P Wave Dispersion in Patients with Mitral Stenosis and Effects of Percutaneous Mitral Balloon Valvuloplasty on P Wave Dispersion

Tiirk Kardiyol Dem

Arş

2002; 30: 16 1-165

P Wave Dispersion in Patients with Mitral Stenosis and Effects of Percutaneous Mitral Balloon Valvuloplasty on P Wave Dispersion

Hasan TURHAN, MD, Ertan YETKiN, MD, Yüksel AKSOY, MD, Orhan MADEN, MD, Kubilay ŞENEN, MD, M. Birhan YILMAZ, MD, Mehmet İLERi, MD, Ramazan AT AK, MD, Sengül CEHRELİ, Asso. Prof., E mine KÜTÜK, Asso, Prof.

Türkiye Yiiksek ihtisas Hospital, Department ofCardiology, Ankara, Turkey

MiTRAL DARLIKLI HASTALARDA P DALGA DİSPERSİYONU VE PERKÜTAN MiTRAL BALON VALVÜLOPLASTİ İŞLEMİNİN P DALGA DİSPERSİYONU ÜZERİNE ETKİSİ ÖZET

P dalga dispersiyonu (PDD ), yeni bir elektrokardiyogra- fik parametre olup, siniizal

uyarılarm

illlra-atriyal ve in- ter-atriyalnonhomojen ve kesintili iletilmesi ile

ilişkilidir.

PDD maksimum ve minimum P dalga siireleri arasmdaki fark olarak ifade edilebilir. Yaktn zamanda

yaymlannuş çaltşmalarda uzamtş

P dalga siiresi ve

artmtş

P dalga dis- persiyonunun yiiksek atrial fibrilasyon riski ile

ilişkili olduğu bildirilmiştir.

Bu

^çaltşnwmn

amact mitral darltklt has talarda P dalga dispers iyo nunu belirlem ek ve perkiitan mitral balon valviiloplasti (PMBV)

işleminin

P dalga dispersiyonu üzerine etkis ini

değerlendirmektir.

Çaltşmaya

PMBV adayt 29 mitral darltklt hasta (26 bay- an , 3 erkek;

yaş

33±6 ytl) ve 27

sağltklt

gönüliii (24 bay- an, 3 erkek;

yaş

32±7 ytl) kontrol grubu olarak dahil edil- di. İşlemden bir giin önce hasta ve kontrol grubundaki tüm

kişilerin elektrokardiyogramları

çekildi ve transtora- sik ekokardiyogramlart yaptldt. İşlem sonrast birinci gün, birinci ay, ve alttl/C t ayda

ça!tşmaya

daltil edilen hasta gruplanndaki tüm

kişilerin elektrokardiyogranıları

çekildi. Hasta grubundaki

kişilerin

transtorasik

ekokardiyogramları işlem

sonrast birinci gün, birinci ay ve allinet ayda tekrarlandt. Çekilen elektrokardiyogram- lardan maksimum ve minimum P dalga süreleri ölçiildii ve PDD hesaplandi. Mitral darltklt hasta grubunda mak-

simımı

P dalga siiresi ve PDD

sağlıklı

kontrol grubuna göre istatistiksel olarak

anlamlı

dere cede daha yüksek

saptandı

(p<O.OOJ ) . Ancak, minimum P dalga süreleri

acısmdatı

hasta ve kontrol grubu

arasında

istatistiksel ol- arak

anlan·ılt

fark yoktu. PMBV sonrast birinci gün, birin- ci ay ve

allincı

ayda yaption ölçiimlerde maksimum P dal- ga süresi ve PDD'nun

işlem

önçesi ölçülen bazal

değerlere

göre ilerleyici bir

şekilde

istatistikse l olarak onlamit derecede

azaldığı

tespit edildi (p<O.OOJ ). Birinci gün, birinci ay ve

altmcı

ayda ölciilen maksimum P dalga süresi ve PDD kendi aralannda

karşı/aştm/dığında

yine istatistiksel olarak anlam lt azalma tespit edildi (p<O.O l ).

Ancak, minimum P dalga s ürelerinde onlamit bir Reccived: 7

Augusı,

rcvision acceptcd 25

Deccınber

2002 Corrospending Address: Hasan Turhan,

Türkocağı

caddesi 20.

sokak no:

ın

Balgat, 06520 Ankara, Turkey Tlf: (0312) 286 7658 E-mail: drhturhan@yahoo.com

değişiklik

gözlenmedi. PDD'nda ki a zalma ile ekokardiy- ografik parametrelerdeki düz e/me arasmda istatistiksel olarak onlamit korelasyon sap tanmadt. Sonuç olarak, yüksek atrial fibrilasyon riskini gösteren PDD mitra l darltklt hastalarda salJitklt bireylere göre istatistiksel ola- rak onlamit derecede dctlw yüksektir. PMBV

sonrası

PDD ktsa ve uzun dönemde istatistiksel olarak mtlamlt dere- cede

düşmektedir.

