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Intermittent concealed atrial conduction demonstrated through intracavitary leads
J. ELECTROCARDIOLOGY 11 (1), 1978, 85-86
Intermittent Concealed Atrial Conduction Demonstrated Through Intracavitary Leads BY S. COTOI, M.D., C. GEORGESCU, M.D. AND D. MOLDOVAN, M.D.
recorded on the ECG. In order to analyse the atrial activity more completely, carotid sinus massage (CSM) was used. During CSM it was possible to record on the ECG a transition from complexes with normal P waves to complexes without P waves, but normal atrial activity, as demonstrated by i n t r a c a v i t a r y electrogram and right atrial monophasic action potential, was recorded simultaneously (Fig. 2). In Fig. 3, the transition from complexes without P waves to complexes with P waves was recorded, with unchanged atrial activity on the intracavitary recordings.
SUMMARY An intermittent vanishing of the P wave from a s t a n d a r d electrocardiogram (ECG) while normal atrial activity was recorded on intraeavitary leads was observed in a 58 year old man. This i n t e r m i t t e n t c o n c e a l e d atrial conduction is d i s c u s s e d . The absence of the P wave from the electrocardiogram has been reported in m a n y situations. 1~ An uncommon electrocardiographic finding, consisting of the unexpected, brief disappearance of the P wave, was observed, although intraatrial activity recorded on intracavitary electrogram was unchanged. We feel t h a t t h i s r a r e s i t u a t i o n m e r i t s publication.
DISCUSSION The persistence of conduction over the specialized a t r i a l t r a c t s in conditions of h y p e r k a l e m i a has been demonstrated. The impulse is transmitted to the ventricles without P wave inscription. This phenomenon is called sino-ventricular conduction. 1-4 The lack of P wave inscription may also occur in a t r i a l s t a n d s t i l l , in m i d a t r i o ventricular junctional r h y t h m , in sinoatrial block, and when there has been extensive destruction of atrial myocardium in advanced rheumatic h e a r t disease. 3,~9 It is difficult to explain our patient's normal atrial activity, demonstrated on intracavitary recordings but hidden from time to time on the ECG. Taking into account sinoventricular conduction a l o n g w i t h n o r m a l p o t a s s i u m levels, we may consider t h a t our recording was obtained only from a specialized conduction pathway. In our opinion the other situations in which the P wave is not recorded on the ECG ought to be discarded. We consider this case to be interesting because of the unexpected vanishing of the P wave from the ECG while normal atrial activity is recorded on intracavitary recordings. It is difficult to explain this situation, which we have called " i n t e r m i t t e n t concealed atrial conduction."
CASE REPORT A 58 year old man with coronary heart disease was hospitalized because of signs of congestive h e a r t failure. His daily medications included digoxin (0.5 mg) and furosemide (80 mg). Physical examination revealed no unusual signs, the laboratory data were within normal ranges (no hyperkalemia or hyponatremia), and there were no signs of digitalis toxicity. However, from time to time and for short periods, a lack of P wave was observed in all the ECG leads, but without changes in the ventricular rate (Fig. 1). Using a suction bipolar electrode catheter, 1~ we recorded monophasic action potential from the right atrium, finding normal atrial activity even when the P wave was not From the F i r s t Medical Clinic, Tg.Mures, Romania. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. w solely to indicate this fact. Reprint requests to: S. Cotoi, M.D., Clinica I-a Medicala, 4300 Tg. Mures, Romania.
25 ~ s e :
Fig. 1. Standard ECG leads III and aVF, recorded simultaneously. The first four complexes before the ventricular premature beat are without P wave, and the last four ones with evident P wave. Paper speed is 25 mm/sec.
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Fig. 2. Simultaneous recording of right atrial monophasic action potential (RA MAP), intracavitary ECG (IC), and leads I, II and III during carotid sinus massage (CSM). The first complex is a normal one, then during CSM there are no P waves, but normal atrial activity on the intracavitary recordings. The last two complexes, recorded later, are with normal P waves. Paper speed is 50 mm/sec.
