Optimized Hemodynamics by Implantation of a Dual Chamber Pacemaker After Heterotopic Cardiac Transplantation R.W. BREEDVELD, L.M. VAN G E L D E R , A . G . MITCHELL,* C ) . PEELS, M. YACOUB,* and M.LH. EL GAMAL From the Department of Cardiology. Catharina Hospital, Eindhoven, The Netherlands and the "Department of Cardiology and Cardiac Surgery, Harefield Hospital, Middlesex, United Kingdom BREEDVELD, R.W., ET AL.: Optimized Hemodynamics by Implantation of a Dual Chamber Pacemaker
After Heterotopic Cardiac Transplantation. A patient who underwent prior heterotopic cardiac transplantation had persistent complaints of dyspnea, palpitations, and fatigue in spite of normal pump /unction of the donor heart. Repeated Holter monitoring excJuded paroxysmal arrhythmias. It was thought that synchronization of both heart rates might alleviute his symptoms. The intrinsic heart rate of the donor heart was 90 beats/min, the recipient heart was 60 beats/min with acceleration up to 130 beats/min on exercise. A DDD pacemaker was implanted, the atrial lead was positioned in the right ventricle of ihe donor heart and (he ventricular lead in the atrium of the recipient heart. Search for an optimal AV interval was evaluated by echo-DoppIer and intraarterial pressure recordings. By increasing the AV interval from 125 io 300 msec, (he maximum aortic flow velocity of the recipient heart increased from 1.0 to 1.2m/sec. Left ventricular end-diasiolic diameter remained unchanged, Je/(ven(ricular end-systolic diameter decreased from 52 to 48 mm. Wall motion of ihe recipient left ventricle improved. At an AV in(erval of 125 msec there was alternate systolic contraction of both hearts, resulting in arterial pressure waves at a rate of 180/min. This did not relieve his symptoms and he complained further of headaches. At an AV interval of 300 msec contraction of the recipient heart just preceded that of the donor heart, resulting in arterial pressure waves at a rate of 90/min, normalization of the waveform, relief of symptoms, and improvement of exercise tolerance. (PACE, Vol. 15, March 1992) DDD pacemaker, heierotopic cardiac transplantation
Case Report A 44-year-old man underwent heterotopic cardiac transplantation in 1984 at Harefield Hospital, Middlesex, United Kingdom. He suffered from heart failure due to impaired left ventricular function after several myocardial infarctions. Heterotopic cardiac transplantation was chosen because the patient had pulmonary hypertension. A second heterotopic cardiac transplantation
Address for reprints: L.M. van Gelder, Department of Cardiology, Catharina Hospital, Michelangegiolaan 2, 5623 E] Eindhoven, The Netherlands. Fax: 40-447885, Received July 10, 1991; revision November 7, 1991; accepted November 19, 1991.
274
was carried out in 1988 because of rejection of the donor heart associated with severe heart failure. After the second cardiac transplantation, he continued to complain of dyspnea, palpitations, and fatigue. Ultrasound examination of the donor heart showed an excellent function. Right ventricular biopsy of the donor heart showed no evidence of rejection. The ECG at rest showed two independent heart rhythms. The donor heart was in sinus rhythm with a rate of 90 beats/min, the recipient heart, also in sinus rhythm, had a rate of 60 beats/ min (Fig. 1). Holter monitoring revealed acceleration of the recipient heart rate up to 110 beats/min, but there was no significant change in rate of the donor
March 1992
PACE, Vol. 15
DDD PACEMAKER AFTER HETEROTOPIC CARDIAC TRANSPLANTATION
Figure 1. Three-channel ECG, lead I, right precordia] (RP), and lead III, Recipient heart is best reflected in lead I, sinus rhythm 60 beats/min. Donor heart is best represented in RP lead, sinus rhythm 86 beats/min.
heart. Dissociation of both rhythms seemed a likely cause that could aggravate his complaints. To solve this problem a DDD pacemaker (Siemens Pacesetters, 2010, Siemens Pacesetter, Inc., Sylmar, CA, USA) was implanted. The atrial lead was positioned in tbe rigbt ventricle of the donor beart, the ventricular lead was positioned in the right atrium of tbe recipient heart (Fig. 2). Tbe pacemaker was programmed in DDD mode, with a lower rate of 80 ppm, an AV interval of 125 msec, and an upper rate of 110 ppm. In this setting tbe QRS complex of tbe donor beart was sensed at tbe atrial lead and after 125 msec (AV interval] tbe atrium of the recipient beart was stimulated by tbe ventricular impulse, thus synchronizing both heart rhythms. An AV interval of 125 msec was chosen in order to alternate heartbeats, with equal intervals between tlie QRS complexes. This setting, iiowever, did not improve bis exercise tolerance or relieve bis symptoms, in addition he complained of headaches.
