ECG Blog #543 — A 24-Hour Holter was Done ...

The ECG in Figure-1 was obtained from a previously healthy elderly woman — who presented with dizzyness and fatigue, but no CP (Chest Pain).

• Details of the timing of this patient's symptoms with respect to when the ECG in Figure-1 was recorded are uncertain.

QUESTIONS:

With the above history in mind: 

• How do YOU interpret today's initial ECG?
• Clinically — What would you do?

Figure-1: The initial ECG in today's case.

My Thoughts:

The ECG in Figure-1 shows sinus bradycardia at a rate of ~50/minute.

• The QRS is narrow — the PR interval is normal — and the QTc is probably not increased given the slow rate. 
• There may be small U waves in the mid-chest leads (which sometimes occurs in association with bradycardia).
• There is a slight leftward axis — though not negative enough to qualify as LAHB (The QRS is slightly more negative than positive in lead aVF — but mainly positive in lead aVL — which puts the axis at about -15 degrees).
• There may be voltage for LVH (Hard to say for sure if the R in aVL ≥12 mm — given overlap of this R wave in aVL with the S wave in lead aVR).

Regarding Q-R-S-T Wave Changes:

• The narrow Q waves in leads I,aVL are probably not abnormal given fairly tall R wave amplitude in these leads.
• R wave progression — looks normal, with transition (where the R wave becomes taller than the S wave is deep) occurring normally beween leads V2-V3.
• There are subtle ST-T wave abnormalities in a number of leads. As shown in lead III and in leads V1,V2,V3 — there is ST segment coving but really no elevation, followed by T wave inversion (the RED arrows in these leads).
• BLUE question marks in a number of other leads highlight ST-T wave segments of uncertain significance — especially given the different ST-T wave appearance between the only 2 complexes that we see in leads aVL and aVF — and our inability to fully see the ST-T wave of the 2nd complex in leads V4,V5,V6 (? what is real vs artifact?). That said — there appears to at least be ST segment flattening in lead II, with slight ST depression in leads V4,V5,V6.

Impression: In view of the brief history we are given, but without "being there" — it's hard to know what to think of the above described ECG changes shown in Figure-2.

• It is clearly possible that this elderly woman at some point in time (possibly recently) — had inferior and anterior infarction. That said — the lack of a history of preceding chest pain (and uncertainty about the time of this elderly patient's "dizzyness and fatigue" ) — make it difficult to know whether she may have had a "silent" MI with "chest pain equivalent" symptoms? And if so — when this may have happened? (See ECG Blog #228 — for more on "Silent" MI).
• Without a preceding history of CP that then resolved — this case does not fit criteria for "Wellens' Syndrome". That said — ECG #1 certainly could be the result of infero-antero infarction at some point in time, possibly recent (See ECG Blog #320 and ECG Blog #350 — for more on what Wellens Syndrome is, and what it is not).

Figure-2: I've labeled ECG findings in the initial ECG.

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The CASE Continues:

This elderly woman up until now had not sought out medical care. She lived alone and functioned completely independently. Although she reported dizziness and fatigue as the reason for her emergency visit — the medical care provider who treated the patient thought she looked remarkably well. As a result — ACS (Acute Coronary Syndrome) was not considered:

• Of note, the patient did not have medical insurance, and she had financial limitation. As a result — she did not want an extensive diagnostic work-up, especially given that she felt good enough to return to her independent living situation at home. 
• Troponin was not ordered.
• Instead, a 24-hour ambulatory Holter monitor was placed — and the patient went home. Follow-up was scheduled for her to return the next day.

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The Patient's Holter Monitor . . .

As you think about the challenging limitations for managing this case — what follows below in Figures-3 -thru-9 are non-sequential rhythm strips from this patient's 24-hour ambulatory Holter moniter that was reviewed the next day.

• NOTE: Each of the 6 non-sequential Holter rhythm strips that are shown below manifest 6 leads — including 1 limb lead (lead aVF) — and 5 chest leads (leads V1-thru-V5).
• As you review these 6-lead rhythm strips — Keep in mind that the only symptoms this elderly woman reported was some "dizzyness" and "mild fatigue" — but no chest pain. The 24 hour ambulatory Holter was started several hours after this woman had been evaluated. She still had no chest pain.
• For ease of comparison in Figure-3 — I've reproduced this patient's initial ECG that was shown above in Figure-2.

Figure-3: Comparison between the initial ECG — and Holter-A, recorded several hours later after the patient had returned home (at 11:16 pm — while the patient was sleeping).

My Thoughts on Holter-A:

Keeping in mind the inevitable slight differences in lead placement with 6-lead Holter monitoring vs lead placement with the patient's 12-lead ECG — I did not perceive there to be any significant change between these 2 tracings in Figure-3.

