Download Paroxysmal Supraventricular Tachycardia with QRS Duration

Case Report
Acta Cardiol Sin 2013;29:192-195
Paroxysmal Supraventricular Tachycardia with QRS
Duration Alternans, Electrical Alternans, and Pulsus
Alternans but without Cycle Length Alternans
Wei-Ta Chen,1 Ho-Shun Cheng,1 Jen-Hung Huang1,2 and Ming-Hsiung Hsieh1,2
We reported a 60-year-old male patient who had a paroxysmal supraventricular tachycardia with QRS duration
alternans (alternation between narrow QRS and wide QRS beats) and electrical alternans, but without any cycle
length alternans. In the laboratory, slow-fast atrioventricular nodal reentrant tachycardia was easily induced by an
atrial extrastimulus, and the arterial pressure recordings displayed a simultaneous pulsus alternans during
tachycardia. The patient also underwent coronary angiography which revealed a total occlusion of the left anterior
descending artery. In this report, we have proposed that the QRS duration alternans, electrical alternans and
pulsus alternans during the paroxysmal supraventricular tachycardia may have been due to the prolongation of the
effective refractory period of the right bundle branch, caused by myocardial ischemia.
Key Words:
Electrical alternans · Myocardial ischemia · Supraventricular tachycardia
INTRODUCTION
ternans is defined as alternation of the amplitude of
QRS complex. The most common cause for electrical
alternans is pericardial effusion.5 The functional swings
of the heart make the amplitude of QRS complex change.
However, myocardial ischemia would cause both phenomena.6
We herein presented a case of PSVT with QRS duration alternans, but without cycle length alternans. The
findings of pulsus alternans and electrical alternans
were noted simultaneously, so myocardial ischemia was
suspected as the cause of the above findings. Coronary
angiography also confirmed our suspicion. To our knowledge, this is the first case report for such conditions,
and the possible etiology is myocardial ischemia.
QRS duration alternans is a sign of QRS duration oscillation beat by beat. It is a rare clinical condition, and
frequently associated with paroxysmal supraventricular
tachycardia (PSVT). The nature of the definitive underlying mechanism is still unclear, but it was most often
noted during atrioventricular reciprocating tachycardia
with two distinct antegrade conduction pathways. 1,2
Therefore, the QRS alternans during PSVT is commonly
associated with cycle length alternans. 1-3 Clinically,
pulsus alternans is most often noted in the condition of
left ventricular systolic failure.4 In addition, electrical al-
Received: April 12, 2012
Accepted: July 13, 2012
1
Division of Cardiovascular Medicine, Department of Internal Medicine,
Wan-Fang Hospital, Taipei Medical University; 2Department of Internal
Medicine, School of Medicine, College of Medicine, Taipei Medical
University, Taipei, Taiwan.
Address correspondence and reprint requests to: Dr. Ming-Hsiung
Hsieh, Division of Cardiovascular Medicine, Taipei Wan-Fang Hospital,
No. 111, Section 3, Hsin-Lung Road, Taipei, Taiwan. Tel: 886-22930-7930 ext. 2818; Fax: 886-2-2933-9378; E-mail: td7279@ms25.
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Acta Cardiol Sin 2013;29:192-195
CASE REPORT
A 60-year-old man was sent to the emergency department twice in 10 days due to a sudden onset of palpitations and chest tightness. His physical examination
revealed a heart rate of 140 bpm and the 12-lead ECG
(Figure 1A) showed a paroxysmal supraventricular
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PSVT with QRS Alternans
revealed a total occlusion of the left anterior descending (LAD) artery (arrowhead) (Figure 1B). In the laboratory, slow-fast atrioventricular nodal reentrant tachycardia (AVNRT) was easily induced by atrial extrastimulus
(Figure 2A). The QRS duration alternans and electrical
alternans persisted during each tachycardia episode.
The arterial pressure recordings displayed a simultaneous pulsus alternans during the tachycardia (arrow),
and the ECG exhibited a wide QRS beat (when bundle
branch block occurred) after the occurrence of a lower
arterial pressure (Figure 2A). After delivering a premature ventricular beat, the QRS duration alternans and
pulsus alternans persisted, but the ECG exhibited a wide
tachycardia (PSVT) with QRS duration alternans (alternation between narrow QRS and wide QRS beats) and
electrical alternans, but without any cycle length alternans. The symptoms and heart rate resolved after an
intravenous bolus of 6 mg of adenosine. The patient was
referred to our clinic for further evaluation and management. Later echocardiographic imaging showed no evidence of hypertrophic cardiomyopathy. The patient performed a treadmill exercise test for a duration of 6
minutes, which revealed ST depression of more than 1
mm in the inferior leads. He then underwent coronary
angiography and an electrophysiologic (EP) study plus
catheter ablation. Review of the coronary angiography
A
B
Figure 1. (A) A 12-lead ECG revealing paroxysmal supraventricular tachycardia with QRS duration alternans (alternation between narrow QRS and
wide QRS beats) and electrical alternans, but without any cycle length alternans. All the wide QRS beats had right bundle branch block morphology
except for one ventricular premature beat. (B) A fluoroscopic view of the coronary arteries revealed a chronic total occlusion of the left anterior descending artery (arrowhead) with collateral circulation from the branches.
