Acta med. scand. Vol. 197, pp. 403408,

1W5

REGISTRATION OF SINUS NODE RECOVERY TIME IN PATIENTS WITH SINUS RHYTHM AND IN PATIENTS WITH DYSRHYTHMIAS Helge Grendahl, MBlfrid Miller and Egil Sivertssen From Medical Department VIII, Ullevdl Hospital, Oslo, Norway

Abstract. Sinus node recovery time (SRT) after rapid atrial pacing has been recorded in 66 patients, 28 with coronary heart disease, 11 with advanced AV block, 10 with sick sinus syndrome and 17 with paroxysmal tachyarrhythmias. In patients with a normal functioning sinus node SRT was related to the basal heart rate. On an average SRT was 130% of the basal P-P interval with an upper limit of 160%. In patients with a presumed normal atrial function the mean SRT was found to be 1080 msec, with an upper limit of 1500 msec. This corresponds with previously published observations. In all 5 patients examined, preceptor blockade (propranolol 5 mg i.v.) prolonged SRT. The prolonged SRT was related to sinus bradycardia. Verapamil (Isoptin' 5 mg i.v.) had no effect of SRT in the 7 patients examined. The observation of an SRT of more than 1500 msec indicates a poor sinus node function. Recording of a normal SRT, however, cannot exclude a sinus node dysfunction, as normal SRT is occasionally found even in patients with a clinically proved dysfunction.

T h e clinical manifestations of sinus node dysfunction include sinoatrial block, sinus arrest, sinus bradycardia and tachybradycardia syndrome. In patients in whom these disturbances are recorded or suspected a complete evaluation of the sinus node function is warranted. Methods for examination of the sinus node function a r e at present insufficient. It has not been possible t o record either ECGs from the sinus node in patients, or the sinoatrial transmission time. T h e sinus node automaticity, however, c a n be tested by recording the postpacing suppression. This interval is called the sinus node recovery time (SRT).SRT can be recorded after induction of a supraventricular extrasystole by atrial pacing (4), or more conveniently after abrupt cessation of atrial overdrive pacing ( 3 , 4 , 6 ) . T h e purpose of the present study has been to record SRT in patients with a presumably normal

sinus node function, and in patients with clinical signs of sinus node dysfunction.

METH O D S Atrial pacing was performed with bipolar pacing electrodes introduced pervenously from the right cubital or the femoral vein. The pacing electrodes were placed adjacent to the sinus node in the upper posterolateral part of the right atrium. Usually two pacing catheters were introduced, and intraatrial P waves were recorded from one electrode, while the other was used for pacing. In the first 10 patients examined, however, only one electrode was used, and the P waves had to be detected from the extremity leads I, 11,111, and the precordial lead V1. Medtronic external pacemaker type 5837 was used. The electrode position was accepted when pacing threshold was 3 mA or less. The atria were paced with an impulse twice threshold value at rates of 100, 120, and 140/min. At each rate, pacing was discontinued after 60 sec, spontaneous rhythm recorded for 20 sec and pacing resumed for another 60 sec. Thus 2 observations were made for each pacing rate, and the longest SRT observed after each pacing rate was used for further analyses. The interval between the fifth and sixth normal P wave after atrial pacing was found to be representative for the basic atrial rhythm in most of the patients, and it was used in calculations as the patients' basal P-P interval. When atrial rhythm was irregular, the average of the five following P-P interval was used. P-P intervals of 5000 msec or more were defined as sinus arrest. ECG was recorded on a Mingograph, paper speed 50 mmlsec, and the intervals were measured on the ECG paper. For the statistical analysis the paired 1-test was used. MATERIAL SRT was recorded in 66 patients, 28 of whom had routine right heart catheterization in the preoperative investigation for coronary heart disease (CHD). Eleven patients with advanced AV block were examined in connection with registration of His' bundle potentials or introduction of a temporary pacemaker electrode. Seventeen patients Acta med. scand. 197

404

H . Grendahl et al.

Table I. Sinus node recovery time in patients with coronary heart disease

Pat. no. 1

2 3 4 5

6 7 8 9 10

II 12 13 14 IS 16 17 18 19 20 21 22 23 24 25 26 27 28

Mean

SRT (msec)

SRT (% of basal P-P interval)

Auial pacing rate

Atrial pacing rate

I00

120

140

100

1 130 1 140 1 020

I 180

lo00 1 160 920 1 120 lo00 1 I50 I260 1 100 1 120 980 1030 1 280

loo0 1 160 950 I030 950 1040 1230 1 070 1 160 920 1080 1 230 930 890 800 780 a30 980 1 380 1200 I440 I 050 1 150 1 120 1 120 1070t30

