Sonuç ve Öneriler

Sonuç olarak yaptığımız çalışma, literatürde AVNRT olgularında PA-TDI intervali ile hesaplanan total atriyal ileti zamanının ve sol atriyum çap, alan, volüm, mekanik – fazik fonksiyonların bir arada değerlendirildiği ilk çalışma olma özelliğine sahiptir.

Bulgulara baktığımızda; AVNRT grubu ile kontrol grubu arasında sol atriyum çap, alan, volüm ve mekanik – fazik fonksiyonlar açısından anlamlı farklılık saptanmaz iken, PA-TDI intervalinin AVNRT grubunda anlamlı şekilde daha uzun olduğu bulunmuştur. Bu durum AVNRT olgularında, konvansiyonel ekokardiyografi yöntemleri ile saptanabilen yapısal sol atriyum değişiklikleri oluşmadan önce doku düzeyinde yeniden şekillenmenin başladığını ve varolduğunu düşündürmektedir. Sol atriyum miyokardında yapısal değişiklikler oluşmadan önce elektriksel yeniden şekillenmenin başlaması ve buna bağlı olarak heterojen sol atriyal

miyokardiyal dokunun oluşması muhtemel görünmektedir. Oluşan heterojen sol atriyum miyokard dokusu aritmojenik substrat görevi görerek, reentrant mekanizmalar yolu ile aritminin başlamasını ve devamını sağlıyor olabilir.

Bu sonuçlar ışığında çalışmamızın bu konudaki literatüre katkı sağladığını düşünmekteyiz. Bu çalışma, bu konuda yapılan ilk ve küçük bir çalışmadır. Çalışmamıza dahil edilen olgu sayısının az olduğu ve diğer kısıtlılık nedenleri göz önüne alındığında daha büyük kohortları içeren başka çalışmalarla desteklenmesi gerekmektedir.

5. ÖZET

Giriş ve Amaç: Atriyoventriküler nodal reentrant taşikardi (AVNRT) en sık görülen düzenli,

paroksismal supraventriküler aritmidir. Literatürde AVNRT hastalarında sol atriyumun mekanik – fazik fonksiyonlarını ve total atriyal ileti zamanını birlikte değerlendiren çalışma mevcut değildir. Çalışmamızın amacı; AVNRT’nin sol atriyum mekanik – fazik fonksiyonlarına ve total atriyal ileti zamanına olan etkisini araştırmaktır.

Gereç ve Yöntem: Çalışmaya 30 AVNRT olgusu (ortalama yaş: 44 ± 12, 24 kadın) ile yaş ve

cinsiyet açısından eşleştirilmiş 31 kontrol olgusu dahil edildi. Tüm olguların bazal klinik özellikleri, elektrokardiyografik verileri, standart ekokardiyografik inceleme sonuçları kaydedildi. Ekokardiyografik incelemede ek olarak sol atriyumun mekanik – fazik

fonksiyonları ve total atriyal ileti zamanı değerlendirildi. Total atriyal ileti zamanı; yüzey EKG’de P dalga başlangıcından doku Doppler görüntülemede geç diyastolik A dalgası pikine kadar geçen süre olarak belirlendi ve lateral PA-TDI intervali olarak isimlendirildi. AVNRT ve kontrol grubu verileri uygun istatistiksel analizler sonrası karşılaştırmalı olarak değerlendirildi.

Bulgular: AVNRT hastalarında; hem sol atriyum lateral duvarından ölçülen (lateral PA-TDI

intervali) total atriyal ileti zamanı, hem de interatriyal septum apikalinden ölçülen (septal PA-TDI intervali) atriyal ileti zamanı kontrol grubuna göre anlamlı olarak yüksek bulundu (lateral PA-TDI intervali için sırasıyla 120.9 ± 13.3 msn.’e karşı 105 ± 12.6 msn, p<0.001 ve septal PA-TDI intervali için sırasıyla 102.4 ± 13.4 msn.’e karşı 88.5 ± 12.5 msn, p<0.001). Gruplar arasında sol atriyum çap, alan, volüm, volüm indeksi ve mekanik – fazik fonksiyonlar açısından anlamlı farklılık saptanmadı.

Lateral PA-TDI intervalinin, septal PA-TDI intervali ile yakın korelasyon gösterdiği (r=0.876, p<0.001) ancak yüzey EKG’de ölçülen P dalga süresi ve P dalga amplitüdü ile korelasyon göstermediği saptandı (sırasıyla r=0.063, p=0.652 ve r=-0.123, p=0.381). Yapılan ROC analizinde; lateral PA-TDI intervalinin 105 msn. kestirim değerinde % 90 duyarlılık, %48 özgüllük (eğri altında kalan alan=0.784, % 95-GA=0.666 – 0.902, P<0.001) değeri ve septal PA-TDI intervalinin 92 msn. kestirim değerinde % 90 duyarlılık, %58 özgüllük (eğri altında kalan alan=0.777, %95-GA=0.660 – 0.894, P<0.001) değeri ile tanısal olduğu görüldü.