PACE, Vol. 15
Figure 2. Anleroposterior chest X ray showing (he pacing .sj'.s-(em ivilh (he fJlrial lead positioned in the ventricle of the donor heart and the ventricuiar lead in the atrium of the recipient heart.
March 1992
275
BREEDVELD, ET AL.
At physical examination we found a diastolic blood pressure of 100-110 mmHg, with a normal systolic pressure of 130 mmHg. Because of persistent complaints, we decided to evaluate the role of tbe programmed AV interval on arterial pressure waveform and left ventricular function of the recipient heart. Methods A 6 French sbeatb was introduced in the right femoral artery in order to measure and record atrial pressure. After 10 minutes, arterial pressure was recorded during echo-Doppler examination of tbe left ventricle of tbe donor heart. A 2.5 MHz transducer was used with tbe patient lying on bis left side, to record a parasternal short-axis view at tbe level of the papillary muscle. End-systolic and end-diastolic diameters were measured. Left ventricular wall motion was studied. From the apical position, the maximal flow over the aortic valve was measured as well as the acceleration and deceleration times. Subsequently, the AV interval was increased hy 25 msec and the procedure was repeated. Measurements were performed until the maximum AV interval of 300 msec was reached. Finally, tbe pacing system was switched off completely in order to study arterial blood pressure and echocardiographic findings with complete dissociation of both heart rhythms.
Results ECG and Pressure Wave Findings At an AV interval of 125 msec tbere was alternating contraction of hoth hearts with an equal interval between the QRS complexes (Fig. 3A). In the arterial pressure tracing, alternating pulsations were recorded. Tbe blood pressure generated by the recipient heart was 156/116 mmHg and the donor heart 168/118 mmHg. The effective pulsation rate at tbis setting was 180 ppm. Changing the AV interval to 200 msec (Fig, 3B] increased the interval hetween the QRS complex of tbe donor heart and recipient heart, while tbe interval hetween tbe QRS complex of the recipient beart and donor beart was decreased.
276
Arterial pressure generated by the donor beart was 176/116 mmHg, recipient heart systolic pressure was 159 mmHg, but diastolic pressure could not be measured because of shortening of the interval between QRS complexes of recipient and donor beart. In tbis pbase there was partial overlap of botb pressure tracings. At an AV interval of 300-msec contraction of the recipient heart just preceded that of the donor heart, creating a pressure waveform that was similar to a normal arterial pressure with a systolic value of 176 mmHg and a diastolic value of 108 mmHg. Tbe effective pulsation rate in this setting was 90 beats/min, wbicb is 50% of tbe rate wben an AV interval of 125 msec was programmed (Fig. 3C). When the pacing system was switched off completely tbere was dissociation of both rbytbms causing a bizarre pressure waveform pattern. The most physiological waveform, with highest systolic and lowest diastolic values occurred when tbe contraction of tbe recipient beart just preceded tbe donor beart (Fig. 4). Echocardiographic and Doppler Findings Table I sbows tbe ond-diastolic and end-systolic diameters of the donor heart recorded at the level of tbe papillary muscle in the parasternal short-axis view, at different AV intervals. By increasing tbe AV interval no significant cbange occurred in left ventricular end-diastolic diameter. The left ventricular end-systolic diameter, however, decreased by 6%, from 52 to 49 mm. The cross-section area of the left ventricle at this level also decreased from 21.7 to 18.8 cm2 (13.5%), Table II sbows tbe acceleration and deceleration time of aortic flow and tbe calculated total ejection time together with the maximum aortic flow velocity at different AV intervals. With an increase of the AV interval from 125 to 300 msec there was a decrease of 23% in acceleration time. Deceleration time decreased by 30%, total ejection time decreased by 27.5%. Maximum aortic flow velocity increased by 20%. Hemodynamic Evaluation Right and left heart pressures were measured during annual evaluation at Harefield hospital, 1
March 1992
PACE, Vol. 15
DDD PACEMAKER AFTER HETEROTOPIC CARDIAC TRANSPLANTATION
T
I
180
:m:m>::::: .•.::::::::•::::::::::::
AV:3OO:
Figure 3. Arterial pressure (racing with (A] AV interval 125 msec, (B) AV interval 200 msec, and (CJ AV interval of 300 msec. Arrows indicate pacemaker spike, ventricular impulse slimuiating the recipient atrium. Note aJlernad'ng beating of both hearts at an AV interval of 125 msec and an effective pulse rate of 180 beats/min while there is normalization of the wave pattern and an effective pulse rate of 90 beats/min at an AV interval of 300 msec, r = QRS recipient heart, d = QRS donor heart.