1 150 1 130 1 150 980

138 1 I9 136 135 I 34 112 124 133 128 148 130 125 127 143 145 137 125 I I6

1 150 1 220

960

860 800 690

-

720 1390 1 340 1 420 1 330 I 160 1190 I 080 1090f36

I190 900 1010

950 1 120 980 1200 1040 1 360

950 1030 670

-

820 830 1 280 1220

-

1330 1 200 1 020 1 150 1070+34

were examined due to episodes of paroxysmal tachyarrhythmia and 10 for suspected sinus node dysfunction. The effect of Preceptor blockade and of verapamil on SRT was examined in 5 and 7 patients, respectively with CHD and presumably normal sinus node function. RESULTS Patients without symptoms of sinus node dysfunction In the 28 patients with CHD and presumably normal sinus node function, average SRT was 1080 msec. After an atrial pacing rate of 100/min mean SRT was 1 090 msec, after a pacing rate of 140/min mean SRT was 1070 msec. These differences were, however, not significant (Table I). Two patients (nos. 10 and 18) who developed anginal pain during atrial pacing at a rate of 140/min, had shorter SRT at that rate. A positive correlation was found between SRT and the basal endogenous P-P interval (after a pacing rate of 100/min, R =0.88, after a pacing rate of Acta med. scand. 197

111

1I4 I36 132 128 123 145 147 159 131+2

120

140

128

121 1 I7 129 120

1 I8

153 137 129 120 1I9 127 135 149 124 126 125 137 158 137 127 133 131 143 126 134 126 130 91 137 143 142 13152

-

112 1I9 129

-

127 I I4 130 137

-

134 138 147 I I4

-

138 I34 120 124 139 140 142 I28 12af2

120/min, R=0.79, after a pacing rate of 140/min, R=0.82). The mean SRT was about 130% of the basal P-P interval at all pacing rates. Patients with AV block Eleven patients with advanced AV block were examined. One of them had a congenital and 10 an acquired AV block (Table 11). The mean SRT was 1070 msec after a pacing rate of 100/min and 1 190 msec after a pacing rate of 140/min. These differences were not statistically significant. Mean SRT for all observations was 1080 msec. In these patients the basal P-P intervals were often difficult to assess due to irregular atrial rhythm. In 4 patients P-P intervals were shorter if a QRS complex appeared inbetween the two P waves. In one case P waves tended to follow immediately after the start of QRS complexes, probably due to supraventricular extrasystoles, and not to retrograde AV conduction. In 6 patients the longest P-P interval did not follow immediately after termination of the atrial

Sinus node recovery time

405

Table 11. Sinus node recovery time in patients with advanced AV block

SRT (msec)

SRT (% of basal P-P interval)

Atrial pacing rate

Atrial pacing rate

7

Pat. no.

100

120

I40

100

I20

I40

1

1 140

2" 3b 4'

950 I 340 1 240 1300 1 060 1 180 1200

I 170 I 050 I 340 1 200 1 200 1 040

1 240 1 100

146 139 146 I24 129 117 120 I26 I60 135 129 134+4

I3 1 146

I4 I 153 97 123 114 127 I38 1 I3 100 185 166 132f8

5c.a

6d 7 8 9 10' I1 Mean

1200 1 070

1160 1 170k30

1 140

I 030 930 I410 I 320 1 170kSO

980 1 320 1 140

I 140 I 380 1 180 840 I 460 1360 I 190k60

' Shorter P-P intervals with time relation to ventricular spontaneousP-P interval 1 700 msec.

systole. Congenital AV block.

pacing in one or more registrations. One of these patients (no. 3) had on one occasion a spontaneous P-P interval of 1700 msec. In the other patients all spontaneous P-P intervals were less than 1500 msec. In the patients with A V block, SRT was on an average 13 1 % of the basal P-P interval.

Patients with sick sinus syndrome Ten patients with a clinical diagnosis of sick sinus syndrome were examined. The diagnosis was made before the SRT examination and was based on history and ECG recordings. Duration of symptoms and relevant clinical data are listed in Table 111. The group included patients with marked tendency to sinus arrest as well as patients with moderate symp-

Ill 108 124 1 I8 1I4 1 I8 122 178 145 129f6

Unpredictable variations in P-P interval, longest Supraventricular extrasystoles.

toms due to intermittent sinoatrial block. Eight of the patients had symptoms which warranted pacemaker implantation. In this group SRT varied greatly between patients, and in many of them between registrations (Table IV). In 2 of the 10 patients SRT was shorter than 1500 msec in all registrations. In one of them, however, P-P intervals of more than 1500 msec duration were observed during the next 8 sec after discontinuation of atrial pacing. In 6 cases long P-P intervals, even sinus arrest, were observed a few seconds after atrial pacing as shown in Fig. 1. When episodes of sinus arrest (SRT>S sec) were excluded, a mean SRT of I 780 msec was observed. Sinus arrest was seen in 2 patients after pacing at a

Table 111. Clinical data on patients irith sick sinus syndrome Pat. no.

