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A critical comparison of echocardiographic measurements used for optimizing cardiac resynchronization therapy: stroke distance is best
Author(s) -
Thomas Dewi E.,
Yousef Zaheer R.,
Fraser Alan G.
Publication year - 2009
Publication title -
european journal of heart failure
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.149
H-Index - 133
eISSN - 1879-0844
pISSN - 1388-9842
DOI - 10.1093/eurjhf/hfp086
Subject(s) - medicine , cardiac resynchronization therapy , ventricular outflow tract , cardiology , reproducibility , doppler echocardiography , heart failure , doppler imaging , ejection fraction , statistics , mathematics , blood pressure , diastole
Aims Dyssynchrony assessment in cardiac resynchronization therapy (CRT) is controversial, and there are no standard protocols for optimizing treatment. We studied the feasibility and reproducibility of several echocardiographic measures to optimize CRT pacemaker settings. We also assessed the utility of ‘stroke distance’ [left ventricular outflow tract velocity–time integral (LVOT VTI)] in performing this function. Methods and results Thirty patients underwent the following functional assessments; 6 min walk test distance, peak VO 2 consumption on cardiopulmonary exercise testing (VO 2 peak), quality‐of‐life scoring, and echocardiography; before and at 3 and 6 months after implantation of the CRT device. At 3 months, patients received LVOT VTI‐guided optimization of interventricular (VV) and atrioventricular (AV) delays. The feasibility and reproducibility of each optimization measurement was statistically analysed, and the functional benefits of optimization examined. Left ventricular outflow tract VTI, interventricular mechanical delay (IVMD), and tissue Doppler lateral‐septal delay showed good feasibility (>90%), whereas LVOT VTI, IVMD, and the 12‐segment tissue Doppler dyssynchrony index showed good reproducibility (coefficient of variation <20%). The most feasible and reproducible measure was LVOT VTI. Our optimization protocol necessitated alteration of AV and/or VV delays in 60% of patients at 3 months and was associated with a 50% improvement in functional responder status between 3 and 6 months. Conclusion Left ventricular outflow tract VTI provides us with a single, direct measure of global LV function which is robust, and easily applicable in routine clinical practice, and which is effective at improving response to CRT.