year after programming the AV interval to 300 msec. Recipient heart: wedge pressure a wave = 25 mmHg, v wave ^ 25 mmHg, mean 18 mmHg. Left ventricular end-diastolic pressure 18 mmHg. Shortening of AV interval to 150 msec. Wedge pressure a wave = 34 mmHg, v wave = 24 mmHg, mean 20 mmHg. Left ventricular end-diastolic pressure 28 mmHg. Left ventricular end-diastolic pressure in the donor heart rose from 18 to 24 mmHg after programming the AV interval from 300 to 150 msec. Pacemaker Response to Exercise During exercise there was an increase in heart rate of tbe recipient beart, accelerating up to 130 beats/min. Tbere was no significant increase in tbe heart rate of the donor heart. When tbe recipient heart rate just exceeded the donor beart rate, the
PACE. Vol. 15
pacing system was inhibited because atrial depolarization of the recipient beart was sensed at the ventricular channel (sensitivity 1.0 mV). During this period pseudosynchronization was observed witb complete inhibition of the pulse generator. Slight increase in heart rate of the recipient heart, however, started a different form of synchronization. At the programmed setting of lower rate (80 ppm = 750 msec) and an AV interval of 300 msec the VA interval is 450 msec. This implicated tbat after sensing the recipient atrial depolarization [Pr) at the ventricular sensing amplifier, the donor beart was stimulated 450 msec (VA interval) after detection of Pr. Tbus, syncbronization was acbieved again by pacing the donor ventricle synchronous with atrial depolarization of the recipient heart (Fig. 5).
March 1992
277
BREEDVELD, ET AL.
Figure 4. Arterial pressure recording after switching off the pacing system. There is dissociation of donor rhythm (d) and recipient rhythm fr) resulting in a bizarre waveform pattern.
Table 1.
Table II
Echocardiographic Findings (Recipient Heart)
Echo-Dopplei• Findings (Recipient Heart)
AVI (msec)
LVedd (mm)
LVesd (mm)
LVcsa (cm=)
AVI (msec)
At (msec)
Dt (msec)
Et (msec)
AoF (msec)
125 200 300
56 56.5 56.5
52 50.5 49
21.7 — 18.8
125 200 300
110 90 85
200 160 140
310 250 225
1.0 1.1
AVI = atrioventricular interval. LVedd ^ left ventricular enddiastolic diameter, LVesd = left ventricular end-systolic diameter, LVcsa = left ventricular cross-section area (end-systolic).
Discussion There are only a few reports that descrihe implantation of pacemaker systems after cardiac transplantation. The main indication for pacing was chronotropic incompetence due to sinus node dysfunction of the donor heart.^ In the majority of patients pacing was performed hy implantation of
278
1.2
AVI = atrioventricular interval, At = acceleration time, Dt = deceleration time, Et = ejection time, AoF = aortic flow velocity.
a DDD pacemaker in the donor heart.^ A single report described recipient p wave synchronized pacing of the donor atrium.'^ All pacing systems were implanted after orthotopic cardiac transplantation. There are no published reports, to the best of our knowledge, on the use of cardiac pacing after heterotopic cardiac transplantation. The indica-
March 1992
PACE, Vol. 15
DDD PACEMAKER AFTER HETEROTOPIC CARDIAC TRANSPLANTATION
Figure 5. ECG lead Ul, showing synchronization at rest (Heart Rate donor fHRd] > Hearl Rate recipient [HRr]) and during exercise fHRd < HRr).
Table III. Electrode Configuration and Drawbacks Atrial Lead
Ventricular Lead
I.
Atrium donor
Atrium recipient
II.
Atrium donor
Ventricle recipient
III.
Ventricle donor
Atrium recipient
IV.