Age (y.)

Symptoms

Duration (Y.)

Tachyarrhythmias

AV block

Permanent pacemaker

2: 1

Yes

1

Parox. flutter

64 53 68 76 80 77

Congestive he!art failure Dizziness Dizziness Dizziness CHD Dizziness Dizziness

3 3 20 I 9 I

Parox. flutter Parox. nodal tach. Parox. atrial tach.

8

64

Dizziness, syncope

14

Parox. flutter

9 10

53 64

Syncopes Dizziness

6 6

Parox. flutter

I

70

2 3 4 5 6 7

Atrial pacing 120: Wenc kebach Atrial pacing 100: Wenckebach

Yes Yes No Yes Yes No Yes Yes Yes Acra med. scand. 197

406

H . Grendahl et a / .

Sinus arrest

Sinus arrest

1015 1 120

1 150 1 070 Sinus arrest

shorter than 1500 msec at all pacing rates. Two of the patients (nos. 4 and 81, both with CHD, had SRT of 1500 msec or more. Patient 8 had left ventricular aneurysm and paroxysmal ventricular tachycardia. During 2 weeks' observation in a CCU sinus arrest, SA block or extreme bradycardia had never been observed. In patient 4, who had had paroxysmal supraventricular tachycardia for many years, one possible episode of sinus arrest had been seen on the oscilloscope screen during observation in a CCU. Irregular atrial rhythm after termination of atrial pacing was very common in these patients, usually due to supraventricular extrasystoles, in some cases to ventricular extrasystoles and retrograde P waves. In one patient atrial pacing was followed by a supraventricular tachycardia for a few seconds. In 6 patients the longest P-P interval did not follow immediately after termination of the atrial pacing in one or more of the registrations. Effect of drugs on SRT

Table IV. Sinus node recovery time (msec) in 10 patients with sick sinus node Atrial pacing rate Pat. no.

120

100

1"

1 420 4600

2

Sinus arrest

140

-

Sinus arrest

-

Sinus arrest Sinus arrest

1 350

30

-

Sinus arrest Sinus arrest

1 650

4"

I 550 1700 800 2 150 I360 1360 1220

1320 I430 4 500 lo00 1 320 1200 1 050 I 580 Sinus arrest

3 800 4 400 2 940 1 500 1 360 1200 1 loo I 500 Sinus arrest

5 0

6" 7

1600

8

3 260 2 730 1 120 1320 Sinus arrest

9 10

Meanb

-

Sinus arrest

Sinus arrest Sinus arrest

Sinus arrest

I870+/-270

1 SO+/-330

1920+/-30

In one or more of the registrations one of the following P-P intervals was longer than the SRT. Episodes of sinus arrest (SRTX000 msec) have been excluded. rate of 100/min, and in 4 patients after pacing at a rate of 140/min. Patients with paroxysmal tachyarrhythmias

Seventeen patients with paroxysmal tachyarrhythmias were examined (Table V). Fifteen had SRT Pacing rate

Pbcing rate

100

In 5 CHD patients SRT was recorded 10 min after P-receptor blockade (propranolol 5 mg i.v.). SRT increased from 1080+/-40 to 1300+/-50 msec, and this increase was statistically significant (p =0.001). This prolongation of SRT corresponded to the bradycardia induced by the P-receptor blockade. The basal P-P intervals increased from 830 to 950 msec. The SRT as a percentage of the basal P-P intervals was unchanged (13 1 % before, 133 % after propranolol).

Pacing rate

120

'PP

')rap Pot. no. 1

2 3 4 5

6

Fig. I . Rhythm diagram in

7 8 9

10 2

4

6

8

Time (rec.) after stop of pacing Acra med. scand. 197

patients with sick sinus node. Atrial rhythm during the first 8 sec after atrial pacing (pacing rates 100, 120, 140/ min). l=P waves, - - -=P-P intervals longer than 1500 msec.

Sinus node recovery time

407

Table V. Sinus node recovery time in patients with tachyarrhyrhmias PAT=paroxysmal tachyarrhythmia,PAF=paroxysmal atrial fibrillation, VES =ventricular extrasystole, PVT=paroxysmal ventricular tachycardia, AES=atrial extrasystole ~~

Pat. no. 1

2 3 4 5 6 7 8 9 10 11 12 13 14

I5 16 17

Mean

Age (y.)