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Fig. 3. Simultaneous recording of right atrial monophasic action potential (RA MAP), intracavitary ECG (IC) and leads I, II and III during carotid sinus massage (CSM). The first two complexes are without P waves, but with atrial activity on intracavitary recordings. The seventh complex is a dissociated one, and the last two are with normal P waves. Paper speed is 50 mm/sec.
REFERENCES 1. BELLET, S AND JEDLICKA, J: Sinoventricular conduction and its relation in man. Circulation 41:935, 1970 2. VASSALLE,M AND HOFFMAN, B F: The spread of sinus activation during potassium administration. Circ Res 17:285, 1965 3. BELLET, S: Clinical Disorders of the Heart Beat. Lea and Febiger, Philadelphia, 1971 4. JAMES,T N: The connecting pathways between the sinus node and between the right and left a t r i u m in the h u m a n heart. Am H e a r t J 66:498, 1963 5. COTOI,S AND POP, T: Paralizie atriala persistenta. Med Int 25:8, 1005, 1973
6. HARRIS, C L AND BALDWIN,B J: Permanent atrial paralysis. J Electrocardiol 9:81, 1974 7. DEMOTS, H, BRODEUR, M T H AND RAHIMTOOLA, S H: Concealed sinus rhythm. A cause ofmisdiagnosis of digitalis intoxication. Circulation 50:632, 1974 8. KHAN, H, HAIDER, R, BOUGHNER, D R, OAKLEY, C M AND GOODWIN, J F: Sinus rhythm with absent P waves in advanced rheumatic disease. Am J Cardiol 32:93, 1973 9. JACOBSON, L B: Sinoventricular conduction during atrial arrest. J Electrocardiol 5:385, 1972 10. COTOI, S AND DRAGULESCU,S: Complex atrial a r r h y t h m i a s studied by suction electrode technique. Am Heart J 90:241, 1975
J. ELECTROCARDIOLOGY, VOL. 11, NO. 1, 1978
Intermittent Concealed Atrial Conduction Demonstrated Through Intracavitary Leads BY S. COTOI, M.D., C. GEORGESCU, M.D. AND D. MOLDOVAN, M.D.
recorded on the ECG. In order to analyse the atrial activity more completely, carotid sinus massage (CSM) was used. During CSM it was possible to record on the ECG a transition from complexes with normal P waves to complexes without P waves, but normal atrial activity, as demonstrated by i n t r a c a v i t a r y electrogram and right atrial monophasic action potential, was recorded simultaneously (Fig. 2). In Fig. 3, the transition from complexes without P waves to complexes with P waves was recorded, with unchanged atrial activity on the intracavitary recordings.
SUMMARY An intermittent vanishing of the P wave from a s t a n d a r d electrocardiogram (ECG) while normal atrial activity was recorded on intraeavitary leads was observed in a 58 year old man. This i n t e r m i t t e n t c o n c e a l e d atrial conduction is d i s c u s s e d . The absence of the P wave from the electrocardiogram has been reported in m a n y situations. 1~ An uncommon electrocardiographic finding, consisting of the unexpected, brief disappearance of the P wave, was observed, although intraatrial activity recorded on intracavitary electrogram was unchanged. We feel t h a t t h i s r a r e s i t u a t i o n m e r i t s publication.
DISCUSSION The persistence of conduction over the specialized a t r i a l t r a c t s in conditions of h y p e r k a l e m i a has been demonstrated. The impulse is transmitted to the ventricles without P wave inscription. This phenomenon is called sino-ventricular conduction. 1-4 The lack of P wave inscription may also occur in a t r i a l s t a n d s t i l l , in m i d a t r i o ventricular junctional r h y t h m , in sinoatrial block, and when there has been extensive destruction of atrial myocardium in advanced rheumatic h e a r t disease. 3,~9 It is difficult to explain our patient's normal atrial activity, demonstrated on intracavitary recordings but hidden from time to time on the ECG. Taking into account sinoventricular conduction a l o n g w i t h n o r m a l p o t a s s i u m levels, we may consider t h a t our recording was obtained only from a specialized conduction pathway. In our opinion the other situations in which the P wave is not recorded on the ECG ought to be discarded. We consider this case to be interesting because of the unexpected vanishing of the P wave from the ECG while normal atrial activity is recorded on intracavitary recordings. It is difficult to explain this situation, which we have called " i n t e r m i t t e n t concealed atrial conduction."
