Imaging in cardiology A.C.P. Wiesfeld, I.C. van Gelder, G.J. van Mill, E.S. Tan, H.J.G.M. Crijns, D.J. van Veldhuisen
A. PMation
B. Ps-i
before ablation showed only signs of right atrial bypertropby Electrocardiogram The elctrocardiogram after ablation sowed a sinus ryhm with vertical axis; tigbtatral ypertnropby and right ventricularconduction delay. Such an electrocardiogram can befound in patientswith Ebstin's disease. Figure 1. Electrocardiogram (25
(25 mmls, 10 mm/mV)
mins, 10 mm/mV)
(B) after ablat
(A)
of Mahaim fibre.
From normal to Mahalm to Ebstein
e
ocardogram
A 20-year-old man with Ebstein's disease had been suffering from attacks of palpitations caused by tachycardia for two years. The attacks occurred twice monthly with a duration often minutes to two hours.
A.C.P. Whfeld. I.C. van Gelder. E.S. Tan. D.J. van Voldhulsen. University Hospital Groningen, Thoraxcenter, Department of Cardiology, PO Box 30001, 9700 RB Groningen. GJ. van Mil. University Hospital N,jmegen, Department of Cardiology, PO Box 9101, 6500 NB Nyjmegen. H.J.G.M. Crjns. University Hospital Maastricht, Department of Cardiology, PO Box 5800, 6202 AZ Maastricht Address for correspondence: A.C.P. Wiesfeld. E-mail: [email protected]
272
Echocardiographically the right ventricle was enlarged in comparison with the normal left ventricle. The function of both ventricles was normal. A severe tricuspid regurgitation was present due to apical insertion of the septal tricuspidal cusp. The electrocardiogram showed signs ofright atrial hypertrophy but was otherwise normal despite the presence of Ebstein's disease (figure LA). An electrocardiogram of the tachycardia showed broad QRS complexes and a 'left bundle branch block'-like morphology with a northwest axis (figure 2). During electrophysiological investigations, the clinical tachycardia was induced which was identical to figure 2, and fulfilled the criteria for antidromic tachycardia using a Mahaim connection. Mapping revealed a potential on the tricuspid annulus which was ablated successfully. The electrocardiogram after the ablation changed dramatically and became a right bundle branch block with undetermined axis and right atrial hypertrophy, which was compatible with the underlying heart disease (figure 1B).
Netherlands Hear Journal, Volume 11, Number 6, June 2003
Imaging in cardiology
l M RSI!!!! y mi'F40 E E m l~~~~~~~~~~~~M
IV,aPav isreeni d1 Twav TheR :intrvl.islongerthan1d-ie R U.inevlTer isnoatrivnclariscito 11 rtrqgrad or| 1V1aWnteogad atr enrclar conducto is posbe Thr i1s ncoorat QSmrpogyaddeR urtn .:a.......ativatio ._..tria _. isE shorerhn10m in hrcria las A spaetriua tacyai wtith aberncodtioorvniclar tahycri is still possible. T mopolg e criea shul be aplid th sml- ini tIalRin V1 an V21 sggests a ta -rIausin th His Puki syte
antero,gradely. However, on thye basis of the slur in the ne,gative initial part of II, III, aVF a Mahaim fibre with antidromic tachycardia should be considered.
Mahaim fibres are nodal-ventricular or atriofascicular bypass tracts. The latter are described in combination with arrhythmias. The atriofascicular bypass tracts start in the right atrial anterolateral wall and insert in the right ventricular apex near the right bundle or connect directly to the right bundle. Mahaim fibres only conduct anterogradely and contain nodal tissue. Hence, they show decremental conduction, i.e. decrease of conduction during increase ofheart rate. The Mahaim fibres are rare and their incidence is less than 3% of all bypass tracts. The incidence of Mahaim fibres is higher in patients with Ebstein's disease. Moreover, 10% ofthe patients with a Mahaim fibre have more than one bypass tract, especially in the setting of Ebstein's disease. In patients with a Mahaim fibre, the electrocardiogram without tachycardia does not show preexcitation but they do have tachycardias with preexcitation. The electrocardiographic characteristics of the antidromic tachycardias are left bundle branch block morphology, QRS axis is superior or 0-75 degrees, a long atrioventricular delay (due to long conductions times over the Mahaim fibre) and short ventriculo-atrial interval: RP
A. PMation
B. Ps-i
before ablation showed only signs of right atrial bypertropby Electrocardiogram The elctrocardiogram after ablation sowed a sinus ryhm with vertical axis; tigbtatral ypertnropby and right ventricularconduction delay. Such an electrocardiogram can befound in patientswith Ebstin's disease. Figure 1. Electrocardiogram (25
(25 mmls, 10 mm/mV)
mins, 10 mm/mV)
(B) after ablat
(A)
of Mahaim fibre.