Türk Kardiyol Dem

Arş

2002; 30:161-165 Anahtar kelime/er: P dalga dispersiyonu, mitral

^darlığt,

perkiitan mitral balon valviiloplasti

P wave dis persion (PWD) is a new elec trocardio- graphic marke r that has been assoc iated with inho- mogeneous and discontinuous propa gation of sinus impulses (1,2). It can be defined as the difference be- tween ma ximum and m inimum P wave duration.

The prolongation of intraatrial a nd interatrial con- duction time, the inhomoge neous propagation of si- n us impulse s are well known electrophysiological characteristics of the atrium prone to fibri llate ^{( 1,2).}

Furthermore, prolonged P wave durat ion and in- creased PWD have bee n re ported to carry a n in- creased risk for atrial fibrillation (AF) (2,3) . Rheu- matic mitral stenosis (MS) is frequently seen in de- veloping countries and causes significant morbidi ty and mortality

(4).

Percutaneous mitral balloon valvu- loplasty (PMBV) is the procedure of choice in pa- tients who have symptomatic, hemodynamically se- vere MS and are suitable for this procedure

(4-6).

This procedure is high ly successful with a low com- plication rate and significant short- and long-te rm improveme nt in both hemodynamics and symptoms

(7,8).

The objectives of this study were to dete rmine (1)

PWD in patients with MS, and (2) the effects of

PMBVonPWD.

Tiirk Kardiyol

Dem Arş

2002; 30: 161-165

PATIENTS and METHODS

The study population consisted of two groups: Group I consisted o f 29 patients w ith MS (26 women, 3 men; aged 33±6 years) who were candidate for PMBV and group II consis ted of 27 healthy volunteers (24 women, 3 men;

aged 32±7 years). All patients were in sinus rhythm and none of

theın

were taking type I or type lll antiarrhythmic agents. None of the patients had previous history of docu- mented paroxysmal AF. Patients who ·had coronary artery disease, hypertension, diabetes mellitus,

hyperthyroidisnı,

pericardial effusion, chronic obstructive

pulınonary

dis- ease, ve ntricular preexcitation, bundl e branch block, atrio - ventricular conduction abnormalities, or abnormal serum electrolytes were excl uded from the study. Twelve-lead electrocardiogram (ECG) was recorded for each patient one day before PMBV and repeated at

fırst

day, at the e nd of the first month and at sixth month after successful PMBV at a rate of 50 mm/s in the supine position. ECGs were coded and all annotations were masked. P wave du- ration was measured from the onsct to the offset of the P wave. The onset and offset of the P wave were defincd as the junction between the P wave pattern and isoelcctric line. After

coınpletion

of the

ıneasurenıents,

all ECGs we re decoded. PWD was defined as the difference be- twcen maximum and minimum P wave duration. Trans- thoracic and transesophageal echocardiographic

exaınina­

tion were performed 24 hours before procedure and

repeaı­

ed at

firsı

day, at the cnd of the first month and at sixth

ınonth

after PMBV. Mitral val ve

anatoıny

was scored by two dimentional echocardiography on the basis of Wilkins' echo scorring system

(9).

Left atrial

diaıneter

was measured by M-mode ec hocardiog raphy and mitral valve area was calculated by pressure half time method. Mean transmitral diastolic gradients were also calculated by Do ppler stud- ies. Colo r flow Doppler was used to detect the presence of mitral reg urgitation.

Pulınonary

artery systolic pressure was calculated by the help of continuous wave Doppler studies using the Bernoulli

equaıion.

The

ıechnique

of PMBV has previously been deseribed

(5).

PMBV was per- formed by the antegrade, transseptal approach with Ino ue balloon cathetcr (Toray I ndustries, Ine., Houston, Texas).

Right and left heart pressure measurements, including si- mu ltaneous left atrial and left ventricular pressures were obtained before and after PMBV. Oxygen saturation of blood samples from the superior and inferior vena cava, pulmonary artery and aorta were measured before and af- ter PMBV. PMBV procedure considered successfull if the mitral valve area was hig her than 1.5

cmı,

w ithout >2+

mitral reg urg itation and left to right sh u nt (Qp/Qs> 1 .5).

