Predictors of atrial arrhythmias in patients with mitral valve prolapse

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Mitral valve prolapse (MVP) is the most common cardiac valvular abnormality in industrialized coun- tries and the leading cause of mitral valve surgery.
92995_ActaCardio_64-6_07_09-3888

11-12-2009

Acta Cardiol 2009; 64(6): 755-760

11:43

Pagina 755

doi: 10.2143/AC.64.6.2044739

755

Predictors of atrial arrhythmias in patients with mitral valve prolapse

Yasin TURKER1, MD; Mehmet OZAYDIN2, MD; Gurkan ACAR3, MD; Mustafa OZGUL4, MD; Yesim HOSCAN5, MD; Ercan VAROL2, MD; Abdullah DOGAN2, MD; Dogan ERDOGAN2, MD 1Gulkent

State Hospital, Isparta; 2Department of Cardiology, School of Medicine, Suleyman Demirel University, Isparta; 3Department of Cardiology, School of Medicine, Sutcu Imam University, Kahramanmaras; 4Medical Park Hospital, Van; 5Department of Cardiology, School of Medicine, Baskent University, Alanya, Turkey. Objective — Arrhythmias have been reported to occur frequently in symptomatic patients with mitral valve prolapse (MVP). The mechanisms causing atrial arrhythmias in patients with MVP have not been fully investigated. The purpose of this study was to determine the clinical, echocardiographic and heart rate variability parameters, and plasma concentrations of electrolytes and inflammatory markers in predicting atrial arrhythmias in patients with MVP. Methods — A total of 58 consecutive patients with MVP were included in this study. We performed electrocardiography, echocardiography, Holter analysis, routine biochemical tests including plasma concentrations of electrolytes and inflammatory markers, and evaluated the clinical characteristics. Atrial arrhythmia was defined as occurrence of any of the following: atrial premature contractions, atrial couplets, supraventricular tachycardia, atrial flutter or fibrillation documented by Holter analysis, continuous monitoring or by electrocardiography. Results — Twenty-eight patients (48%) had atrial arrhythmias, and 30 (52%) patients had no atrial arrhythmias. Univariable predictors of atrial arrhythmias included isovolumetric relaxation time, lateral systolic (S’), lateral late diastolic (A’), septal A’ Doppler velocities, anterior mitral leaflet thickness, anterior mitral leaflet thickness of > 5∞∞mm, posterior mitral leaflet thickness and the occurrence of moderate to severe mitral regurgitation. Multivariable logistic regression analysis showed that occurrence of moderate to severe mitral regurgitation was the only independent predictor of atrial arrhythmias (relative risk: 2.4, 95% confidence interval 1.32-4.86, P =∞∞0.005). Conclusions — The present study showed that the only independent predictor of atrial arrhythmias in patients with MVP is the occurrence of moderate to severe mitral regurgitation. Keywords: Mitral valve prolapse – atrial arrhythmias.

Introduction Mitral valve prolapse (MVP) is the most common cardiac valvular abnormality in industrialized countries and the leading cause of mitral valve surgery for isolated mitral regurgitation1,2. MVP is generally understood to be the systolic displacement of an abnormally thickened, redundant mitral leaflet into the left atrium during systole3. Its prevalence has been estimated around 2.4%, ranging from 2% to 4%4,5.

Address for correspondence: Dr. Yasin Turker, Iskender M. 2005 C. Dogan Apt. No: 2/7, 32100 Isparta, Turkey. E-mail: dryasinturker@ hotmail.com Received 10 August 2009; accepted for publication 18 September 2009.

Arrhythmias have been reported to occur frequently in symptomatic patients with MVP6-9. There is evidence that arrhythmic complications are not infrequent and that the risk of sudden death is increased among patients with MVP6,8,10,11. Zuppiroli et al., showed that atrial arrhythmias correlated with age, female gender, presence of mitral regurgitation, left ventricular and left atrial diameter and anterior mitral leaflet thickness in patients with MVP6. The mechanisms causing atrial arrhythmias in patients with MVP have not been fully investigated. The purpose of this study was to determine the clinical, echocardiographic and heart rate variability (HRV) parameters, and plasma concentrations of electrolytes and inflammatory markers in predicting atrial arrhythmias in patients with MVP.

