Myocardial Fiber Diameter as a Good Indicator of Outcome in Batista's Operation

Early dystrophin loss is coincident with the transition of compensated cardiac hypertrophy to heart failure

Hypertension causes cardiac hypertrophy, one of the most important risk factors for heart failure (HF). Despite the importance of cardiac hypertrophy as a risk factor for the development of HF, not all hypertrophied hearts will ultimately fail. Alterations of cytoskeletal and sarcolemma-associated proteins are considered markers cardiac remodeling during HF. Dystrophin provides mechanical stability to the plasma membrane through its interactions with the actin cytoskeleton and, indirectly, to extracellular matrix proteins. This study was undertaken to evaluate dystrophin and calpain-1 in the transition from compensated cardiac hypertrophy to HF. Wistar rats were subjected to abdominal aorta constriction and killed at 30, 60 and 90 days post surgery (dps). Cardiac function and blood pressure were evaluated. The hearts were collected and Western blotting and immunofluorescence performed for dystrophin, calpain-1, alpha-fodrin and calpastatin. Statistical analyses were performed and considered significant when p<0.05. After 90 dps, 70% of the animals showed hypertrophic hearts (HH) and 30% hypertrophic+dilated hearts (HD). Systolic and diastolic functions were preserved at 30 and 60 dps, however, decreased in the HD group. Blood pressure, cardiomyocyte diameter and collagen content were increased at all time points. Dystrophin expression was lightly increased at 30 and 60 dps and HH group. HD group showed decreased expression of dystrophin and calpastatin and increased expression of calpain-1 and alpha-fodrin fragments. The first signals of dystrophin reduction were observed as early as 60 dps. In conclusion, some hearts present a distinct molecular pattern at an early stage of the disease; this pattern could provide an opportunity to identify these failure-prone hearts during the development of the cardiac disease. We showed that decreased expression of dystrophin and increased expression of calpains are coincident and could work as possible therapeutic targets to prevent heart failure as a consequence of cardiac hypertrophy.

Pyridostigmine restores cardiac autonomic balance after small myocardial infarction in mice

The effect of pyridostigmine (PYR) - an acetylcholinesterase inhibitor - on hemodynamics and cardiac autonomic control, was never studied in conscious myocardial infarcted mice. Telemetry transmitters were implanted into the carotid artery under isoflurane anesthesia. Seven to ten days after recovery from the surgery, basal arterial pressure and heart rate were recorded, while parasympathetic and sympathetic tone (ΔHR) was evaluated by means of methyl atropine and propranolol. After the basal hemodynamic recording the mice were subjected to left coronary artery ligation for producing myocardial infarction (MI), or sham operation, and implantation of minipumps filled with PYR or saline. Separate groups of anesthetized (isoflurane) mice previously (4 weeks) subjected to MI, or sham coronary artery ligation, were submitted to cardiac function examination. The mice exhibited an infarct length of approximately 12%, no change in arterial pressure and increased heart rate only in the 1st week after MI. Vagal tone decreased in the 1^st week, while the sympathetic tone was increased in the 1^st and 4^th week after MI. PYR prevented the increase in heart rate but did not affect the arterial pressure. Moreover, PYR prevented the increase in sympathetic tone throughout the 4 weeks. Concerning the parasympathetic tone, PYR not only impaired its attenuation in the 1^st week, but enhanced it in the 4^th week. MI decreased ejection fraction and increased diastolic and systolic volume. Therefore, the pharmacological increase of peripheral acetylcholine availability by means of PYR prevented tachycardia, increased parasympathetic and decreased sympathetic tone after MI in mice.

Noninvasive assessment of cardiac mechanics and clinical outcome after partial left ventriculectomy

BACKGROUND

Partial left ventriculectomy (PLV) was developed as a therapy for end-stage heart failure, but results were variable with few a priori predictors of outcome. Little is known about its effects on myocardial mechanics and their relation to clinical outcome.

METHODS

Twenty-four dilated cardiomyopathy patients underwent cardiac magnetic resonance imaging (MRI) before PLV, and 3 and 12 months after surgery. Left ventricular (LV) circumferential shortening and wall stress were computed at three short-axis levels. Exploratory outcome analysis grouped patients according to the timing of adverse cardiac events postsurgery.

RESULTS

LV mass and volume were decreased at each postsurgical time point (all p < 0.01). At 3 months, regional wall stress was reduced at all short-axis levels; but by 12 months stress was reduced from baseline only at the apex. Circumferential shortening was increased significantly at both postsurgical time points at each level. On average, septal shortening was negative (stretching) before surgery, but increased significantly, and was positive, postsurgery. Exploratory outcome analysis found that negative values of basal septum circumferential shortening before surgery increased the probability of event-free survival beyond 6 months.

