figure below:
shows:
On this electrocardiogram, there is a regular atrial activity, but the P waves are inverted in the inferior leads, suggesting an ectopic atrial tachycardia. This conducts with group beating and gradual PR prolongation. This is an example of atrial tachycardia with Mobitz type I AV block.
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