Penkov, N.

Sirakova, V.

Tzvetkov, R.

English

Varna Medical University Press: Journals

II. Clinical problems • E A R L Y A T R I A L P A C I N G T E S T FOR M Y O C A R D I A L C O N T R A C T I L I T Y E V A L U A T I O N IN P A T I E N T S W I T H U N S T A B L E A N G I N A P E C T O R I S N. Penkov, V. Sirakova, R. Tzvetkov Key-words: angina pectoris — transvenous atrial pacing — myocardial contractility — echocard iography — e lec t rocard iography Echocardiography is an easi ly accessible method for ev a k a i i c n of left ventr icular function and has an essential importance in determination of prog-nosis and behaviour of ischemic heart disease ( I H D ) patients . I t is known that some I H D patients have normal left ven t r i cu la r function at rest (3) .On the other hand, echocardiography examination of patients during phys ica l loading is prac t ica l ly very difficult (3 , 7, 9, 10). Tha t is why it is appropriate to perform echocardiography determination of the parameters of left ventr icular function during an a t r i a l pacing test. The purpose of this study is to ascertain how left ventr icular cont rac t i l i ty changes during a t r ia l pacing in patients wi th unstable angina pectoris ( U A P ) . Material and methods 6 patients (4 males and 2 females) w i th U A P (crescent angina on the back-ground of an old stable one) aged between 48 and 66 years (mean age of 58.3 years) were studied. U A P patients were diagnosed after W H O modified c r i t e r i a (4) . Treatment of patients was carried out by modern medicines resulting in overcoming of endangering symptoms in an Intensive Coronary U n i t and then — in complete s tabi l izat ion of the state in a general cardiological d ivis ion (5) . A n a t r i a l pacing test and a simultaneous recording of M-mode echocardio-graphy, apexcardiography ( A C G ) , phonocardiography ( P C G ) and E C G was performed 3 t i l l 7 days after complete c l i n i ca l s tabi l iza t ion (on the background of treatment administered on the corresponding day after examinat ion) . A t r i a l pacing test was performed wi th a bipolar electrode introduced in the r ight at-r ium through the r ight subc lav ian or femoral ve in (6) . Pac ing was rea l i zed by means of portable pacemaker of the «Medt ronic» 5375 model. W e started w i t h 10 beats per minute above the patients ' heart rate and then increased to 20 beats of each step ( 1 , 2, 6, 7 ) . E v e r y step was of 2 m i n durat ion. E lec t rocard io gram wasrecorded on 6-channel E C G N E K - 4 prior to test at 12 leads and during the pacing and the rest i tut ion period at the end of every minute at 6 p record ia l leads (Vx-e) w i t h veloci ty of m o v i n g band of 5 0 mm/sec. Simultaneous echo-apex-phono:ardiographic recording was carr ied out at left half-side patient's position from a standard parasternal position prior to and after every step of 60 N . P e n f o v , V. S i r a k o v a , R . T z v e t k o V pacing. A r t e r i a l pressure was measured after Korotkov ' s method prior to, du­r ing pacing at the end of every step as w e l l as during the restitution period at the end of every minute. A t r i a l pacing test was cDnsidered positive when is­chemic ECG-changes apoeared (horizontal ST-segment depression > 0.1 m V wi th time duration > 0.08 sec in one or more leads) and/or in case of angina pectoris at tack (6). When ECG-changes were absent pacing was continued t i l l the appearanc'e of disorder of a t r iovent r ic j l a r conduction and/or t i l l the appe-rance of heart rate of 