Improved survival of idiopathic dilated cardiomyopathy in the 1990s

N-terminal prohormone brain natriuretic peptide plasma levels in heart failure are affected both directly and indirectly by carvedilol

N-terminal prohormone brain natriuretic peptide (NT Pro BNP) is a sensitive marker of left ventricular function in patients with heart failure. The influence of carvedilol on NT Pro BNP plasma levels was analyzed in 21 heart failure patients. Blood samples were taken before administration and after 12 months of treatment with low-dose carvedilol. Peak oxygen consumption did not change after carvedilol treatment, left ventricular ejection fraction improved (P < .005) in 11 patients (52%), did not change in 9 (43%), and decreased in 1 (5%). In patients where left ventricular ejection fraction improved, NT Pro BNP tended to decrease; however, in patients without improvement, NT Pro BNP increased at follow-up. A correlation exists between magnitude of change in BNP and magnitude of improvement in ventricular function during carvedilol therapy. Patients without noticeable changes in left ventricular ejection fraction with a low to moderate carvedilol dosage show an increase in NT Pro BNP plasma levels.

Prolonged QRS duration and severity of mitral regurgitation are unfavorable prognostic markers of heart failure in patients with nonischemic dilated cardiomyopathy

BACKGROUND

The goal of the present study was to identify predictors of event-free survival in nonischemic dilated cardiomyopathy (NIDCM) patients after administration of angiotensin-converting enzyme inhibitors (ACEI)/angiotensin receptor blockers (ARB) and beta-blockers.

METHODS AND RESULTS

The study group comprised 78 consecutive patients with NIDCM between 1997 and 2002. NIDCM was defined as ejection fraction (EF) <0.40 and left ventricular end-diastolic diameter (LVEDD) >55 mm on echocardiography and normal coronary angiography. The mean EF and LVEDD was 26.3 +/- 10.5%, and 62.9 +/- 7.1 mm, respectively. Patients were treated with optimal medical therapy including ACEI/ARBs and/or beta-blockers and followed up for 35.6 +/- 27.8 months. The primary endpoint was either cardiac death or hospitalization because of deterioration of heart failure. Cox's regression analysis was used to establish the association of age, sex, EF, LVEDD, left atrial diameter, cardiac index, pulmonary capillary wedge pressure, QRS duration, severity of mitral regurgitation, body mass index, New York Heart Association class and the presence of atrial fibrillation with these events. During follow-up, 23 patients reached the primary endpoint. In a multivariate analysis, EF (chi-square 5.74, p=0.0166), severity of mitral regurgitation (chi-square 12.31, p=0.0004), and QRS duration (chi-square 11.20, p=0.0008) remained significant predictors.

CONCLUSION

In NIDCM patients, prolonged QRS duration is a high risk factor for remodeling and unfavorable events. The severity of mitral regurgitation was also a strong risk predictor.

Long-Term Prognosis of Dilated Cardiomyopathy Revisited An Improvement in Survival Over the Past 20 Years

BACKGROUND

Because of their favorable prognostic effects, angiotensin converting enzyme inhibitors (ACEI), angiotensin II receptor blockers (ARB) and beta blockers have become background therapy in dilated cardiomyopathy (DCM). However, there are few reports concerning the long-term prognosis of Japanese patients with DCM in relation to these treatments.

METHODS AND RESULTS

One hundred and fifty patients with DCM were divided into 2 groups: group A (n=46) (diagnosis: 1982-1989) and group B (n=104) (diagnosis: 1990-2002). During follow-up period of 6.9+/-4.8 years, 62 patients died and 1 patient had a heart transplant. The survival rate at 5 and 10 years was 60.9% and 34.8%, respectively, in group A patients, and 80.9% and 65.3%, respectively, in group B patients (p=0.0079). In group A patients, ACEI/ARB or beta blockers were less frequently used (p<0.0001), whereas antiarrhythmics (class Ia or Ib) were more often used (p<0.0001). The patients treated with ACEI/ARB and beta blockers showed a better survival rate than those without (p<0.0001). The patients with antiarrhythmics showed a worse survival rate than those without (p<0.0001).

CONCLUSION

The prognosis of Japanese patients with DCM has significantly improved over the past 20 years. This improvement may be explained partly through the increased use of ACEI/ARB and beta blockers and a declining use of antiarrhythmics.

Suppressive effect of the Gly389 allele of the beta1-adrenergic receptor gene on the occurrence of ventricular tachycardia in dilated cardiomyopathy

Beta-1-adrenergic receptor (beta1-AR) blockers reduce both the incidence of sudden death and the ventricular volume in heart failure. In vitro, the Gly389 variant of beta1-AR mediates less adenylyl cyclase activities than the Arg389 variant, so Arg389Gly polymorphism was investigated with regard to the genesis, progression, or arrhythmogenesis of dilated cardiomyopathy (DCM). Allele and genotype frequencies of the Arg389Gly polymorphism were determined in 163 DCM patients and 157 age- and sex-matched controls. There were no differences in genotype and allele frequencies between patients and controls. Echocardiograms, left ventriculograms and 24h-Holter electrocardiograms were evaluated in the DCM patients and none of the clinical indices, other than ventricular tachycardia (VT), differed among the 3 genotypes. The Gly389 allele was more frequent in the VT(-) group than in the VT(+) group (0.46 vs 0.24, p=0.001). In univariate analysis, the odds ratio for VT in patients carrying 1 or 2 copies of the Gly389 allele was 0.29 ([95% confidence interval, 0.13-0.64], p=0.002), when compared with the Arg389 homozygotes. The Gly389 variant supressed the occurrence of VT in DCM, suggesting that this allele confers a decreased risk of sudden death.