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Methods PATIENTS A total of 65 consecutive patients with MVP were evaluated in our centre. Exclusion criteria included ischaemic or rheumatic heart disease, severe left ventricular dysfunction, patients with Marfan syndrome and congenital heart disease. Of the 65∞∞patients evaluated, 7 were excluded because of rheumatic heart disease (n∞∞=∞ 6) or Marfan syndrome (n∞∞=∞ 1). Therefore, the population of this study consisted of 58∞∞patients (32 women; mean age 33∞∞±∞ 11∞∞years, range 16 to 68∞∞years) with MVP. We performed electrocardiography, echocardiography, Holter analysis, routine biochemical tests including plasma concentrations of electrolytes and inflammatory markers, and evaluated the clinical characteristics. The clinical variables were age, gender, history of hypertension, smoking, diabetes mellitus and hypercholesterolaemia. Atrial arrhythmia was defined as occurrence of any of the following: atrial premature contractions, atrial couplets, supraventricular tachycardia, atrial flutter or fibrillation documented by Holter analysis, continuous monitoring or by electrocardiography.

ECHOCARDIOGRAPHY In all subjects, transthoracic M-mode, two-dimensional, pulsed-wave, continuous-wave, colour and tissue Doppler echocardiographic examinations were performed using a Vingmed System V echocardiographic system (General Electric Vingmed Ultrasound, Horten, Norway), using 2.5-3.5∞∞MHz transducers. Left ventricular end-diastolic and end-systolic diameters and left atrial diameters were determined from 2D images, according to published criteria12. Left ventricular ejection fraction (EF) was calculated by using the modified Simpson’s method. Peak early (E) and late (A) transmitral filling velocities, E/A ratio, deceleration time of E velocity were measured from mitral inflow velocities. Isovolumetric relaxation time (IVRT) was measured from the end of the systolic (S) wave to the beginning of the E. Tissue Doppler was applied in the pulsed Doppler mode to record mitral annulus velocities at septal and lateral corners, and afterwards measurements were averaged. Systolic (S’), early diastolic (E’), and late diastolic (A’) tissue Doppler velocities were measured. The displacement of each leaflet was measured in the parasternal long-axis view above a line connecting the mid portions of the annular hinge points13. The thickness of the mitral valve was measured by M mode recording. Each leaflet was measured, and maximal thickness was used for categorization. A measurement of ≥ 5∞∞mm identified a thickened leaflet14. The degree of mitral regurgitation

was assessed by the method recommended by the current guidelines15. Each echocardiogram was evaluated by two experienced cardiologists.

HOLTER

ANALYSIS

The 24-hour Holter recording was performed with the SCHILLER MT-200∞∞system (Schiller AG, Baar, Switzerland) and independently analysed by two cardiologists. Recordings were analysed for arrhythmias and HRV. Atrial arrhythmias were defined as occurrence of any of the following: atrial premature contractions, atrial couplets, atrial tachycardia, atrial flutter or fibrillation. The HRV analysis was performed in time domains according to the Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology indices were analysed16. The following time-domain parameters were calculated: mean RR intervals, standard deviations of all NN intervals (SDNN) and standard deviations of the averages of NN (SDANN).

BIOCHEMICAL

ANALYSIS

Blood samples were drawn at initial presentation from the ‘antecubital’ vein. Whole blood count and routine biochemical tests including serum levels of electrolytes were performed. Blood samples were drawn to measure the serum level of high-sensitivity C-reactive protein (hsCRP) and they were stored at -80°C in a deepfreezer. HsCRP was assayed by the immunoturbidimetric method using an Abbot Aeroset Automated Instrumented Analyzer (Abbot Laboratories Abbot Park IL 60064) in serum samples according to the manufacturer’s protocol. HsCRP concentrations were determined with a detection limit of ~0.005∞∞mg/dl.

STATISTICAL

ANALYSIS

Categorical variables were compared with the chisquare test. Continuous variables were expressed as mean ± SD and categorical variables were presented as percentages. Continuous variables were compared with the Student t test for normally distributed values and with the Mann-Whitney U test for abnormally distributed values. Univariable logistic regression analysis was performed to evaluate the relation between the atrial arrhythmias and variables. Variables with a P value of∞∞