Longitudinal rotation: an unrecognised motion pattern in patients with dilated cardiomyopathy

BACKGROUND

Heart failure patients who are candidates for CRT frequently display longitudinal rotation (LR) - a swinging motion of the heart when imaged in a horizontal long-axis plane.

OBJECTIVES

To identify the magnitude and predictors of LR in patients with ischaemic (ICM) and idiopathic dilated (DCM) cardiomyopathy, and to assess predictive value of LR in patients undergoing cardiac resynchronisation therapy (CRT).

DESIGN AND SETTING

A retrospective study in a tertiary heart care setting.

METHODS

Echocardiography was performed in 45 ICM and 41 DCM patients who were CRT candidates and 16 control subjects. Global LR, segmental strains and segmental LR were assessed from echocardiograms using speckle tracking. Repeat echocardiography >40 days after the beginning of CRT was performed in 64 patients.

RESULTS

While DCM patients with QRS duration of both <130 ms and > or =130 ms displayed significant clockwise LR (p<0.001 for both vs 0), ICM patients and control subjects had LR that did not differ from 0. The most significant LR predictor was end-diastolic volume (p<0.001) followed by the absence of ischaemia (p<0.001) and QRS duration (p = 0.05). DCM patients with prominent clockwise LR had lower septal but higher lateral strains than DCM patients with minimal LR, or ICM patients with counterclockwise LR. LR correlated with decrease of end-systolic volume in DCM (r = 0.49, p = 0.004), while no relationship was observed in ICM.

CONCLUSION

Clockwise LR is linked to presence of DCM, with the small impact of QRS duration. LR is a moderately strong predictor of end-systolic volume decrease during CRT in DCM.

Myocardial fibrosis assessment by semiquantitative, point-counting and computer-based methods in patients with heart muscle disease: a comparative study

AIMS

No study has directly compared different histomorphometric methods of quantification of myocardial fibrosis. Therefore we compared the results of semiquantitative, point-counting and computer-based methods in the assessement of myocardial fibrosis in a consecutive series of endomyocardial biopsy samples from patients with heart muscle disease.

METHODS AND RESULTS

Histological samples (at least three per patient) were obtained by endomyocardial biopsy from 11 patients with focal myocarditis and from 24 ambulatory patients with idiopathic dilated cardiomyopathy, or during surgery in 10 patients who underwent partial left ventriculectomy. Samples were cut and stained with Masson-trichrome for better contrast. From each sample, a representative field was digitized, and the amount of fibrosis was assessed by semiquantitative scoring, by point-counting, and by computer-based software. Semiquantitative scoring correlated with both point-counting (Spearman's r = 0.69, P < 0.0001) and computer-based (Spearman's r = 0.83, P < 0.0001) methods. There was also a good correlation between point-counting and computer-based methods (r = 0.71, P < 0.0001). However, when compared with the point-counting method, the computer-based method overestimated percent fibrosis by 3.0 +/- 6.7% (P = 0.004). This overestimation correlated with the mean percent fibrosis (r = 0.38, P = 0.014).

CONCLUSIONS

Our data show good correlations between the three methods of myocardial fibrosis assessment. However, systematic differences between them emphasize that this should be taken into consideration when comparing results of the studies using different methods of fibrosis assessment.

Spontaneous ventricular arrhythmias following partial left ventriculectomy for nonischemic dilated cardiomyopathy: relation to hemodynamics and survival

The study assessed the value of ambulatory electrocardiogram (AECG) monitoring for identification of patients who are at increased risk for cardiac death or arrhythmic event following partial left ventriculectomy (PLV). Furthermore, the impact of PLV and its hemodynamics on the occurrence of spontaneous ventricular arrhythmias was assessed in long-term survivors. In 32 idiopathic dilated cardiomyopathy patients who underwent PLV, ambulatory ECG (AECG) was performed preoperatively, early postoperatively, and 6 months and 12 months after surgery. In 17 of 19 patients who survived > 12 months after the procedure, left ventricular (LV) angiography was performed at the same time points and was used to calculate LV ejection fraction, and end-diastolic and end-systolic wall stress. During a mean follow-up of 478 +/- 405 days, 11 cardiac events occurred. Cox univariate regression revealed frequency of premature ventricular contractions > 30/hour at baseline (p = 0.0213) and duration of heart failure symptoms (p = 0.0226) as predictors of cardiac death or arrhythmic event after PLV. In a multivariate analysis, only frequency of premature ventricular contractions > 30/hour was a significant predictor. There was no change in the frequency or severity of ventricular arrhythmias after PLV. However, frequency of premature ventricular contractions correlated with LV end-diastolic stress (r = 0.35, p = 0.013), and ejection fraction (r = -0.34, p = 0.016). Preoperative AECG monitoring may help stratification of PLV patients. Serial AECG did not show that PLV influence the incidence or the complexity of spontaneous ventricular arrhythmias. In contrast, it appears that a hemodynamically "successful" procedure may decrease the incidence of ventricular arrhythmias.

The "b" mutated gene in heterozygous Belgrade anemic rat

The Belgrade b/b rat has an autosomal recessive mutation which in homozygous state induces severe anemia. So far, this mutation has been considered a recessive one and the heterozygous animals (+/b) as phenotypically normal. In this study, we showed that at the hematologic level, the heterozygous animals acquire some of the anemic characteristics as well. Namely, the young +/b animal displays reticulocytosis of 3.1 +/- 1.0%, identical to b/b rat, compared with 0.8 +/- 0.4% in young normal animals. This conclusion was further supported by examination of beta-globin expression. The level of beta-globin mRNA in anemic and heterozygous reticulocytes is decreased, as estimated by dot blot hybridization, to 25% and 50% of normal level, respectively. Although inapparent phenotypically, b mutated allele disturbs early erythropoiesis and markedly decreases globin mRNA level in the heterozygous rat.