Potential Candidates for Cardiac Resynchronization Therapy in Japanese Patients With Idiopathic Dilated Cardiomyopathy-A Niigata Multicenter Study of DCM-

Review of eligibility for cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) is underused. Recent guidelines have expanded indications for CRT to include less severe symptoms but now favor left bundle branch block morphology in patients with moderate QRS prolongation. The prevalence of CRT eligibility according to historical and current guidelines is uncertain. The aim of this review was to identify and synthesize all existing published research reporting the prevalence of CRT eligibility. A systematic review of electronic databases including MEDLINE, Embase, and the Cochrane Library was performed. The primary outcome was the proportion of patients eligible for CRT according to historical and current criteria. Secondary outcomes included the individual components of eligibility (the ejection fraction, symptoms, and QRS duration and morphology). Eligibility estimates were pooled using random-effects models because of marked heterogeneity in between-study variance. Thirty studies were identified. No study used current guideline criteria. On the basis of historical criteria, 11 ± 3% of ambulatory and 9 ± 3% of hospitalized patients are eligible for CRT. However, New York Heart Association class II in current guidelines is at least as frequent as New York Heart Association III or IV. Approximately 1/3 of patients have QRS prolongation, 2/3 of whom have left bundle branch block. Only a few patients have non-left bundle branch block with QRS duration <150 ms. Medical contraindication or ineligibility was rarely assessed. In conclusion, current estimates of need are outdated. Inclusion of milder symptoms potentially doubles the eligible population. Studies in unselected cohorts are needed to accurately define the individual components of eligibility, together with the prevalence and reasons for ineligibility.

Reverse perfusion-metabolism mismatch predicts good prognosis in patients undergoing cardiac resynchronization therapy: a pilot study

BACKGROUND

Cardiac resynchronization therapy (CRT) improves glucose metabolism in the septum of patients with heart failure, so in the present study the predictive value of combined fluorodeoxyglucose (FDG)-positron emission tomography (PET) and metoxy-isobutyl isonitrile (MIBI)-single photon emission computed tomography (SPECT) for the prognosis of patients undergoing CRT was investigated.

METHODS AND RESULTS

Fourteen patients (70.3+/-8.2 years) who underwent FDG-PET and MIBI-SPECT before implantation of a biventricular pacemaker were enrolled. The total number of matches, mismatches, reverse mismatches, summed difference score (SDS: sum total of FDG - MIBI scores) and SDS per segment (%SDS) in each of 5 areas of myocardium (septum, anterior, lateral, inferior area, apex) was calculated and compared between the survival groups (all survival: survival group; survival without ischemic heart disease (IHD): non-IHD survival group) and non-survival group. Both the number of reverse mismatch segments and the %SDS in the septum in the non-IHD survival group were significantly greater than in the non-survival group (3.2+/-1.6 vs 0.5+/-0.6, p<0.05; 0.62+/-0.61 vs -0.11+/-0.19, p<0.05). The receiver-operating characteristics curves for prognosis showed that the area under the curve for the number of reverse mismatch segments in the septum (0.93; confidence interval 0.61-0.98) was significantly greater.

CONCLUSION

A reverse mismatch pattern in the septum can predict a good prognosis for patients treated with CRT.