Figure 1 showed his ECG on admission. What is the diagnosis?

The EKG showed a regular wide-complex tachycardia at a ventricular rate of 130/min. With the history provided, atrial flutter with 2:1 block with existing LBBB was the most likely clinical diagnosis. Classical saw-toothed flutter waves would be difficult to find with existing LBBB. Without any clinical information, the differential diagnosis of this ECG tracing would include ventricular tachycardia and tachycardia with pacing beats.

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Figure 2 showed his ECG after an IV bolus injection. What is the diagnosis? What could be the drug injected?

The ECG showed atrial fibrillation with LBBB. A bolus of ATP 20mg IVI was given. This is a short-acting drug which slows down AV conduction, which may reveal the mechanism of underlying arrhythmia. With slowing down of AV conduction, underlying flutter fibrillation was seen. As the effect of ATP is very short lasting, this is a very safe and useful drug to aid in the bedside diagnosis as well as treatment of many arrhythmias. However, it is contraindicated in patients with asthma or COPD.

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His arrhythmia soon recurred a few minutes after the IV injection was over. Figure 3 showed his ECG after a therapeutic procedure. What is the final diagnosis? What could be the procedure done?

The procedure done was 50J DC shock, which successfully aborted the atrial flutter to atrial fibrillation. Atrial flutter typically required very low electric energy for cardioversion (usually only 25- 50J).

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What is this investigation?

Patch testing.

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What is the indication for this investigation?

A patch test is performed to confirm a clinical suspicion of allergic contact dermatitis (ACD) and differentiate it from irritant contact dermatitis. ACD is a type IV or cell-mediated immune disease caused by an allergic reaction to material in contact with the skin.

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How is this investigation performed?

The test materials are applied to the upper back under individual aluminium discs, affixed to a strip of paper tape. The test materials are removed at 48 hours and test area inspected. As the reaction is delayed, re-inspection at 96 hours is required. A positive reaction shows spreading erythema, edema, and closely set vesicles that persist or appear after removal of the patch.

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What are the substances commonly tested?

There are many possible allergens. Commonly tested substances consist of metal (e.g. nickel, cobalt); medicament (e.g. benzocaine, neomycin); rubber (e.g. Carba mix, Thiuram mix, Black rubber mix); fragrances; preservative; and others (e.g. p-Phenylenediamine which is present in hair dye).

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Are there any possible complications for this investigation?

Flare-ups of dermatitis may occur in some patients. Strong patch test reactions may induce “angry back syndrome” in which other test sites also become positive.

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