CONCLUSIONS

Regional heterogeneity of LV myocardial function, associated with dilated cardiomyopathy, was diminished after PLV but was also related to patient outcome. MRI with tissue tagging is useful for assessing the efficacy of surgical therapies for congestive heart failure.

Persistent abnormal left ventricular systolic torsion in dilated cardiomyopathy after partial left ventriculectomy

OBJECTIVE

Rotation of the left ventricular apex relative to the base, or left ventricular torsion, is related to myocardial contractility and structure and is a sensitive indicator of cardiac dysfunction. We have quantified left ventricular systolic rotation and torsion in patients with dilated cardiomyopathy before and after partial left ventriculectomy in an attempt to characterize the effects of this surgical procedure on ventricular ejection mechanics.

METHODS

Magnetic resonance imaging with tissue tagging was performed before partial left ventriculectomy in 24 patients, 9 of whom underwent repeat imaging 3 months after surgery. Left ventricular rotation was quantified in each patient at three short-axis levels: apex, midventricle, and base. Torsion was defined as the difference between basal and apical rotation at any time. Results were subdivided for regional analysis at each level and related to cardiac function (ejection fraction, cardiac index, and velocity of circumferential fiber shortening).

RESULTS

Before surgery, left ventricular rotation was regionally heterogeneous and abnormal in magnitude and pattern, and increased end-systolic torsion was associated with better cardiac function. After surgery, clinical indices of cardiac function showed improvement; however, rotation magnitude was unchanged at the apex and reduced at the base and midventricle, particularly in the anterior wall and septum.

CONCLUSIONS

The pattern and magnitude of ventricular rotation were impaired by dilated cardiomyopathy. Left ventricular rotation and torsion were further diminished after partial left ventriculectomy, indicating that improvement in clinical indices of cardiac function was not reflective of an improvement in this measure of myocardial mechanics.

Left ventricular volume reduction surgery in the middle East

Heart transplantation is not yet socially acceptable in the Middle East, and left ventricular assist facilities are not generally available in this region. Therefore, left ventricular volume reduction surgery was attempted in 41 patients with end-stage heart failure (33 males; median age, 36.3 years) in 4 Middle Eastern tertiary referral centers between February 1996 and January 2001. Heart failure was due to idiopathic cardiomyopathy in 21 patients, ischemia in 11, rheumatic valvular disease in 8, and viral myocarditis in 1. Associated procedures were aortic valve replacement in 5 patients, mitral valve repair in 25, mitral valve replacement in 7, tricuspid valve repair in 6, and coronary bypass grafting in 8. Hospital mortality was 31.7%. Five patients were lost to follow-up. The survival rate of hospital survivors at 18 months was 65.2%. Three of the surviving patients did not benefit from the operation. Although our results were somewhat disappointing, this operation remains an option for surgeons working in developing areas of the world. It is hoped that better patient selection and new techniques of left ventricular volume reduction that avoid resection of viable muscle will further improve the outcome of this operation.

Relevance of apoptosis and cell proliferation for survival of patients with dilated cardiomyopathy undergoing partial left ventriculectomy

BACKGROUND

Cardiomyocyte apoptosis as well as proliferation have been described in congestive heart failure, but their clinical relevance remains unclear. In order to clarify whether apoptosis and cell proliferation occur in patients with idiopathic dilated cardiomyopathy and whether their degree in left ventricle fragments resected during partial left ventriculectomy has any influence on the outcome after this surgery, we compared their occurrence in four groups of patients: group A, short-term survivors (n = 18); group B, deaths within 6 months of the surgery (n = 13); group C, long-term survivors (n = 12); and Group D, deaths within 60 months (n = 19).

DESIGN

Apoptotic cardiomyocytes and interstitial cells were quantified in left ventricle fragments from 31 patients with idiopathic-dilated cardiomyopathy using the TUNEL assay. Cell proliferation was quantified in parallel sections by KI-67 immunohistochemistry.

RESULTS

Apoptotic cells were present in the majority of cases (n = 24) and proliferative cells in all cases. Whereas there was no significant difference regarding all parameters examined between Groups A and B, there was a highly significant difference between Groups C and D in the number of apoptotic cardiomyocytes (P = 0.012) and apoptotic interstitial cells (P = 0.006). There was no significant relationship between apoptotic cardiomyocytes and KI-67-positive cardiomyocytes, but a negative correlation between apoptotic interstitial cells and KI-67-positive interstitial cells (r = -0.383; P = 0.028).

CONCLUSION

Cardiomyocyte apoptosis and proliferation occur in the majority of patients with idiopathic-dilated cardiomyopathy. High numbers of apoptotic cardiomyocytes and apoptotic interstitial cells are significantly related to a bad late outcome after partial left ventriculectomy.