Ventricle donor
Ventricle recipient
PACE, Vol. 15
Drawbacks Dependent on P wave sensing. Short AV interval, no synchronization on exercise. Timing contraction of recipient heart depends on AV conduction. Dependent on P wave sensing. No AV synchrony and artificial activation of recipient heart. AV interval equal to PR donor, no synchronization during exercise. Timing contraction of recipient heart depending on AV conduction. No AV synchrony and artificial activation of recipient heart. Short AV interval, no synchronization on exercise.
March 1992
279
BREEDVELD, ET AL.
tion for pacing in our patient differed from that after orthotopic cardiac transplantation. Our patient suffered from dyspnea, palpitations, and fatigue related to asynchronous pump function of both hearts. Synchronization of both hearts was easily achieved by implantation of a dual chamber system. It was apparent that the optimal AV interval (300 msec) determined by this examination resulted in improvement of his physical condition, completely relieved his symptoms, and increased his exercise tolerance. A totally unexpected effect of this long AV interval was synchronization of both hearts during exercise when the recipient heart rate increased above the donor rate. Other possibilities of synchronizing both hearts by dual chamber pacing and their drawbacks are summarized in Table III. Implantation of
the ventricular lead in the recipient atrium maintains normal AV sequence and normal activation of the recipient ventricle. Implantation of the atrial lead in the donor ventricle provides reliable sensing. In settings requiring a short AV interval [I, IV) no synchronization is obtained during exercise. All modalities in Table III have sensing in the donor heart at rest in common. Pacemaker systems with the atrial electrode sensing in the recipient heart require lower rate pacing above donor heart rate at rest. This implicates continuous pacing at a lower rate > 95 ppm in our patient. The pacing modality used in our patient allowed synchronization of botb hearts, with normal AV sequence and intrinsic activation of both ventricles at rest. During exercise artificial activation of the donor ventricle was accepted in order to maintain synchronization of both hearts when recipient heart rate exceeded donor heart rate.
References 1. Zmyslinski RW, Warner MG. Diethrich EB. Symptomatic sinus node dysfunction after heart transplantation. PACE 1988; 11:445-448. 2. Markewitz A, Kemkes BM, Reble B, et al. Particularities of dual chamber pacemaker therapy in patients
280
after orthotopic heart transplantation. PACE 1987; 10:326-332. 3. Markewitz A, Osterholzer C, Weinhold C, et al. Recipient P wave synchronized pacing of the donor atrium in a heart-transplanted patient: a case study. PACE 1988; 11:1402-1404.
March 1992
PACE, Vol. 15
After Heterotopic Cardiac Transplantation. A patient who underwent prior heterotopic cardiac transplantation had persistent complaints of dyspnea, palpitations, and fatigue in spite of normal pump /unction of the donor heart. Repeated Holter monitoring excJuded paroxysmal arrhythmias. It was thought that synchronization of both heart rates might alleviute his symptoms. The intrinsic heart rate of the donor heart was 90 beats/min, the recipient heart was 60 beats/min with acceleration up to 130 beats/min on exercise. A DDD pacemaker was implanted, the atrial lead was positioned in the right ventricle of ihe donor heart and (he ventricular lead in the atrium of the recipient heart. Search for an optimal AV interval was evaluated by echo-DoppIer and intraarterial pressure recordings. By increasing the AV interval from 125 io 300 msec, (he maximum aortic flow velocity of the recipient heart increased from 1.0 to 1.2m/sec. Left ventricular end-diasiolic diameter remained unchanged, Je/(ven(ricular end-systolic diameter decreased from 52 to 48 mm. Wall motion of ihe recipient left ventricle improved. At an AV in(erval of 125 msec there was alternate systolic contraction of both hearts, resulting in arterial pressure waves at a rate of 180/min. This did not relieve his symptoms and he complained further of headaches. At an AV interval of 300 msec contraction of the recipient heart just preceded that of the donor heart, resulting in arterial pressure waves at a rate of 90/min, normalization of the waveform, relief of symptoms, and improvement of exercise tolerance. (PACE, Vol. 15, March 1992) DDD pacemaker, heierotopic cardiac transplantation
Case Report A 44-year-old man underwent heterotopic cardiac transplantation in 1984 at Harefield Hospital, Middlesex, United Kingdom. He suffered from heart failure due to impaired left ventricular function after several myocardial infarctions. Heterotopic cardiac transplantation was chosen because the patient had pulmonary hypertension. A second heterotopic cardiac transplantation
Address for reprints: L.M. van Gelder, Department of Cardiology, Catharina Hospital, Michelangegiolaan 2, 5623 E] Eindhoven, The Netherlands. Fax: 40-447885, Received July 10, 1991; revision November 7, 1991; accepted November 19, 1991.