Long-term prognosis of patients with mildly dilated cardiomyopathy

The long-term prognosis of patients with mildly dilated cardiomyopathy (MDCM) was investigated in 21 patients. MDCM was defined as left ventricular ejection fraction < or = 40% and left ventricular end-diastolic volume < or = 120 ml/m2 by left ventriculography. During a follow-up period of 6.8+/-3.7 years, there were 9 cardiac events (5 heart failure deaths, 2 sudden deaths, and 2 re-hospitalizations for heart failure). Only in the patients without cardiac events was there a significant decrease in left ventricular size (end-diastolic dimension decreased from 58+/-6 mm to 50+/-8 mm, p<0.001) and an improvement in systolic function (fractional shortening increased from 17+/-5% to 26+/-11%, p=0.007). However, left atrial dilation was observed in the patients with an event (from 39+/-5 mm to 43+/-5 mm, p=0.02). Based on proportional hazard analysis, left ventricular end-diastolic pressure and mean pulmonary artery pressure at diagnosis and left atrial dimension at the time of follow-up were significant predictors of poor outcome. A subset of patients with MDCM has impaired hemodynamics at diagnosis, left atrial dilation at follow-up and a poor prognosis, and must be followed carefully even if the left ventricular dilatation is mild.

Comparative left ventricular functional and neurohumoral effects of chronic treatment with carvedilol versus metoprolol in patients with dilated cardiomyopathy

The efficacy of treating dilated cardiomyopathy with metoprolol was compared with that of carvedilol. Metoprolol was administered to 29 patients, and carvedilol to 62. Patients who could not be dosed with up to 40 mg daily of metoprolol or 20 mg daily of carvedilol were defined as intolerant. As well as the tolerability of these beta-blockers, the effects on left ventricular end-diastolic dimension (LVDd), fractional shortening (FS), plasma atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) concentrations, the delayed heart and mediastinum (H/M) ratio determined from metaiodobenzylguanidine imaging were compared. Drug intolerance occurred in 24% of patients in the metoprolol group and 19% in the carvedilol group. Among the drug-tolerant patients, LVDd, FS and plasma BNP concentration improved in both groups and to the same degree. Only 25% of drug-tolerant patients in the metoprolol group had a delayed H/M ratio below 1.9 compared with 57% in the carvedilol group. Both metoprolol and carvedilol, when tolerated, improve cardiac function and neurohumoral factors to the same degree. However, carvedilol is preferable to metoprolol for patients with a low delayed H/M ratio.

Changes in the occurrence of mechanical alternans after long-term beta-blocker therapy in patients with chronic heart failure

Mechanical alternans has been observed in patients with severe congestive heart failure, and the phenomenon is considered to be a terminal sign. Therapeutic strategies for chronic heart failure have significantly developed, but it is uncertain whether patients with mechanical alternans can be effectively treated or not. Seventeen consecutive patients with dilated cardiomyopathy were enrolled: 11 were treated with beta-blockers on conventional therapeutic regimens and 6 patients were not indicated for or were unable to continue beta-blockade. Mechanical alternans was detected during cardiac catheterization in the patients under physiologic tachycardia (110 beats/min) and stepwise dobutamine loading. In the initial study, mechanical alternans occurred in 70.6% of the patients: 8 of the 11 being treated with beta-blockers and 4 of the 6 without beta-blockade therapy. In the second study, none of the patients taking beta-blockers showed mechanical alternans under the same protocol; the occurrence of mechanical alternans did not change in the patients who were not being treated with beta-blockers. The left ventricular ejection fraction increased in patients whose mechanical alternans could not be induced during the follow up, but decreased in the patients in whom mechanical alternans was repeatedly inducible. It is concluded that mechanical alternans is associated with the failing myocardium and may be potentially correctable.

Effect of beta-blocker therapy on severe ventricular arrhythmias in patients with idiopathic dilated cardiomyopathy

Beta-blocker therapy has been shown to improve cardiac function and prognosis in patients with idiopathic dilated cardiomyopathy (DCM). However, whether beta-blockers reduce severe ventricular arrhythmias and sudden cardiac death has not been clarified. The present study was designed to investigate the effects of beta-blockers on non-sustained ventricular tachycardia (VT) and sudden cardiac death in patients with DCM. Sixty-five patients with DCM treated with diuretics, digitalis and angiotensin-converting enzyme inhibitors were assigned to receive beta-blockers (n = 33) or not (n = 32). Mean follow-up was 53+/-30 months. The echocardiographic indices of cardiac function, the incidence of non-sustained VT on Holter monitoring electrocardiograms, and sudden cardiac death rate were compared between the 2 groups. Comparable improvement in cardiac function on echocardiograms was found in the 2 treatment groups. The patient group treated with beta-blockers showed a significant reduction in the prevalence of VT (from 43 to 15%, p<0.05) and the development of new episodes of VT (5 vs. 16%) compared to the group without beta-blockers. The sudden cardiac death rate did not differ between the 2 groups. The results of the present study suggest that beta-blockers are effective in reducing severe ventricular arrhythmias in patients with DCM.