HUBUNGAN RASIO Tp-Te/QT DENGAN KEJADIAN VENTRICULAR TACHYCARDIA PADA PASIEN IDIOPATHIC OUTFLOW TRACT VENTRICULAR PREMATURE CONTRACTION

ARINA P. NUGRAHENI, dr. Erika Maharani, Sp.JP(K).; dr. Irsad Andi Arso, Sp.PD, Sp.JP(K).

2017 | Tesis-Spesialis | SP KARDIOLOGI DAN KEDOKTERAN VASKULAR

Latar Belakang : Idiopathic outflow tract VPC dapat berubah menjadi VT (ventricular tachycardia) melalui mekanisme triggered activity. Dispersi repolarisasi transmural (DRT) terjadi karena sel M (Masonic midmyocardial Moe) memiliki durasi potensial aksi yang berbeda dan dapat berperan sebagai substrat fungsional serta rentan terjadinya EAD fase 2. Rasio Tp-Te/QT merupakan indeks aritmogenesis telah dilaporkan berkaitan dengan kejadian ventricular arrhythmia. Penelitian ini bertujuan untuk melihat hubungan antara rasio Tp-Te/QT dengan kejadian VT pada penderita idiopathic outflow tract VPC. Metode Penelitian : Penelitian observasional analitik dengan desain penelitian potong lintang dengan data retrospektif dari populasi terjangkau di RSUP Dr. Sardjito dari bulan September sampai Oktober 2017. Data EKG (elektrokardiogram), TMT (treadmill test), monitor Holter dan studi elektrofisiologi ditelusur. Pengukuran rasio Tp-Te/QT dilakukan di sandapan V4, V5 dan V6 oleh pengamat tunggal serta dibagi menjadi rasio meningkat (>0.25) dan normal (<0.25). Uji diagnostik dengan Chi Square dipakai untuk menganalisis RP (rasio prevalensi) dan regresi logistik untuk uji multivariat. Hasil : Dari total 46 pasien, terdapat 28 subjek yang mengalami VT dan 18 subjek yang hanya mengalami VPC. Rasio Tp-Te/QT sandapan V4 yang meningkat didapatkan pada 11 pasien, sandapan V5 dan V6 masing-masing sebanyak 13 pasien. Rasio prevalensi rasio Tp-Te/QT sandapan V4 terhadap kejadian VT adalah sebesar 2.059 (CI 95%: 1.464-2.895; p=0.007), sandapan V5 dan V6 sebesar 2.200 (CI 95%: 1.514-3.197; p=0.002). Rasio Tp-Te/QT di sandapan V4, V5 dan V6 tidak signifikan berbeda dan sama kuat dalam membedakan kejadian VT (p<0.001; CI 95%). Penyesuain faktor perancu dengan uji multivariat memberikan hasil yang tidak signifikan (RP : 1.290; CI 95%: 0.444-3.747; p=0.639). Simpulan : Rasio Tp-Te/QT yang meningkat pada idiopathic outflow tract VPC memiliki rasio prevalensi untuk kejadian VT yang lebih tinggi dibandingkan dengan rasio Tp-Te/QT yang normal tetapi bersifat tidak independen karena dipengaruhi oleh faktor hipertensi. Sandapan V4, V5 dan V6 dapat digunakan sama kuat dalam membedakan idiopathic outflow tract VPC yang mengalami VT dan yang tidak mengalami VT.

Background: Idiopathic outflow tract VPC can turn into VT (ventricular tachycardia) through triggered activity mechanism. Transmural dispersion of repolarization (TDR) occurs due to M (Masonic midmyocardial Moe) cell possesing different action potential duration, can serve as functional substrate and is susceptible to EAD phase 2. The Tp-Te / QT ratio is an arrhythmogenesis index and has been reported to be associated with the incidence of ventricular arrhythmia . This study aims to see the relationship between the ratio of Tp-Te / QT with the incidence of VT in idiopathic outflow tract VPC. Research Methods: Analytical observational research with cross sectional design was done. Data were retrospectively retrieved from the population in Dr. Sardjito from September to October 2017. Electrocardiogram (ECG), TMT (treadmill test), Holter monitor and electrophysiology study data searching were done. The measurement of the Tp-Te/QT ratio is performed in the V4, V5 and V6 rays by a single observer. The ratio of Tp-Te/QT in divided ratio increased (>0.25) and normal (<0.25). Diagnostic tests with Chi Square were used to analyze PR (prevalence ratio), whereas logistic regression was performed for multivariate test. Results: From the total of 46 patients, there were 28 subjects who had VT and 18 subjects who experienced VPC. Increased Tp-Te/QT ratios of lead V4 were obtained in 11 patients, V5 and V6 were 13 patients each. The prevalence ratio of Tp-Te/QT ratios to VT incidence in V4 was 2.059 (95% CI: 1.464-2.895; p = 0.007), while the V5 and V6 were slightly higher 2,200 (95% CI: 1.514-3.197; p =0.002) . Tp-Te/QT ratio in lead V4, V5 and V6 are not significantly different and equally strong in distinguishing VT events (p <0.001; 95% CI). Adjustment of confounding factor with multivariate test gave insignificant results (RP: 1.290; 95%. Conclusions: Idiopathic outflow tract VPC patients with increased Tp-Te/QT ratio did not have higher prevalence ratio of VT compared with idiopathic outflow tract VPC patients with normal Tp-Te/QT ratio.

Kata Kunci : Tp-Te/QT, idiopathic outflow tract ventricular arrhythmia, VPC, VT, Tp-Te/QT, idiopathic outflow tract ventricular arrhythmia