274
was carried out in 1988 because of rejection of the donor heart associated with severe heart failure. After the second cardiac transplantation, he continued to complain of dyspnea, palpitations, and fatigue. Ultrasound examination of the donor heart showed an excellent function. Right ventricular biopsy of the donor heart showed no evidence of rejection. The ECG at rest showed two independent heart rhythms. The donor heart was in sinus rhythm with a rate of 90 beats/min, the recipient heart, also in sinus rhythm, had a rate of 60 beats/ min (Fig. 1). Holter monitoring revealed acceleration of the recipient heart rate up to 110 beats/min, but there was no significant change in rate of the donor
March 1992
PACE, Vol. 15
DDD PACEMAKER AFTER HETEROTOPIC CARDIAC TRANSPLANTATION
Figure 1. Three-channel ECG, lead I, right precordia] (RP), and lead III, Recipient heart is best reflected in lead I, sinus rhythm 60 beats/min. Donor heart is best represented in RP lead, sinus rhythm 86 beats/min.
heart. Dissociation of both rhythms seemed a likely cause that could aggravate his complaints. To solve this problem a DDD pacemaker (Siemens Pacesetters, 2010, Siemens Pacesetter, Inc., Sylmar, CA, USA) was implanted. The atrial lead was positioned in tbe rigbt ventricle of the donor beart, the ventricular lead was positioned in the right atrium of tbe recipient heart (Fig. 2). Tbe pacemaker was programmed in DDD mode, with a lower rate of 80 ppm, an AV interval of 125 msec, and an upper rate of 110 ppm. In this setting tbe QRS complex of tbe donor beart was sensed at tbe atrial lead and after 125 msec (AV interval] tbe atrium of the recipient beart was stimulated by tbe ventricular impulse, thus synchronizing both heart rhythms. An AV interval of 125 msec was chosen in order to alternate heartbeats, with equal intervals between tlie QRS complexes. This setting, iiowever, did not improve bis exercise tolerance or relieve bis symptoms, in addition he complained of headaches.
PACE, Vol. 15
Figure 2. Anleroposterior chest X ray showing (he pacing .sj'.s-(em ivilh (he fJlrial lead positioned in the ventricle of the donor heart and the ventricuiar lead in the atrium of the recipient heart.
March 1992
275
BREEDVELD, ET AL.
At physical examination we found a diastolic blood pressure of 100-110 mmHg, with a normal systolic pressure of 130 mmHg. Because of persistent complaints, we decided to evaluate the role of tbe programmed AV interval on arterial pressure waveform and left ventricular function of the recipient heart. Methods A 6 French sbeatb was introduced in the right femoral artery in order to measure and record atrial pressure. After 10 minutes, arterial pressure was recorded during echo-Doppler examination of tbe left ventricle of tbe donor heart. A 2.5 MHz transducer was used with tbe patient lying on bis left side, to record a parasternal short-axis view at tbe level of the papillary muscle. End-systolic and end-diastolic diameters were measured. Left ventricular wall motion was studied. From the apical position, the maximal flow over the aortic valve was measured as well as the acceleration and deceleration times. Subsequently, the AV interval was increased hy 25 msec and the procedure was repeated. Measurements were performed until the maximum AV interval of 300 msec was reached. Finally, tbe pacing system was switched off completely in order to study arterial blood pressure and echocardiographic findings with complete dissociation of both heart rhythms.
Results ECG and Pressure Wave Findings At an AV interval of 125 msec tbere was alternating contraction of hoth hearts with an equal interval between the QRS complexes (Fig. 3A). In the arterial pressure tracing, alternating pulsations were recorded. Tbe blood pressure generated by the recipient heart was 156/116 mmHg and the donor heart 168/118 mmHg. The effective pulsation rate at tbis setting was 180 ppm. Changing the AV interval to 200 msec (Fig, 3B] increased the interval hetween the QRS complex of tbe donor heart and recipient heart, while tbe interval hetween tbe QRS complex of the recipient beart and donor beart was decreased.