160 — 170 per minute. Mean velocity of circumferential fiber shortening ( % / ) and the ra t io bet­ween systolic a r te r ia l pressure and telesystolic left vent r icu lar volume index ( s A P — T S L V V I ) prior to s t imulat ion, w i th prethreshnld (one step of pacing prior to the appear&nce of i s :hemic ECG-changes) a n l threshold (a t the step of pacing when ischemic ECG-changes appeared) he i r t rate were estimated to evaluate the dynamics of myocardia l contract i l i ty . Results and discussion A t r i a l pacing test is positive i n a l l the p a t i e n t s — 5 patients react with ST-depression only and one patient w i th ST-depression combined wi th angina pectoris attack. Parameters characterizing myocard ia l contract i l i ty demonstrate a biph a-sic dynamics. W i t h increasing heart rate ( H R ) from 65.8 fc 12.8 up to 83.3 + 8.2, V c f increases by 13,5 per cent (p > 0.10). W i t h further H R increase V c f begins to decrease exceeding i ts i n i t i a l one only by 5.4 percent at prethresh-old H R but being below it by 4.5 per cent at threshold H R (table 1). After in i ­t i a l increase in a l l the patients V begins to decrease i n 3 patients 2 steps prior to, in 2 ones — one step prior to, and in one patient at threshold H R . V c f ex T a b 1 е 1 Parameters characterizing left ventricular function •Л , i f . T S L V D x + s A % towards i n i t i a l rates T D L V D x ± s Л % towards i n i t i a l rates s A P - T S L V V I ra t io x ± s A % towards i n i t i a l rates I n i t i a l rates M a x i m a l ra tes H e a r t ra te M i n i m a l rates H e a r t rate A t prethreshold heart ra te A t treshe heart ra t 3 . 3 3 + 0 . 6 7 2.94 + 0.56 ( + 1 1 . 7 % ) 9 3 . 3 + 1 6 . 3 3 . 1 4 + 0 . 5 3 ( + 5 . 7 % ) 3 . 2 7 ± : 0 . 5 1 ( + 1 . 8 % ) 5.01 + 0.56 4.37 + 0.60 4.22^=0.54 1 .11+0 .17 1 .26+0 .10 ( + 1 3 . 5 % ) 8 3 . 3 + 8 . 2 1 .17+0.12 ( + 5 . 4 % ) 1 .06+0.12 ( - 4 . 5 % ) 3 . 5 3 + 1 . 7 2 4 . 8 8 + 2 . 5 4 ( + 3 8 . 2 % ) 9 0 . 2 + 2 0 . 7 3 . 9 4 + 1 . 6 0 ( + 1 1 . 6 % ) 3.59:4:1.34 ( + 1 . 7 % ) 1 :)< I I E a r l y a t r i a l p a c i n g test fo r . . . 61 — , ' • • • ceeds in i t i a l values in 2 patients at threshold H R but it is below it in 4 ones. Although of different qua i t i t a i ve charaeteris-ique, the dynamics of s A P — T S L V V I rat io is analogous. W i t h H R increase from 65.8 ± 12.8 t i l l 9 0 . 2 b± 20.7 s A P — T S L V V I ratio increas es by 38.2 per cent (p > 0.10) . W i t h further H R increase s A P — T S L W I r a t i ' о decreases thus exceeding the i n i t i a l level L y 11.6 percent at pre threshold H R but by 1.7 percent at threshold one (table . ) . W i t h i n i t i a l H R increase s A P — T S L V V I rat io incerases in 5 patients but emains unchanged in one patient. T h i s ratio decreases in one patient 2 steps r r i c r to, in 3 patients one step prior to and in two patients at threshold H R when H R continues to increase* s A P — T S L W I rat io is over the i n i t i a l leve l in 3 patients and below it in the rest 3 ones at threshold H R . P Th i s dynamics of contract i l i ty parameters is real ized on the background of the following changes of left ventr icular s ize. Teledias tol ic left ventr icular dimension ( T D L V D ) progressively decreases wi th increasing H R as i t s change between pretoreshold and threshold H R is considerably less than that between the other neighbouring steps (table 1). Telesystol ic left ven t r i cu l a r dimension ( T S L V D ) decreases bv 11.7 per cent (p > 0.10) when H R increases from 65.8 2= 