Table I. Effecls of PMBV o n pat ients' cchocardiographic variablcs

Variables Before PMBV

Lefı

atrial

diameıer

(cm) 4.70±0.32 Mitral valve area

(cın2) ı.

1 2±0.2 1 Pulmonary artery pressure (mmHg) 46±8 Mean mitral gradient (mmHg) 14±4

All numeric variables were expressed as mean±SD and categorical variables were expressed as percemage. Statis- tical analysis was performed usi ng unpaired

ı-test,

repeat-

ed-ıneasurcs

analysis of variance and Pearson

correlaıion

test. A p value < 0.05 was considered stati stically

signifı­

cant.

RESULTS

There was no statistically s ignificant diffe rence be- tween two groups in respect to age and gender (p>0.05). All patients s uccess full y unde rwent PMBY. Statistically s ignificant improvement in left atrial diameter, mitra l valve area, pulmonary artery pressure and mean mitral gradient were achieved in all patients (p<O.OOO I in all, table I). Baseline maxi- mum P wave d uration and PWD of group I were sig- nificantl y higher than those of group II (P maxi- mum; 128.6±9.3msec vs I 02.4±7 .8msec, p<O.OO 1, PWD; 54.1±7.3msec vs 26.7±7.5msec, p<O.OO l , res pectively). However there was no statistically significant difference between group I and group II regarding minimum P wave duration (74.3±6.9msec vs 79.4±7.2msec, p>0.05, respect ively). Maximum P wave duration and PWD decreased progressively at first day, at the end of the first month and at sixth mo nth after PMBV (tab le 2). However, no sig- nificant ch ange was d etected be tween echoc- ardiographic variables measured at first day, at the end of the first mo nth and at s ixth month after PMBV (p>0.05 , table 1). There was no statistically significant differe nce between the values of mini- mum P wave duration measured before PMBV, at first day, at the e nd of the first month and at sixth

ınonth

after PMBY(p>0.05, ta ble 2). There was no statis tically s ignifi cant correlation betwee n the de- crease in PWD and the imp rovement in echoca rdio- graphic parameters (p>0.05, table 3). No episode of paroxysmal AF was detected during the 6

ınonth

fol- low-up period.

Arter PMBV

ısı

day*

ısı monUı* 6ıh ıııontlı*

4.40±0.25 4.32±0.58 4.35±0.34

2.07±0.27 2.04±0.38 2.00±0.53

36±7 34±6 35±7

5±3 6±3 5±4

PMBV= percutaneous mitral balloon valvuloplasty *p<O.OOOI vs before PMBV

162

H. Turhan et al.: PWD in Patients

wir

h Mitral Stenosis and Effects of Percutaneous Mitral Balloon Va/vuloplasty on P Wave Dispersion

Tabi e 2. EITects of PMBV on P wave duration a nd dispers ion

Variables Before PMBV After PMBV

ısı

day

ısı ınonth 6ııı ınonlh

P max

(ınsec)

128.6±9.3 118.5±9.2* 113.3±9.5*:1= 105.3±8.*,

P min

(ınsec)

74.3±6.9 75.2±7.21 75.5±8.3t 74.8±8.5t

PWD

(ınsec)

54.1±7.3 4 1.3±8.3* 35.1±8.9*+

29.1±7.7*~

PMBV= percutaneous mitral balloon valvuloplasry; P max= maximum P wave duration; P min= minimum P wave duration;

PWD= P

ıvave

dispersion. *p<O.OOI vs before PMBV. t p>0.05 vs he[01·e PMBV, :f:p<O.OI vs Ist day, fjp<O.OI vs Ist molllh

Table 3. Correlation of P wave dispersion with echocardiographic variables Variables

Before PMBV

r

_ı>

Lefl atrial

diaıncter

(cm) 0.184 0.300 Mitral valve area (cm2) 0.126 0.392 Mean mitral gradient (mmHg) 0.218 0.742

Pulnıonary

artery pressure (mmHg) 0.116 0.549

DISCUSSION

In the present study, we have several main findings:

l) Maximum P wave durati on was s ig nificantly longer and PWD was significantly higher in patients with severe M S than in hea lthy control subjects, 2) Maximum P wave duration and PWD decreased pro- gressively at first day, at the e nd of the first month and at sixth month after PMBY. 3) The decrease in max imum P wave duration and PWD were not cor- related with the improve me nt in left atrial diameter, mitral valve area, pulmonary artery pressure and mean mitral gradient after PMBY.