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Acta Cardiol Sin 2013;29:192-195
Wei-Ta Chen et al.
right bundle branch, and could have been responsible
for the generation of the QRS duration alternans during
the PSVT. As shown in Figure 2B, a weak pulse (low
blood pressure) is caused by the VPB because of inadequate venous return. According to the Frank-Starling
law, the following beat (after VPB) with a longer ventricular filling time should be a strong pulse (high blood
QRS beat after the occurrence of a higher arterial pressure (Figure 2B). Successful slow AV node modification
was done without any complications. There was normal
pulse (no pulse alternans) during sinus rhythm before
and after ablation. In addition, successful percutaneous
coronary intervention of the totally occluded lesion of
the LAD artery was performed using a drug-eluting stent
during the following admission.
DISCUSSION
Mechanical (pulsus) alternans and electrical alternans are both associated with myocardial ischemia and
are not an uncommon phenomenon during PSVT. 6-8
However, QRS duration alternans is a rare condition
during PSVT, and is frequently associated with a cycle
length alternans. 9,10 Interestingly, the QRS duration
alternans in our case occurred during all PSVT episodes,
but without any cycle length alternans. Apparently, the
QRS duration alternans was not related to the cycle
length alternans, which completely differed from the
previous reports. It is amazing that the QRS alternans
persisted simultaneous with the pulsus alternans and
electrical alternans. A narrow QRS beat was noted after
the occurrence of a higher arterial pressure (Figure 2A).
We originally proposed that the mechanoelectric feedback (a higher pressure resulted in a shorter action potential duration and effective refractory period) modulated the regional electrophysiologic characteristics in
the right bundle branch, and may have been responsible
for the generation of the QRS duration alternans.7 However, after delivering a ventricular premature beat, the
relationship between the QRS duration alternans and
pulsus alternans changed: a wide QRS beat was found
after the occurrence of a higher arterial pressure. Therefore, the mechanoelectric feedback could not explain
the phenomenon. After reviewing the report from the
treadmill exercise test, we found that the right bundle
branch block was rate-dependent. It happened when
the heart rate became faster than 120 beats per minute.
In addition, the blood supply to the right bundle branch
was from the septal branch of the LAD artery which was
completely blocked in this case. Maybe an anatomic
cause (myocardial ischemia) could have resulted in the
prolongation of the effective refractory period of the
Acta Cardiol Sin 2013;29:192-195
A
B
Figure 2. The intracardiac recordings from top to bottom are surface
ECG leads II, aVF and V1, intracardiac recordings from the high right
atrium (HRA), distal His (HIS-D) and right ventricular apex (RVA) and an
arterial pressure recording (PRES) from the femoral artery. (A) The recording revealed the initiation of an atrioventricular nodal reentrant
tachycardia after an atrial extrastimulus (S2). The QRS duration alternans persisted during the tachycardia and the arterial pressure recording displayed simultaneously, exhibited pulsus alternans (125 and
110 mmHg alternatively). The narrow QRS beat is followed by a higher
arterial pressure and the wide QRS beat (with right bundle branch
block) is followed by a lower arterial pressure (arrows). (B) We delivered
a ventricular premature beat (VPB) during the supraventricular tachycardia. The QRS duration alternans and pulsus alternans persisted after
the VPB, however, the relationship of the two alternans changed: the
narrow QRS beat is followed by a lower arterial pressure and the wide
QRS beat (with right bundle branch block) is followed by a higher arterial pressure (arrows).
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PSVT with QRS Alternans
3. Lam HD, Stroobandt R, Knight BP. Supraventricular tachycardia
with alternating cycle length: what is the mechanism? J Cardiovasc Electrophysiol 2001;12:1329-30.
4. Gleason WL, Braunwald E. Studies on Starling’s law of the heart.
VI. Relationships between left ventricular end-diastolic volume
and stroke volume in man with observations on the mechanism
of pulsus alternans. Circulation 1962;25:841-8.
5. Rinkenberger RL, Polumbo RA, Bolton MR, Dunn M. Mechanism
of electrical alternans in patients with pericardial effusion.
Cathet Cardiovasc Diagn 1978;4:63-70.
6. Surawicz B, Fisch C. Cardiac alternans: diverse mechanisms and
clinical manifestations. J Am Coll Cardiol 1992;20:483-99.
7. Murphy CF, Lab MJ, Horner SM, et al. Regional electromechanical alternans in anesthetized pig hearts: modulation by
mechanoelectric feedback. Am J Physiol 1994;267:H1726-35.
8. Morady F. Significance of QRS alternans during narrow QRS
tachycardias. PACE 1991;14:2193-8.
9. Maury P, Raczka F, Piot C, Davy JM. QRS and cycle length alternans during paroxysmal supraventricular tachycardia: what is
the mechanism? J Cardiovasc Electrophysiol 2002;13:92-3.
10. Wongcharoen W, Tai CT, Lin YJ, et al. Alternate morphologies of
QRS complex during a tachycardia: what is the mechanism? J
Cardiovasc Electrophysiol 2006;17:1255-6.
pressure). In addition, the VPB depolarized the right
bundle earlier and resulted in the following narrow QRS
beat. Therefore, the relationship between two alternans
changed. Finally, the patient underwent follow-up treadmill exercise test several months later for evaluating recurrent angina, and rate related bundle branch block
was still found.
In conclusion, we reported a case with QRS duration
alternans, electrical alternans and pulsus alternans during PSVT episodes but without cycle length alternans.
Those alternans may have been due to the total occlusion of the LAD artery.
REFERENCES
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tachycardia with QRS voltage and cycle length alternation and
aberrant conduction due to two distinct antegrade slow pathways. Europace 2006;8:134-7.
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