CASE REPORT A 58 year old man with coronary heart disease was hospitalized because of signs of congestive h e a r t failure. His daily medications included digoxin (0.5 mg) and furosemide (80 mg). Physical examination revealed no unusual signs, the laboratory data were within normal ranges (no hyperkalemia or hyponatremia), and there were no signs of digitalis toxicity. However, from time to time and for short periods, a lack of P wave was observed in all the ECG leads, but without changes in the ventricular rate (Fig. 1). Using a suction bipolar electrode catheter, 1~ we recorded monophasic action potential from the right atrium, finding normal atrial activity even when the P wave was not From the F i r s t Medical Clinic, Tg.Mures, Romania. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. w solely to indicate this fact. Reprint requests to: S. Cotoi, M.D., Clinica I-a Medicala, 4300 Tg. Mures, Romania.
25 ~ s e :
Fig. 1. Standard ECG leads III and aVF, recorded simultaneously. The first four complexes before the ventricular premature beat are without P wave, and the last four ones with evident P wave. Paper speed is 25 mm/sec.
~
i,
Ill
i~.~.____ d
',~
'
_..~.,-----
.
aN
85
fl
~
V----"
,
~,..,
,,L.
,-,~,,,,-.
86
COTOI ET AL
,.j,,
i c
*"k
P "
'
"
i
5o
~z.sec
Fig. 2. Simultaneous recording of right atrial monophasic action potential (RA MAP), intracavitary ECG (IC), and leads I, II and III during carotid sinus massage (CSM). The first complex is a normal one, then during CSM there are no P waves, but normal atrial activity on the intracavitary recordings. The last two complexes, recorded later, are with normal P waves. Paper speed is 50 mm/sec.
i
Fig. 3. Simultaneous recording of right atrial monophasic action potential (RA MAP), intracavitary ECG (IC) and leads I, II and III during carotid sinus massage (CSM). The first two complexes are without P waves, but with atrial activity on intracavitary recordings. The seventh complex is a dissociated one, and the last two are with normal P waves. Paper speed is 50 mm/sec.
REFERENCES 1. BELLET, S AND JEDLICKA, J: Sinoventricular conduction and its relation in man. Circulation 41:935, 1970 2. VASSALLE,M AND HOFFMAN, B F: The spread of sinus activation during potassium administration. Circ Res 17:285, 1965 3. BELLET, S: Clinical Disorders of the Heart Beat. Lea and Febiger, Philadelphia, 1971 4. JAMES,T N: The connecting pathways between the sinus node and between the right and left a t r i u m in the h u m a n heart. Am H e a r t J 66:498, 1963 5. COTOI,S AND POP, T: Paralizie atriala persistenta. Med Int 25:8, 1005, 1973
6. HARRIS, C L AND BALDWIN,B J: Permanent atrial paralysis. J Electrocardiol 9:81, 1974 7. DEMOTS, H, BRODEUR, M T H AND RAHIMTOOLA, S H: Concealed sinus rhythm. A cause ofmisdiagnosis of digitalis intoxication. Circulation 50:632, 1974 8. KHAN, H, HAIDER, R, BOUGHNER, D R, OAKLEY, C M AND GOODWIN, J F: Sinus rhythm with absent P waves in advanced rheumatic disease. Am J Cardiol 32:93, 1973 9. JACOBSON, L B: Sinoventricular conduction during atrial arrest. J Electrocardiol 5:385, 1972 10. COTOI, S AND DRAGULESCU,S: Complex atrial a r r h y t h m i a s studied by suction electrode technique. Am Heart J 90:241, 1975
J. ELECTROCARDIOLOGY, VOL. 11, NO. 1, 1978