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Clinical case studies

The bizarre atrioventricular (AV) delay

In this first of his Fun With ECG series, our MD Assoc Prof Harry Mond looks at this bizarre atrioventricular (AV) delay. Look closely at the ECG. The AV delay timings don’t make sense. The AV delay for atrial sensing/ventricular pacing (As Vp) is always...

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Clinical case studies

Interpreting the Holter monitor rate histogram

In this rare case, we see two very unusual and critical factors that together lead to atrial oversensing and “apparent” violation of the lower rate limit; a very narrow zone of open atrial sensing and far-field R wave sensing. While the first time MD Assoc...

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Clinical case studies

Non-physiologic atrial pacing

First thoughts on this Holter tracing was artefact, but the native rhythm showed a regular pattern of irregularity! Taking a close look at overnight tracings when the rhythm would be slow and the “artefact” less likely, revealed what was really going on. In this case...

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Medical Papers

The electrocardiographic interpretation of pacemaker algorithms enabling...

Cardiac pacing from the apex of the right ventricle has been shown to result in left ventricular dysfunction, atrial fibrillation and increased mortality. To counter this, one of the strategies developed, is to avoid ventricular pacing when not necessary, using programmable algorithms to minimize ventricular...

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Clinical case studies

Vagal hypertonia in 44-year male

The Holter monitor tracings of a 44-year old male caused a lot of excitement at CardioScan this week. With 12 bradycardia episodes overnight, it was initially considered Wenckebach AV block. While clinically, rather than visually, correct, it nevertheless, did not fulfil the footprints of Wenckebach...

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Clinical case studies

Mode switching: Fast and slow pacing

Seen for the first time, the pattern in this 24hr histogram gives instantly recognisable clues about what is happening, even without looking at the tracings. Normally, we see a diurnal pattern of rate changes during the day with lower rates at night, but rarely a...

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Clinical case studies

Is this rate adaptive pacing?

Handed this ECG, our Medical Director Assoc Prof Harry Mond was asked if it was an example of a rate adaptive pacing, which uses changes in transthoracic impedance to increase the pacemaker rate in response to physiologic demand. It was not a paced rhythm, however,...

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Clinical case studies

What’s in a name?

Sinus arrhythmia is unusual in a 63-yr-old but we were asked to amend a ‘normal’ result to reflect this diagnosis. With classical examples of the pattern in under 30s and showing how NOT to confuse it with atrial ectopy, Assoc Prod Harry Mond shows how...

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Clinical case studies

Nocturnal pauses and bundle branch block –...

Showing a number of 2.8 second nocturnal pauses and bundle branch block, this latest case begs the question: is this high degree AV block and does the patient need a pacemaker? Using 11 difference traces, Assoc Prof Harry Mond delves into the topic of Wenckebach...

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