Complete Heart Block (CHB) ? Think Again

No clinical hx. Is this complete heart block (CHB)?

Image 1

This is sinus rhythm (SR) at about 88 bpm, first degree AV block, second degree advanced heart block or high-degree AV block, right bundle branch block.

It is very tempting to call this CHB. However, the clue that a sinus P wave is conducted is the irregularity of RR interval. There is sudden shortening of the RR interval (R4R5) vs the rest of the RR interval. If this is CHB the RR interval would be the same in all because in CHB the ventricles will be under the control of an ectopic junctional or ventricular focus. So, it would beat like clockwork. If there was shortening or difference in the RR interval, this means that a sinus impulse was conducted.

A simple trick to differentiate CHB from advanced heart block is the regularity of the RR interval. 

Complete Heart Block

Adult w/ h/o HTN, CAD and DM c/o dizziness. Trop negative, BNP 8000 lytes - N

Image - ECG case

The 12 lead ECG shows sinus rhythm SR (atrial rate ~88 bpm) and a regular narrow (junctional) escape beats (~30's). This is complete heart block.

Eventually a permanent pacemaker is inserted.


#504 

STEMI (IWMI) and Complete Heart Block

An elderly with h/o of HTN and DM II c/o chest discomfort. 

Figure 1

Complete heart block with junctional escape rhythm

Image 1

Complete heart block will always have REGULAR VENTRICULAR BEATS(escape beats either ventricular or junction in origin). If the RR interval is irregular then some of the supraventricular impulses are conducted. Hence, not CHB. 

Image 2 - ladder diagram

For this strip:

Sinus rhythm with complete heart block with junctional escape rhythm

#183

From the ECG vault

What is your interpretation?

Image 1

This is an irregular rhythm with no P to QRS relationship. The QRS duration is about 0.10 sec as measured using aVR. 

Lead I is predominantly positive and aVF is predominantly negative  or there is left axis deviation. There is qR pattern  in aVL and there is rS pattern in II, III and aVF. This QRS morphology suggest left anterior fascicular block (LAFB).

Image 2

As to the P waves, there is a bigeminal pattern. Bigeminal pattern P waves can be seen in PAC in bigeminy or sinoatrial block. 

Without R3 and R7, the pattern is of complete heart block (CHB) with a junctional escape with LAFB. R3 and R7 could  be premature junctional beats conducted with LAFB. R3 and R7 cannot be PAC's because supraventiruclar impulse cannot be conducted in CHB.

So, this is sinus rhythm with bigeminal pattern probably sinoatrial block, complete heart block with junctional escape conducted  with LAFB and premature junctional complexes.

* If you have another probable explanation, feel free to post. As seasoned ECG reader would say, an ECG can have multiple possible explanations. 

AV block is more common in IWMI

Vignette: 65 yo with h/o  HTN, DM, dyslipidemia 

c/o of chest pain

Image 1

The rhythm is sinus tachycardia at about 107 bpm with complete heart block (CHB) with a junctional escape rhythm (50 bpm). There are ST elevations in II, III and aVF with ST depression more pronounced in aVL than I. ST-T wave changes can be seen in precordial leads extending to V4. This is inferior wall STEMI (IWMI)with  complete heart block. AV block is more common in IWMI because the AV node is  supplied by the right coronary artery (RCA).

Image 2

P waves are marked. Some of the P waves are (partly) hidden from view (blue arrowheads)

Echo showed EF between 45 - 50 %,with severe inferior and inferolateral  hypokinesis. Angiogram revealed lesion in the RCA and intervention was done.Patient was discharged a few days later in sinus rhythm (with no CHB). 

#585