Sonuç ve Tartışma: AVNRT grubu ile kontrol grubu arasında sol atriyum çap, alan, volüm

ve mekanik – fazik fonksiyonlar açısından anlamlı farklılık saptanmaz iken, PA-TDI intervalinin AVNRT grubunda anlamlı şekilde daha uzun olduğu bulunmuştur. Bu durum

AVNRT olgularında, konvansiyonel ekokardiyografi yöntemleri ile saptanabilen yapısal sol atriyum değişiklikleri oluşmadan önce doku düzeyinde yeniden şekillenmenin başladığını ve varolduğunu düşündürmektedir. Sol atriyum miyokardında yapısal değişiklikler oluşmadan önce elektriksel yeniden şekillenmenin başlaması ve buna bağlı olarak heterojen sol atriyal miyokardiyal dokunun oluşması muhtemel görünmektedir. Oluşan heterojen sol atriyum miyokard dokusu aritmojenik substrat görevi görerek, reentrant mekanizmalar yolu ile aritminin başlamasını ve devamını sağlıyor olabilir. Çalışmamıza dahil edilen olgu sayısının az olduğu ve diğer kısıtlılık nedenleri göz önüne alındığında daha büyük kohortları içeren başka çalışmalarla desteklenmesi gerekmektedir.

Anahtar Kelimeler: Atriyoventriküler nodal reentrant taşikardi, doku Doppler görüntüleme,

PA-TDI intervali, sol atriyum mekanik fazik fonksiyonları, total atriyal ileti zamanı.

6. ABSTRACT

BACKGROUND: Atrioventricular Nodal Reentrant Tachicardia (AVNRT) is the most

common regular, paroxismal supraventricular arrythmia. In medical literature there is no study evaluating left atrium (LA) mechanical, phasic functions and total atrial conduction time (TACT) together. The aim of this study is to investigate the affects of AVNRT over LA mechanical, phasic functions and TACT.

MATERIALS AND METHODS: 30 AVNRT patients (median age 44 ± 12, 24 female) and

age and sex matched 31 control cases were included in the study. Basal characteristics, electrocardiographic datas and standard echocardiographic evaluation results of all patients were recorded. In addition to standard measurements, in echocardiographic evaluation LA mechanical and phasic functions and TACT were obtained. TACT was defined as the time

delay between the onset of the P-wave of the surface electrocardiogram and the peak A'-wave on the tissue Doppler imaging (TDI) tracing of the left atrial lateral wall which is also called lateral PA-TDI interval. AVNRT and control group datas were evaluated comparatively after proper statistical analyses were done.

RESULTS: In AVNRT patients; lateral PA-TDI interval which is defined as TACT measured

from LA lateral wall and septal PA-TDI interval which is defined as ACT measured from apical area of the interatrial septum were statictically higher than control patients (For lateral PA-TDI interval 120.9 ± 13.3 msn. over 105 ± 12.6 msn, p<0.001 and for septal PA- TDI interval 102.4 ± 13.4 msn. over 88.5 ± 12.5 msn, p<0.001, respectively.) There were no statictically significant difference between groups according to LA diameter, area, volume, volume index and mechanical- phasic functions.

Lateral PA-TDI interval were found to be closely correlated with septal PA-TDI interval (r=0.876, p< 0.001); and not correlated with P wave duration and P wave amplitude obtained from the surface electrocardiogram (r=0.063, p=0.652 ve r=-0.123, p=0.381 respectively). In the ROC analysis lateral PA-TDI predictive value of 105 msn. were found to be diagnostic with 90 % sensitivity and 48 % specificity (Area under curve=0.784, 95 % CI=0.666 – 0.902, P<0.001) while the septal PA-TDI predictive value of 92 msn. were found to be diagnostic with 90 % sensitivity and 58 % specificity (Area under curve=0.777, 95 %-CI=0.660 – 0.894, P<0.001).

CONCLUSION AND DISCUSSION: Between AVNRT and control group LA diameter,

area, volume, mechanical and phasic functions didn’t differ significantly. On the other hand PA-TDI interval of AVNRT patients were signficantly higher than control group. This finding leads us to the idea of before structural changes which can be stated with conventional echocardiographic methods, left atrial remodelling in tissue level can exist in AVNRT

patients. Before structural changes has developed in left atrial myocardium, electrical remodelling and myocardial heterogenicity according to electrical remodelling is possible to occur. That heterogenic left atrial myocardium works as an arryhtmogenic substrate for reentrant mechanisms of tachicardia. Due to the small patient cohort and other restrictions of our study , larger studies are needed to support our findings.

KEY WORDS: Atrioventricular nodal reentrant tachicardia, tissue doppler imaging, PA-TDI

interval, left atrium mechanical phasic functions, total atrial conduction time

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