It's not what you think it is - Europe PMC

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It's not what you think it is. A.A.M. Wilde, T.A. Simmers. Figure 1. A20-year-old male is having palpitations. They occurwithout a specific trigger, although ...

RHYTHM PUZZLE

It's not what you think

it

is

A.A.M. Wilde, T.A. Simmers

Figure 1.

A 20-year-old male is having palpitations. They occur without a specific trigger, although episodes are sometimes related to emotion or exercise. Duration is between two minutes and one hour. He does not

A.A.M. Wilde T.A. Simmer Department of Cardiology, AMC Amsterdam

Correspondence to: A.A.M. Wilde Department of Cardiology, Amsterdam Medical Centre, PO Box 22660, 1100 DD Amsterdam E-mail: [email protected]

244

feel well during an attack, but has never fainted. Physical examination reveals no abnormalities nor does laboratory investigation or echocardiography. His baseline ECG is normal (not shown). He was asked to come to the emergency room if an episode lasted long enough, which he did (figure 1). Upon presentation during an attack the ECG recorded a narrow-complex tachycardia with an RR interval of 280 msec (214 beats/min). There is a slight rightward deviation ofthe electrical axis. ST morphology is normal and no P wave can be identified. The differential diagnosis is 1. atrioventricular nodal reentry tachycardia (AVNRT), 2. orthodromic tachycardia with a concealed bypass (AVRT) and 3. atrial tachyNetherlands Heart Journal, Volume 13, Number 6, June 2005

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Figure 2. cardia. Adenosine was administered and the ECG presented in figure 2 was recorded. U

Answer

You will find the answer on page 249.

What is your diagnosis and what would yourfurther treatment be?

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Netheriands Heart Journal, Volume 13, Number 6, June 2005

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LETTER TO THE EDITOR

Piercing the left lung with a pacemaker lead, an uncommon complication To the editor

Hassan, Widdershoven, Molenaar and Wmter (Neth HeartJ2004;12:537-9) reported on a patient experiencing an uncommon complication in pacemaker insertion, which raises two comments. Cutdown of the cephalic vein is a very safe procedure and the cephalic vein is almost always present. If the anatomical landmarks, the pectoral and deltoid muscles and the davicle are recognised, it is not difficult to find the cephalic vein in Mohrenheim's groove, two or three centimetres caudally from the davide. Whether a patient is obese or not, the landmarks are always there. In my opinion there is no reason to consider this method of dissection obsolete, as Hassan, et al. do in their artide, by saying that the procedure was discontinued after the late 1960s. I make a plea for cutdown ofthe cephalic vein as the method of choice for insertion of pacemaker leads, because it is a safe method and applicable in almost every patient. The second comment is in relation to the first. If the above-mentioned anatomical landmarks are recognised during subclavian vein puncture, entering the thorax through an intercostal space can be avoided. By palpation

through the wound the clavicle can be identified and direct puncture in the extrathoracic subclavian vein is easily accomplished. Furthermore, the position of the needle, directly after reaching the subclavian vein and after introducing the guide wire, can be confirmed by fluoroscopy. By doing so an abnormal position of the wire can lead to recognition of a faulty puncture before a lead is actually inserted. Therefore this complication is not only uncommon, but also totally avoidable. The cause is insufficient care in recognising important anatomical landmarks during a surgical intervention. It must be realised that pacemaker insertion is a surgical procedure and that surgical knowledge and surgical skills are mandatory. This case report makes me think of one of the rules from Samuel MD Shem's book 'The House ofGod': With a strong arm and a 14 G needle one can reach any body cavity. U T. W. Waterbolk cardiothoracic surgeon Thorax Centre, University Medical Centre Groningen

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Answer to the rhythm puzzle on page 244 Figure 2 shows a narrow complex rhythm, with an RR interval of 560 msec, i.e. a rate exactly half of that before adenosine. P waves are now clearly discemable with an axis compatible with sinus rhythm. This suggests either sinus rhythm, or a supraventricular tachycardia with 2:1 block in the AV node caused by adenosine and comparable P wave morphology. AVRT can be excluded as a 1:1 relation between atrium and ventricle is required. AVNRT with 2:1 block to the ventricle is also highly unlikely because of the morphology ofthe P waves, which in that case would be negative in the inferior leads due to retrograde activation ofthe atrium. The only remaining alternative is atrial tachycardia from an area in the vicinity of the sinus node. Indeed, on closer examination there is evidence of a second P wave partly hidden in the terminal part of the T wave in lead V1.

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Nethlaands Heart Journal, Volume 13, Number 6, June 2005

Shortly after this ECG was obtained the tachycardia (figure 1) resumed. A higher dose of adenosine terminated the tachycardia and sinus rhythm (60 beats/min) appeared. Atrial tachycardias occasionally respond to adenosine. In those cases the underlying electrophysiological mechanism is triggered activity based on delayed afterdepolarisations."2 These tachycardias usually respond well to 5-blockade or verapamil, and are generally amenable to catheter ablation. U Refrences 1 2

Markowitz SM, Stein KM, Mittal S, et al. Differential effects of adenosine on focal and macroreentrant atrial tachycardia. J Cardiovasc Ekctrophysiol 1999;10:489-502. Lerman BB, Stein KM, Markowitz SM. Adenosine sensitive ventricular tachycardia: a conceptual approach. J Cardiovasc Ekctrophysiol 196;7:559-69.

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