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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 28, No 4, July/August 2017

AFRICA

257

Reviewing the causes of electrocardiographic pauses

Charle Viljoen, Robert Smith, Ashley Chin

Abstract

The electrocardiographic term ‘pause’ refers to the prolonged

R-R interval that represents the interruption in ventricular

depolarisation. This article presents a case of sinus node

dysfunction and provides a diagnostic approach to pauses on

the ECG.

Keywords:

ECG, sinus node dysfunction, SA exit block, sinus

arrest

Cardiovasc J Afr

2017;

28

: 257–260

www.cvja.co.za

DOI: 10.5830/CVJA-2017-041

A 48-year-old man was referred to the Cardiac Clinic at Groote

Schuur Hospital for evaluation of suspected symptomatic aortic

stenosis. He had a medical history of hypertension, which was

well controlled on amlodipine 10 mg and atenolol 50 mg once

daily.

He had presented with three episodes of syncope in the

three months prior to assessment. The syncope was not related

to exertion, standing or other specific situations and occurred

without any prodrome. He was not troubled by any dyspnoea,

and he denied chest pain and any palpitations.

Examination excluded severe aortic stenosis. He had regular,

good volume pulses, a normal jugular venous pressure and

an undisplaced apex beat with normal character. There was

a soft ejection systolic murmur, best heard at the lower left

sternal border with no radiation. The lung bases were clear.

An electrocardiogram (ECG) and echocardiography were

performed. Echocardiography showed a normal aortic valve

with no evidence of aortic stenosis.

TheECG(Fig. 1) showed an irregular rhythmwith intermittent

pauses. There were no premature complexes preceding the

pauses. However, during each of the pauses, there were no P

waves at the expected time interval. The R-R interval during

the pause was twice the R-R interval before and after the pause.

Division of Cardiology, Groote Schuur Hospital and the

University of Cape Town, South Africa

Charle Viljoen, MB ChB, MMed, FCP (SA),

charleviljoen@gmail.com

Ashley Chin, MB ChB, FCP (SA), MPhil

Department of Medicine, Groote Schuur Hospital and the

University of Cape Town, South Africa

Robert Smith, MB ChB

ECG Series

Fig. 1.

The 12-lead ECG is in keeping with sino-atrial exit block.