50 82 45 73 59 55 31 62 64 62 54

67 66 55 67 69 20

Type of tachyarrhythmia PAT PAT PAF PAT PAT PAT VES PVT VES AES Prox. AV block I PVT PAT PAF PAT PAT PAT

SRT (msec)

SRT (% of basal P-P interval)

Atrial pacing rate

Atrial pacing rate

100

120

1 050

980 1300 1 040 I 500 940 950

1040 1 220 1 500 lo00 lo00 1 160 I550 1 050 1 260 1 020 1300 1 460 1 300 1460 970 800 I 190+/-50

140 970 1 340

1300 I 070 880 1 160 980 1 150

1190

I 820 1 060 1350

1000

1 060 1 250 1 200 I 320 1 260 1 080 900

1 130

I190+/-60

In 7 CHD patients SRT was recorded 10 min after verapamil (Isoptin@5 mg i.v.). N o significant effect was observed on the SRT. The basal heart rate was unchanged. SRT was 1150 msec before and 1180 msec after verapamil. The difference was not statistically significant. SRT as a percentage of the basal P-P interval was 134 before as well as after verapamil. DISCUSSION Recordings of SRT are easy to perform and can be done in connection with other invasive diagnostic procedures. It is advantageous to have an intraatrial ECG for recording of P waves, because P waves in standard ECG leads sometimes are obscured by QRS or T waves. Atrial extrasystoles are also usually easier to detect from an intraatrial recording. In many patients a different duration of SRT can be observed from one registration to another and therefore more than one recording should be taken in each case. In patients with no clinical dysfunction of the sinus node we found an average SRT of 1080 msec, and in no case an SRT longer than 1500 msec. These figures may be taken as normal values for

1 120 1 380 1 250 940 900 I IlO+l -40

100

120

140

I28 1 02 160 142 119 113 135 I15 135 136

I20 146 135 130 I22 102 138 I27 137 132

121 146 140 129

120 1 I7 130 137 127 137 129 129+/- 3.0

127 120 I24 143 107

105

132 I26 125 111

140 I08 141 1 I9 154 138 120 155 l28+/- 3.0 129+/-4.0

SRT. On an average SRT was 130% of the basal P-P interval and in no case more than 160%. Our observations correspond fairly well with previously published results ( 1 , 3 , 5 , 6 ) . In some of the patients with clinically proved poor sinus node function we have recorded a normal SRT on one or more occasions. The recording of a normal SRT therefore does not exclude the possibility of a poorly functioning sinus node. In some instances the following spontaneous P-P intervals are longer than the SRT and may exceed 1500 msec. We have observed that even sinus arrest may occur a few seconds after atrial pacing. It was previously found by others (3, 4) that the duration of SRT normally is not related to the atrial pacing rate. Mandel et al. ( 3 ) , however, observed a reduction in SRT after atrial pacing rates of more than 150. We made the same observation of shortened SRT in 2 patients, who developed angina pectoris at atrial pacing rates of 140/min. Narula et al. (4) observed that SRT lengthened as the pacing rate increased in patients with sinus bradycardia. In the present study sinus arrest occurred more frequently after rapid atrial pacing than after atrial pacing at a moderate rate in patients with sick sinus syndrome. Acra med. scand. 197

408

H . Grendahl et al.

To our knowledge, the effect of 6-receptor blockade on SRT in man has not been published before. In the present study a significantly prolonged SRT was observed, and this prolongation was probably related to the bradycardia induced by the preceptor blockade. Verapamil is reported to prolong SRT (2). In this study, however, verapamil had no effect either on SRT or on the spontaneous atrial rate. REFERENCES 1. Dhingra, R. C., Rosen, K. M. & Rahimtoola, S. H.:

Normal conduction intervals and responses in sixtyone patients using His bundle recording and atrial pacing. Chest 64: 5 5 , 1973.

Acta med. scand. 197

2. Husaini, M. H.,Kvasnicka, J., Ryden, L. & Holmberg, S.: Action of verapamil on sinus node, atrioventricular, and intraventricular conduction. Brit. Heart J. 35: 734, 1973. 3. Mandel, W., Hayakawa, H., Danzig, R. & Marcus, H. S.: Evaluation of sinoatrial node function in man by overdrive suppression. Circulation 44: 59, 1971. 4. Narula, 0. S . , Samet, P. & Javier, R. P.: Significance of the sinus-node recovery time. Circulation 45: 140, 1972. 5. Rich, J.

M.,Meisner, M. H., Fontana, M. E. & Wooley, C. F.: Electrophysiologic stress test in man: Sino-atrial node suppression and recovery. J. Lab. clin. Med. 78:805, 1971. 6. Rosen, K. M., Loeb, H. S., Sinno, M. Z., Rahimtoola, S.H. & Gunnar, R. M.: Cardiac conduction in patients with symptomatic sinus node disease. Circulation 43: 836, 1971.

Registration of sinus node recovery time in patients with sinus rhythm and in patients with dysrhythmias.

Sinus node recovery time (SRT) after rapid atrial pacing has been recorded in 66 patients, 28 with coronary heart disease, 11 with advanced AV block, ...
360KB Sizes 0 Downloads 0 Views