Significant mitral regurgitation regression by slight modification of the right ventricular pacing site.
ABSTRACT A dual-chamber pacemaker was implanted because of symptomatic bradycardia in a 60-year-old patient free from other heart disease. Then, the patient developed acute congestive heart failure due to pacing-induced mitral regurgitation (MR). Under echocardiographic guidance, modification of location of the right ventricular pacing lead led to a significant decrease in MR severity resulting in immediate clinical improvement.
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ABSTRACT: Conventional activation mapping in the dilated human left ventricle (LV) with left bundle-branch block (LBBB) morphology is incomplete given the limited number of recording sites that may be collected in a reasonable time and given the lack of precision in marking specific anatomic locations. We studied LV activation sequences in 24 patients with heart failure and LBBB QRS morphology with simultaneous application of 3D contact and noncontact mapping during intrinsic rhythm and asynchronous pacing. Approximately one third of the patients with typical LBBB QRS morphology had normal transseptal activation time and a slightly prolonged or near-normal LV endocardial activation time. A "U-shaped" activation wave front was present in 23 patients because of a line of block that was located anteriorly (n=12), laterally (n=8), and inferiorly (n=3). Patients with a lateral line of block had significantly shorter QRS (P<0.003) and transseptal durations (P<0.001) and a longer distance from the LV breakthrough site to line of block (P<0.03). Functional behavior of the line of block was demonstrated by a change in its location during asynchronous ventricular pacing at different sites and cycle lengths. A U-shaped conduction pattern is imposed on the LV activation sequence by a transmural functional line of block located between the LV septum and the lateral wall with a prolonged activation time. Assessment of functional block is facilitated by noncontact mapping, which may be useful for identifying and targeting specific locations that are optimal for successful cardiac resynchronization therapy.Circulation 04/2004; 109(9):1133-9. · 15.20 Impact Factor
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ABSTRACT: We report the case of a 60-year-old patient with preserved ventricular function and no organic mitral leaflet disease implanted with a dual-chamber pacemaker. Right ventricular pacing induced a major ventricular dyssynchrony, a severe mitral regurgitation, and symptoms of congestive heart failure. Upgrading to a biventricular device was associated with a decrease in the symptoms, the ventricular dyssynchrony, and the mitral regurgitation.Europace 10/2007; 9(9):768-9. · 2.77 Impact Factor
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ABSTRACT: We tested the hypothesis that an immediate reduction in mitral regurgitation (MR) after cardiac resynchronization therapy (CRT) results from improved coordinated timing of the papillary muscle insertion sites, using the novel approach of mechanical activation strain mapping. Heart failure patients with left bundle branch block often benefit acutely from CRT; however, the role and mechanism of reduction of MR are unclear. Twenty-six consecutive patients undergoing CRT with at least mild MR were studied (ejection fraction 24 +/- 6%; QRS duration 168 +/- 30 ms). Echocardiographic Doppler and strain imaging was performed immediately before and the day after CRT, as well as in 10 normal control subjects. Mechanical activation sequence maps were constructed using longitudinal strain from 12 basal and mid-LV sites, with color coding of time-to-peak strain. Mitral regurgitation by the volumetric method consistently decreased after CRT: regurgitant volume from 40 +/- 20 ml to 24 +/- 17 ml and regurgitant fraction from 40 +/- 12% to 25 +/- 14% (both: p < 0.001 vs. baseline). Normal controls had uniform segmental time-to-peak strain, with a difference of only 12 +/- 8 ms between all segments. In contrast, CRT patients at baseline had a 106 +/- 74 ms time delay between papillary muscle insertion sites (p < 0.001 vs. normal). This interpapillary muscle time delay shortened after CRT to 39 +/- 43 ms (p < 0.001 vs. baseline) and was significantly correlated with reductions in mitral regurgitant fraction (r = 0.77, p < 0.001). Cardiac resynchronization therapy significantly and immediately reduced MR. Improved coordinated timing of mechanical activation of papillary muscle insertion sites appears to be a mechanistic contributor to immediate MR reduction by CRT.Journal of the American College of Cardiology 11/2004; 44(8):1619-25. · 14.09 Impact Factor