Interventricular Mechanical Dyssynchrony: Quantification with Velocity-encoded MR Imaging

Radiology. 2009; 253(2):364-371

Muellerleile K, Baholli L, Groth M, Barmeyer AA, Koopmann K, Ventura R, Koester R, Adam G, Willems S, Lund GK

OBJECTIVES: To evaluate the performance of velocity-encoded (VENC) magnetic resonance (MR) imaging, as compared with pulsed-wave echocardiography (PW-ECHO), in the quantification of interventricular mechanical dyssynchrony (IVMD) as a predictor of response to cardiac resynchronization therapy (CRT).

METHODS:  The study was approved by the local ethics committee, and all patients provided written informed consent. The study involved the examination of 45 patients (nine women, 36 men; median age, 60 years; interquartile age range, 47–69 years) with New York Heart Association class 2.0–3.0 heart failure and a reduced left ventricular ejection fraction (median, 25%; interquartile range, 21%–32%), with (n = 25) or without (n = 20) left bundle branch block. Aortic and pulmonary flow curves were constructed by using VENC MR imaging and PW-ECHO. IVMD was defined as the difference between the onset of aortic flow and the onset of pulmonary flow. Intraclass correlation coefficient, Spearman correlation coefficient, Bland-Altman, and Cohen κ analyses were used to assess agreement between observers and methods.

RESULTS: Inter- and intraobserver agreement regarding VENC MR imaging IVMD measurements was very good (intraclass r = 0.96, P < .001; mean bias, −3 msec ± 11 [standard deviation] and 0 msec ± 10, respectively). A strong correlation (Spearman r = 0.92, P < .001) and strong agreement (mean difference, −6 msec ± 16) were found between VENC MR imaging and PW-ECHO in the quantification of IVMD. Agreement between VENC MR imaging and PW-ECHO in the identification of potential responders to CRT was excellent (Cohen κ = 0.94).

CONCLUSIONS: VENC MR measurements of IVMD are equivalent to PW-ECHO measurements and can be used to identify potential responders to CRT.

PMID: 19703849

2 Responses

  1. Jacobo Kirsch, MD  on November 23rd, 2009

    Another interesting use for MRI! The authors showed almost perfect agreement between VENC MR imaging and PW-ECHO, to identify potential responders to CRT. But, what is the added value of MRI in these populations? Myocardial fibrosis as assessed by delayed enhancement?

  2. David N. Kenigsberg, MD, FACC  on November 24th, 2009

    I read the article with interest. The issue however is as follows. Imaging to determine dyssynchrony has been fraught with error. There are been much inter observer variability and many methods to determine dyssynchrony with no consensus. In addition, an ECG is a more sensitive and specific measurement of responders to CRT than dyssynchrony. So at the end of the day, we use ECG (QRS duration > 120 ms, and the longer the better).


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