12.8 t i l l 93.3 =t 16.3. W i t h further H R increase T S L V D increases and at pretreshold H R it is by only 5.7 per cent over the i n i t i a l values w h i l e at threshold H R it by 1.5 per cent below them (table 1). T S L V D begins to increase 2 steps prior to threshold H R in 3 patients, oiu step prior to threshold H R in 2 ones, and at threshold H R in one patient . I t exceeds i n i t i a l va lues at treshold H R in 5 patients and lies under them in one pat ient only. A t r i a l pacing test performed synchronously wi th an echocardiography examination enables: first, to follow-up the changes of left ventr icular funct ion after loading, and second, to establish the degree of t ime correlation between functional disturbances and ischemic E C G changes. I n concordance wi th other authors 1 data (7) we f ind out two phases in the dynamics of T S L V D and V c f as w e l l . I n i t i a l T S L V D reduction and V d increase, respectively, can be explained by an imporoved myocardial con t rac t i l i ty . T h i s is confirmed by the i n i t i a l increase of s A P / T S L V V I ra t io as a cont rac t i l i ty in­dex established in our study. Th i s index depends to a smaller extent on the changes of opposite and pre l iminary load of the left ventr icle as compared w i th Vet and T S L V D both. Supervening T S L V D increase and V c f and s A P T S L V V I rat io decrease, respectively, reflect myo:a rd ia l cont rac t i l i ty diminution as related to beginning ischemia . S i m i l a r l y to other authors ( 1 , 2, 8 / 1 0 , 11), we also establish that in most patients contract i l i ty changes precede ischemic E C G ones. I t stresses t ha t s A P - T S L W I rat io and V c f both remain over i n i t i a l values t i l ! threshold H R inc lus ive , although progressively d iminishing, in some of the patients w h i l e they decrease down to values below the i n i t i a l ones i n other patients. W i t h the lat ter , it probably refers to cer ta in manifestation of an ex i s t i ng latent cont rac­t i l i t y deficiency not detectable during pat ient ' s examinat ion at rest. The de­terminat ion of the significance of these two typeso f dynamics of cont rac t i l i ty parameters for the. further state of left ventr icular function and for patients ' prognosis requires addi t ional prospective observations. A n other fact of interest i s that one that «breaking» occurs ear l ie r w i th T S L V D and V e f than wi th s A P - T S L W I rat io. I t is probably due to discrete changes of the ar ter ial pressure (sys tol ic pressure increase by 3 per cent). The smal l number of patients under mvestigati6n, hoewver, does not enable us 62 N . Penkov , V . S i r a k o v a , R . T z v e t k o v to draw an expl ic i t conclusion about the additional loading which has induced ischemia having altered contract i l i ty and passed into isehemia provoking is­chemic E G G changes. We conclude that echocardiographic study of U A P patients during a t r i a l pacing test demonstrates a biphasic dynamics of contract i l i ty indices . Contra­c t i l i t y suppression preeedes the appiarance of ischemic E C G changes. I n order to speifying the place of the method when determining left ventr icular function and prognosis as wel l as when following-up of the effect of drug or surgical tre­atment of U A P one requires the investigation of a larger contingent of patients. R E F E R E N C E S j f ! . 