276
Arterial pressure generated by the donor beart was 176/116 mmHg, recipient heart systolic pressure was 159 mmHg, but diastolic pressure could not be measured because of shortening of the interval between QRS complexes of recipient and donor beart. In tbis pbase there was partial overlap of botb pressure tracings. At an AV interval of 300-msec contraction of the recipient heart just preceded that of the donor heart, creating a pressure waveform that was similar to a normal arterial pressure with a systolic value of 176 mmHg and a diastolic value of 108 mmHg. Tbe effective pulsation rate in this setting was 90 beats/min, wbicb is 50% of tbe rate wben an AV interval of 125 msec was programmed (Fig. 3C). When the pacing system was switched off completely tbere was dissociation of both rbytbms causing a bizarre pressure waveform pattern. The most physiological waveform, with highest systolic and lowest diastolic values occurred when tbe contraction of tbe recipient beart just preceded tbe donor beart (Fig. 4). Echocardiographic and Doppler Findings Table I sbows tbe ond-diastolic and end-systolic diameters of the donor heart recorded at the level of tbe papillary muscle in the parasternal short-axis view, at different AV intervals. By increasing tbe AV interval no significant cbange occurred in left ventricular end-diastolic diameter. The left ventricular end-systolic diameter, however, decreased by 6%, from 52 to 49 mm. The cross-section area of the left ventricle at this level also decreased from 21.7 to 18.8 cm2 (13.5%), Table II sbows tbe acceleration and deceleration time of aortic flow and tbe calculated total ejection time together with the maximum aortic flow velocity at different AV intervals. With an increase of the AV interval from 125 to 300 msec there was a decrease of 23% in acceleration time. Deceleration time decreased by 30%, total ejection time decreased by 27.5%. Maximum aortic flow velocity increased by 20%. Hemodynamic Evaluation Right and left heart pressures were measured during annual evaluation at Harefield hospital, 1
March 1992
PACE, Vol. 15
DDD PACEMAKER AFTER HETEROTOPIC CARDIAC TRANSPLANTATION
T
I
180
:m:m>::::: .•.::::::::•::::::::::::
AV:3OO:
Figure 3. Arterial pressure (racing with (A] AV interval 125 msec, (B) AV interval 200 msec, and (CJ AV interval of 300 msec. Arrows indicate pacemaker spike, ventricular impulse slimuiating the recipient atrium. Note aJlernad'ng beating of both hearts at an AV interval of 125 msec and an effective pulse rate of 180 beats/min while there is normalization of the wave pattern and an effective pulse rate of 90 beats/min at an AV interval of 300 msec, r = QRS recipient heart, d = QRS donor heart.
year after programming the AV interval to 300 msec. Recipient heart: wedge pressure a wave = 25 mmHg, v wave ^ 25 mmHg, mean 18 mmHg. Left ventricular end-diastolic pressure 18 mmHg. Shortening of AV interval to 150 msec. Wedge pressure a wave = 34 mmHg, v wave = 24 mmHg, mean 20 mmHg. Left ventricular end-diastolic pressure 28 mmHg. Left ventricular end-diastolic pressure in the donor heart rose from 18 to 24 mmHg after programming the AV interval from 300 to 150 msec. Pacemaker Response to Exercise During exercise there was an increase in heart rate of tbe recipient beart, accelerating up to 130 beats/min. Tbere was no significant increase in tbe heart rate of the donor heart. When tbe recipient heart rate just exceeded the donor beart rate, the
PACE. Vol. 15
pacing system was inhibited because atrial depolarization of the recipient beart was sensed at the ventricular channel (sensitivity 1.0 mV). During this period pseudosynchronization was observed witb complete inhibition of the pulse generator. Slight increase in heart rate of the recipient heart, however, started a different form of synchronization. At the programmed setting of lower rate (80 ppm = 750 msec) and an AV interval of 300 msec the VA interval is 450 msec. This implicated tbat after sensing the recipient atrial depolarization [Pr) at the ventricular sensing amplifier, the donor beart was stimulated 450 msec (VA interval) after detection of Pr. Tbus, syncbronization was acbieved again by pacing the donor ventricle synchronous with atrial depolarization of the recipient heart (Fig. 5).
March 1992
277
BREEDVELD, ET AL.
Figure 4. Arterial pressure recording after switching off the pacing system. There is dissociation of donor rhythm (d) and recipient rhythm fr) resulting in a bizarre waveform pattern.
Table 1.