13 Minutes Later ...

Figure-4: Holter-B — recorded just 13 minutes later (at 11:29 pm) while the patient was still sleeping.

Subsequent Recordings during Sleep ...

Figure-5: Holter-C — recorded ~2 hours after Holter-B (at 1:23 am). The ST elevation that began in Holter-B has now progressed — with development of prominent Q waves in leads V2,V3,V4 — and extensive hyperacute ST-T waves. The patient still asleep ...  

Figure-6: Holter-D — recorded at 7:30 am the next morning.

Figure-7: A closer look at Holter-D — in which I've labeled regular-occurring P waves that are unrelated and "march through" neighboring QRS complexes ==> complete AV Block. These RED arrow P waves are not from the SA Node (as these P waves are no longer upright in lead aVF). The vertical RED line marks the end point of the now widened QRS complex in these 6 simultaneously-recorded leads. The ST segment begins to the right of this vertical RED line, and still shows obvious ST elevation in the lateral chest leads.

Figure-8: 10 minutes after Holter D — We now see a markedly widened agonal rhythm without atrial activity.

Figure-9: 12 minutes later a flat line is seen ...

Editorial Comment:

Today's case is difficult. This elderly woman who lived alone — died at home in her sleep. These Holter tracings were only retrieved afterward.

• Presumably — the initial ECG in Figure-2 did represent recent LAD occlusion and infarction in the form of a "silent" MI in this elderly woman who presented with minimal "CP-equivalent" symptoms ( = some dizzyness and fatigue) — but who otherwise looked good and wanted to go home.
• Presumably, the reason this patient's initial ECG did not show acute ST elevation — is that some time after LAD occlusion, there was spontaneous reperfusion of her MI, with resolution of what must have been ST elevation several hours earlier. The RED arrows in leads III; V1,V2,V3 — as well as the Blue question marks in her initial ECG (in Figure-2) clearly represented reperfusion T waves.
• 
  
• I have "been there". As a family medicine Attending and faculty physician for 30 years — we would periodically see elderly patients present a day or more after they had symptoms, with an ECG similar to that shown in Figure-2. While hospitalization for a day or two to ensure nothing active is still ongoing would be ideal in such cases (and depending on case specifics — serial tracings, Troponins and in some instances cardiac catheterization would all ideally be done) — that is not always the path chosen by these older patients who decide (with full informed consent) that they simply want to return home.

I have also "been there" in the eerie situation of interpreting a Holter monitor recording on a patient admitted to the hospital and seemingly doing well on a telemetry-monitored floor — while all of a sudden as I'm interpreting the Holter — I see sudden slowing of the heart rate on sequential rhythm strips that reveal progressive evolution to VFib and cardiac arrest.

• At that point — I ran upstairs to the patient's room, only to find a full complement of health care providers in the midst of what turned out to be an unsuccessful resuscitation effort on the patient whose Holter I had been in the middle of interpreting ...
• These are tough cases. We go back and ask ourselves what could have been done differently to avoid the patient's unexpected demise? We don't necessarily come up with answers — but the soul-searching retrospection is an essential component of our need to draw meaning from these tragic occurrences that we painfully hope to learn from.
• P.S.: I found the literature sadly lacking in examples of Holters serendipitously recorded during the evolution of an acute cardiac event. While realistically impossible to avoid all future episodes of this kind — We need to learn from such cases. (See Watanabe et al — Heart Rhythm 8:18-25, 2014 and Nikolic et al — Circulation 66(1):218-225, 1982).

Final "Take-Aways" ...

• Be aware of the multiple subtle appearances that an ECG may have following recent infarction. Look for the reperfusion T waves of spontaneous reperfusion. Depending on when during the course of evolution the ECG is recorded — there may be "pseudo-normalization" — in which an ECG captured in between the phase of resolving ST elevation on the way to developing reperfusion T waves — the ECG may look relatively "normal" (See ECG Blog #467).
• The patient's symptoms may be subtle (as in the Audio Pearl on "Silent MI" in ECG Blog #228). Be especially attuned for subtle symptoms that may reflect recent infarction in older patients.
• Correlate the timing of the presence and relative severity of patient symptoms to the timing of each ECG that is recorded. Learning that symptoms may have decreased several hours later (at the time the ECG you are looking at was recorded) — clues us in to the need to appreciate subtle findings on that ECG that may be important.
• Realize that no matter how diligent we may be — unexpected events as occurred in today's case sometimes happen ...

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Acknowledgment: My appreciation to Passang Jinpa (from Guayaquil, Ecuador) — for allowing me to use this case and this tracing.

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pful ...