PWD is a new electrocardiographic marker that has bee n associated w ith the inhomoge neous and discon- tinuous propagation of s inus im pulses

(ı ,2).

lt can be defined as the difference between maximum and minimum P wave duration. Prolongation of intraatri- al and interatrial conduction time and inhomogenous propagation of s inus impu lses are known electro- physiological characteristics of atria prone to fibri l- lation (1,2). Moreover, the corre lation between the presence of intraatrial conduction abnormalities and the induction of paroxysmal atrial fibrillation has been well doc umented

^{(3, lO).}

These electrophys io - logical c harac teristics result in inc reased PWD on

r 0.333 0.278 0.158 0. 128

P Wave Dis persion

After PMBV

ısı

day

ısı

monlh

6ılı

month

ı> r p r

p

0.078 0.438 0.095 0.512 0.126

0.418 0.354 0.247 0.434 0.342

0.748 0.547 0.214 0. 153 0.118

0.508 0.658 0.218 0.352 0.375

electroca rdiographic measurements. Th e refore, PWD ca n be used to separate patients with a high risk of AF during sin us rhythm (3) .

The combination of mitral valve disease and atrial infl ammation secondary to rheuma tic carditis cause left atrial dilatatio n, fibros is within the wall of the atrium and disorganization of the atrial muscle bun- dles (lll. Consequently,

fıbrosis

of the atrial wall and disorganization of atrial muscle bundles leads to elec trica l inhomogene ity, disparate conduc tion ve- locities and inhomogenous refracto ry pe riods with in the atrial myocardium (4,1 1) which reflect on ECG as in creased P wave d uration and PWD (1,2). Apa rt from the pathological changes in a trial tissue, sym- pathetic ne rvous system activation which is s hown to be high in mitral stenosis (12, 1 3) may also increase PWD.

The most s triking finding of our study is that there is

no correlation between the decrease in PWD and im-

provement in ec hocardiograph ic pa rameters after

PMBY . It has been suggested that the prolongation

of P wave duration is an accepted indicator of an in-

teratria l conduction dis turbance wh ich can occur in-

dependent of an increase in atrial s ize ( 1 4). Further-

more , Dilaveris e t al

(1)

have reported that left atrial

Tiirk Kardiyol Dem Arş 2002; 30: 161-165

ma ximal d iameter is not a significant predictor of AF episodes. Is himoto et a l (15) have also rep orteel that there is no correlation between filtered P wave duration and atrial

eniaı·geınent.

In add ition, it has been suspected that the P wave prolongation might be causecl in part by

abnorınalities

in atrial electrical properties such as intraatrial or in teratrial conduction dis turbances or blocks (10,16). On the contrary, so me authors (17,18) reported that left atrial diameter is a significant predictor of AF ep isodes. W e believe that some other changes !ike regression of fibrosis within the wall of the atrium and improvement in disorgan- isecl atrial muscle bund les whic h are not detectable on echocardiographic evaluation after PMBV may be the underlying

mechanisıns

responsible from the decrease in PWD.

A relation between reduced card iac index and

ın­

creased sympathetic activity has been reported in pa- tients with congestive heart failure (19). Therefore, carcliac index appears to be an important

deteııninant

of sympathetic activity. In severe mitral stenosis, as in conges tive heart failure, sy mpathetic act ivity may be increased in association with a reduction in cardi- ac index because of a significant decrease in stroke volume. Several studies have showed increased sym- pathetic activity in pati ents with mitral s tenosis (12,13) . Furthermore, T ükeket aJ(20) reported that in- creased sympathetic activity causes a s ignificant in- crease in PWD. Ashino et aJ(12) have reporteel that increased cardiac index after PMBV causes a signifi- cant decrease in sympathetic activity. As a res ult of this findings, we can suggest that the decrease in PWD measured at first day after PMBV

ınay

be re- lated with the decrease in sympathetic activity be- cause of an increase in cardiac index after PMBV.

In this study, the decrease in maximum P wave dura- tian and PWD after PMBV continued progressively in the fo llow-up measurements at the end of the f irst month and a t sixth month. However there was no corre lation between the decrease in PWD and the

improvement in echocardiographic parameters. The

progressive shortening of PWD in long-term may be exp lained by the regression of the pathological c hanges of the atrial wall w hich results in more ho-

ınogenous

and organized conduction of sinus

iın­

pul ses.

In conclusio n, PWD is significantly higher in pa-

164

tients with mitral stenos is indicating high risk for atrial fibrill ation , than in healthy control s ubjects and it decreas es significantly after PMBV borh in short and long term . When considering the discon- cordance between e lectrocardiographic and echocar- diographic parameters, it can be suggested that there are other factors affecting atrial conduction, to be evaluated in fu rther elinical studies .

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