Table II
Echocardiographic Findings (Recipient Heart)
Echo-Dopplei• Findings (Recipient Heart)
AVI (msec)
LVedd (mm)
LVesd (mm)
LVcsa (cm=)
AVI (msec)
At (msec)
Dt (msec)
Et (msec)
AoF (msec)
125 200 300
56 56.5 56.5
52 50.5 49
21.7 — 18.8
125 200 300
110 90 85
200 160 140
310 250 225
1.0 1.1
AVI = atrioventricular interval. LVedd ^ left ventricular enddiastolic diameter, LVesd = left ventricular end-systolic diameter, LVcsa = left ventricular cross-section area (end-systolic).
Discussion There are only a few reports that descrihe implantation of pacemaker systems after cardiac transplantation. The main indication for pacing was chronotropic incompetence due to sinus node dysfunction of the donor heart.^ In the majority of patients pacing was performed hy implantation of
278
1.2
AVI = atrioventricular interval, At = acceleration time, Dt = deceleration time, Et = ejection time, AoF = aortic flow velocity.
a DDD pacemaker in the donor heart.^ A single report described recipient p wave synchronized pacing of the donor atrium.'^ All pacing systems were implanted after orthotopic cardiac transplantation. There are no published reports, to the best of our knowledge, on the use of cardiac pacing after heterotopic cardiac transplantation. The indica-
March 1992
PACE, Vol. 15
DDD PACEMAKER AFTER HETEROTOPIC CARDIAC TRANSPLANTATION
Figure 5. ECG lead Ul, showing synchronization at rest (Heart Rate donor fHRd] > Hearl Rate recipient [HRr]) and during exercise fHRd < HRr).
Table III. Electrode Configuration and Drawbacks Atrial Lead
Ventricular Lead
I.
Atrium donor
Atrium recipient
II.
Atrium donor
Ventricle recipient
III.
Ventricle donor
Atrium recipient
IV.
Ventricle donor
Ventricle recipient
PACE, Vol. 15
Drawbacks Dependent on P wave sensing. Short AV interval, no synchronization on exercise. Timing contraction of recipient heart depends on AV conduction. Dependent on P wave sensing. No AV synchrony and artificial activation of recipient heart. AV interval equal to PR donor, no synchronization during exercise. Timing contraction of recipient heart depending on AV conduction. No AV synchrony and artificial activation of recipient heart. Short AV interval, no synchronization on exercise.
March 1992
279
BREEDVELD, ET AL.
tion for pacing in our patient differed from that after orthotopic cardiac transplantation. Our patient suffered from dyspnea, palpitations, and fatigue related to asynchronous pump function of both hearts. Synchronization of both hearts was easily achieved by implantation of a dual chamber system. It was apparent that the optimal AV interval (300 msec) determined by this examination resulted in improvement of his physical condition, completely relieved his symptoms, and increased his exercise tolerance. A totally unexpected effect of this long AV interval was synchronization of both hearts during exercise when the recipient heart rate increased above the donor rate. Other possibilities of synchronizing both hearts by dual chamber pacing and their drawbacks are summarized in Table III. Implantation of
the ventricular lead in the recipient atrium maintains normal AV sequence and normal activation of the recipient ventricle. Implantation of the atrial lead in the donor ventricle provides reliable sensing. In settings requiring a short AV interval [I, IV) no synchronization is obtained during exercise. All modalities in Table III have sensing in the donor heart at rest in common. Pacemaker systems with the atrial electrode sensing in the recipient heart require lower rate pacing above donor heart rate at rest. This implicates continuous pacing at a lower rate > 95 ppm in our patient. The pacing modality used in our patient allowed synchronization of botb hearts, with normal AV sequence and intrinsic activation of both ventricles at rest. During exercise artificial activation of the donor ventricle was accepted in order to maintain synchronization of both hearts when recipient heart rate exceeded donor heart rate.
References 1. Zmyslinski RW, Warner MG. Diethrich EB. Symptomatic sinus node dysfunction after heart transplantation. PACE 1988; 11:445-448. 2. Markewitz A, Kemkes BM, Reble B, et al. Particularities of dual chamber pacemaker therapy in patients
280
after orthotopic heart transplantation. PACE 1987; 10:326-332. 3. Markewitz A, Osterholzer C, Weinhold C, et al. Recipient P wave synchronized pacing of the donor atrium in a heart-transplanted patient: a case study. PACE 1988; 11:1402-1404.
March 1992
PACE, Vol. 15