From normal to Mahalm to Ebstein
e
ocardogram
A 20-year-old man with Ebstein's disease had been suffering from attacks of palpitations caused by tachycardia for two years. The attacks occurred twice monthly with a duration often minutes to two hours.
A.C.P. Whfeld. I.C. van Gelder. E.S. Tan. D.J. van Voldhulsen. University Hospital Groningen, Thoraxcenter, Department of Cardiology, PO Box 30001, 9700 RB Groningen. GJ. van Mil. University Hospital N,jmegen, Department of Cardiology, PO Box 9101, 6500 NB Nyjmegen. H.J.G.M. Crjns. University Hospital Maastricht, Department of Cardiology, PO Box 5800, 6202 AZ Maastricht Address for correspondence: A.C.P. Wiesfeld. E-mail: [email protected]
272
Echocardiographically the right ventricle was enlarged in comparison with the normal left ventricle. The function of both ventricles was normal. A severe tricuspid regurgitation was present due to apical insertion of the septal tricuspidal cusp. The electrocardiogram showed signs ofright atrial hypertrophy but was otherwise normal despite the presence of Ebstein's disease (figure LA). An electrocardiogram of the tachycardia showed broad QRS complexes and a 'left bundle branch block'-like morphology with a northwest axis (figure 2). During electrophysiological investigations, the clinical tachycardia was induced which was identical to figure 2, and fulfilled the criteria for antidromic tachycardia using a Mahaim connection. Mapping revealed a potential on the tricuspid annulus which was ablated successfully. The electrocardiogram after the ablation changed dramatically and became a right bundle branch block with undetermined axis and right atrial hypertrophy, which was compatible with the underlying heart disease (figure 1B).
Netherlands Hear Journal, Volume 11, Number 6, June 2003
Imaging in cardiology
l M RSI!!!! y mi'F40 E E m l~~~~~~~~~~~~M
IV,aPav isreeni d1 Twav TheR :intrvl.islongerthan1d-ie R U.inevlTer isnoatrivnclariscito 11 rtrqgrad or| 1V1aWnteogad atr enrclar conducto is posbe Thr i1s ncoorat QSmrpogyaddeR urtn .:a.......ativatio ._..tria _. isE shorerhn10m in hrcria las A spaetriua tacyai wtith aberncodtioorvniclar tahycri is still possible. T mopolg e criea shul be aplid th sml- ini tIalRin V1 an V21 sggests a ta -rIausin th His Puki syte
antero,gradely. However, on thye basis of the slur in the ne,gative initial part of II, III, aVF a Mahaim fibre with antidromic tachycardia should be considered.
Mahaim fibres are nodal-ventricular or atriofascicular bypass tracts. The latter are described in combination with arrhythmias. The atriofascicular bypass tracts start in the right atrial anterolateral wall and insert in the right ventricular apex near the right bundle or connect directly to the right bundle. Mahaim fibres only conduct anterogradely and contain nodal tissue. Hence, they show decremental conduction, i.e. decrease of conduction during increase ofheart rate. The Mahaim fibres are rare and their incidence is less than 3% of all bypass tracts. The incidence of Mahaim fibres is higher in patients with Ebstein's disease. Moreover, 10% ofthe patients with a Mahaim fibre have more than one bypass tract, especially in the setting of Ebstein's disease. In patients with a Mahaim fibre, the electrocardiogram without tachycardia does not show preexcitation but they do have tachycardias with preexcitation. The electrocardiographic characteristics of the antidromic tachycardias are left bundle branch block morphology, QRS axis is superior or 0-75 degrees, a long atrioventricular delay (due to long conductions times over the Mahaim fibre) and short ventriculo-atrial interval: RP
