Demonstration of value of optimizing ECG triggering for cardiovascular magnetic resonance in patients with congenital heart disease

• Main Authors: Knesewitsch Thomas, Meierhofer Christian, Rieger Henrike, Rößler Jürgen, Frank Michael, Martinoff Stefan, Hess John, Stern Heiko, Fratz Sohrab
• Format: Article
• Language: English
• Published: BMC 2013-01-01
• Series: Journal of Cardiovascular Magnetic Resonance
• Subjects: ECG triggering; Congenital heart disease; Blood flow quantification; Vectorcardiography (VCG)
• Online Access: http://www.jcmr-online.com/content/15/1/3

<p>Abstract</p> <p>Background</p> <p>Optimal ECG triggering is of paramount importance for correct blood flow quantification during cardiovascular magnetic resonance (CMR). However, optimal ECG triggering and therefore blood flow quantification is impaired in many patients with congenital heart disease (CHD) due to complex QRS patterns. Therefore, a new ECG-trigger algorithm was developed to address triggering problems due to complex QRS patterns.</p> <p>The aim of this study was to test this new ECG-trigger algorithm in routine patients with CHD and its impact on blood flow quantification.</p> <p>Methods</p> <p>35 consecutive routine patients with CHD undergoing CMR were included in the study. (40% Fallot’s Tetralogy, 20% aortic arch pathology, 14% transposition of the great arteries, 26% others; age 26+/−11 yrs).</p> <p>In all patients, blood flow in the ascending aorta was quantified using the <it>old</it> ECG-trigger algorithm and the <it>new</it> ECG-trigger algorithm in random order. Blood flow quantified using the <it>old</it> or <it>new</it> ECG-trigger algorithm was compared by Bland-Altman analysis.</p> <p>Three blinded investigators evaluated the vector clouds and trigger points of both ECG-trigger methods. Evaluation criteria were false positive and false negative triggered QRS complexes (specificity and sensitivity), and accuracy of detection. Accuracy of detection was defined as time scatter of the trigger around the correct trigger point.</p> <p>Results</p> <p>Specificity, sensitivity, and accuracy of detection significantly increased using the <it>new</it> ECG-trigger algorithm compared to the <it>old</it> ECG-trigger algorithm.</p> <p>Blood flow quantification using the <it>old</it> or <it>new</it> ECG-trigger algorithm differed more than 5% in 31% of the cases.</p> <p>Conclusions</p> <p>Our results suggest that optimizing ECG triggering during CMR using our new algorithm can avoid errors of >5% in approximately 1/3 of routine patients with congenital heart disease (CHD). We furthermore suggest that incorrect ECG triggering appears to be problematic for blood flow quantification of many patients with CHD undergoing routine CMR.</p>