1. Б у н и н, Ю . A . , Н. Д . Б е л о у с о в а, Г . В . Г р у д ц ы н. Кардиология, 1982, № 1, 3 8 — 3 9 . , — 2. Г а с и л и н, В . С . , О . П . Ш е в ч е н к о , А. Л . А г а п о в , А. Б . К а р д а н о в , Р . М . , . X а ф и з о в . Кардиология, 1980, № 12, 4 9 — 5 3 . — 3. М а р к а р я н, С . С . Кардиология, 1986, № 1, 1 0 0 — 1 0 4 . — 4. П е н к о в , Н. К а н д . д и с . В а р н а , В М И , 1981. 209 с. — 5. П е н к о в , Н . X . К а н о н о в . Вътр. болести, 1983, Ш 2, 74—76. — 6. П е н к о в , Н . , Р . Ц в е т к о в , В . С и р а к о в а . В : Н а ц . -к о н г р . по в ъ т р . б о л е с т и , V I I I . Т о л б у х и н , 2 3 — 2 5 , I X . 1988 г. С б . р е з ю м е т а , . с . 2 5 . — 7. Я н о в-с к и и, Г. В . , Л . Г. В о р о н к о в , Л . А . С т а д н ю к , А . П . С т е п а н с н к о. Кардиология, 1986, № 4, 8 0 — 8 1 . — 8. В a h 1 е г, R . С , С . А . Macleod. Circula­tion, 43, 1971, N 3 407—418. — 9. C h a p m a n, Р . А . , Т . P . D o y l e , P . J . T r o u p , С . M . G г о s s. L . S . W a n n. Circulation, 70, 1984, N 3, 445—450. — 10. D е h m е r, C . J . , B . G . F i r t h, P . N i с о d, S . E . L е w i s, . D . I I i 1 1 i s. Amer. Heart'J. 106, 198.4, N 1, P t . 1, 1 И — 1 2 4 . - 11. Mancini, G . B . J. , et a l . Amer. J. Cardiol., 53. 1984, N2, 4 5 6 - 4 6 1 . Р А Н Н И Й ТЕСТ С ПРЕДСЕРДНОЙ С Т И М У Л Я Ц И Е Й Д Л Я О Ц Е Н К И С О К Р А Т И М О С Т И М И О К А Р Д А У Б О Л Ь Н Ы Х С Н Е С Т А Б И Л Ь Н О Й С Т Е Н О К А Р Д И Е Й И. Пенков, В. Сиракова, Р. Цветков Р Е З Ю М Е П р о в е д е н а о ц е н к а и з м е н е н и й с о к р а т и м о с т и м и о к а р д а у шести б о л ь н ы х с н е с т а б и л ь н о й с т е н о к а р д и е й п о с л е и х к л и н и ч е с к о г о с т а б и л и з и р о в а н и я . П о с р е д с т в о м э х о к а р д и о г р а ф и и М - т и п а б ы л у с т а н о в л е н т е л е с и с т о л и ч е с к и й р а з м е р л е в о г о ж е л у д о ч к а с е р д ц а , с р е д н я я с к о ­р о с т с о к р а щ е н и я ц и р к у м ф е р е н т н ы х в о л о к о н ( V е ) и о т н о ш е н и е м е ж д у с и с т о л и ч е с к и м а р т е ­р и а л ь н ы м д а в л е н и е м и т е л е с и с т о л и ч е с к и м о б ъ е м о м л е в о г о ж е л у д о ч к а . П а р а м е т р ы с о к р а т и ­мости п о к а з ы в а ю т д в у ф а з н у ю д и н а м и к у . П о с л е п е р в о н а ч а л ь н о г о п о в ы ш е н и я с к о р о с т и со­к р а щ е н и я ц и р к у м ф е р е н т н ы х в о л о к о н и о т н о ш е н и я м е ж д у с и с т о л и ч е с к и м а р т е р и а л ь н ы м д а в л е н и е м и г е л е с и с т о л и ч е с к и м о б ъ е м о м л е в о г о ж е л у д о ч к а , р е с п е к т и в н о п о н и ж е н и я т е л е ­с и с т о л и ч е с к о г о о б ъ е м а , п р и д а л ь н е й ш е м у в е л и ч е н и и ч а с т о т ы с т и м у л я ц и и V c и о т н о ш е н и я с и с т о л и ч е с к о е а р т е р и а л ь н о е д а в л е н и е — т е л е е н с т о л и ч е с к и й о б ъ е м л е в о г о ж е л у д о ч к а н а ч и ­н а ю т у м е н ь ш а т ь с я , а т е л с с и с т о л и ч е с к и й о б ъ е м л е в о г о ж е л у д о ч к а н а ч и н а е т у в е л и ч и в а т ь с я . Н а р у ш е н и я с о к р а т и м о с т и п р е д ш е с т в у ю т п щ е м н ч е с к и с З К Г - и з м с п с п и я (т. и . п о р о г о в а я ч а с т о т а ) . ' ' ° - п - г т »*; •:• > >, | : :с • •>,. п / . [) '!••. . П ы ш п ' Ы 

EARLY ATRIAL PACING TEST FOR MYOCARDIAL CONTRACTILITY EVALUATION IN PATIENTS WITH UNSTABLE ANGINA PECTORIS

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EARLY ATRIAL PACING TEST FOR MYOCARDIAL CONTRACTILITY EVALUATION IN PATIENTS WITH UNSTABLE ANGINA PECTORIS

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