Reliable detection of early myocardial dysfunction by tissue Doppler echocardiography in Becker muscular dystrophy

Risk Stratification of Genetic, Dilated Cardiomyopathies Associated With Neuromuscular Disorders: Role of Cardiac Imaging

The etiology of dilated cardiomyopathy (DCM) can be grouped as either genetic or nongenetic. More than 50 pathogenic genes have been described, with sarcomeric and lamin A/C mutations being the most common. Mutation carriers for genetic DCM are often asymptomatic until cardiac disease manifests with heart failure, arrhythmias, or sudden cardiac death. Preventive strategies are promising but can only be applied and tested adequately if genetic DCM can be diagnosed at an early stage. Early diagnosis of mutation carriers that may develop overt DCM requires advanced imaging techniques that can detect subtle structural and functional abnormalities. Advanced echocardiographic techniques such as tissue Doppler imaging and speckle tracking strain analysis permit early detection of functional abnormalities, whereas cardiovascular magnetic resonance techniques provide information on tissue characterization and myocardial energetics that may be altered at an early stage. Furthermore, nuclear imaging techniques provide information on cellular function (metabolism, perfusion). Once the diagnosis of overt DCM has been established, various imaging parameters such as echocardiography-based myocardial mechanics and cardiovascular magnetic resonance-based tissue characterization have shown incremental benefit to left ventricular ejection fraction in risk stratification. Further research is required to understand how imaging techniques may help to choose management strategies that could delay progression when instituted early in the course of the disease. The present article reviews the role of imaging in the risk stratification of genetic DCM in general, with specific emphasis on DCM associated with neuromuscular disorders.

Interventions for preventing and treating cardiac complications in Duchenne and Becker muscular dystrophy and X-linked dilated cardiomyopathy

BACKGROUND

The dystrophinopathies include Duchenne muscular dystrophy (DMD), Becker muscular dystrophy (BMD), and X-linked dilated cardiomyopathy (XLDCM). In recent years, co-ordinated multidisciplinary management for these diseases has improved the quality of care, with early corticosteroid use prolonging independent ambulation, and the routine use of non-invasive ventilation signficantly increasing survival. The next target to improve outcomes is optimising treatments to delay the onset or slow the progression of cardiac involvement and so prolong survival further.

OBJECTIVES

To assess the effects of interventions for preventing or treating cardiac involvement in DMD, BMD, and XLDCM, using measures of change in cardiac function over six months.

SEARCH METHODS

On 16 October 2017 we searched the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE and Embase, and on 12 December 2017, we searched two clinical trials registries. We also searched conference proceedings and bibliographies.

SELECTION CRITERIA

We considered only randomised controlled trials (RCTs), quasi-RCTs and randomised cross-over trials for inclusion. In the Discussion, we reviewed open studies, longitudinal observational studies and individual case reports but only discussed studies that adequately described the diagnosis, intervention, pretreatment, and post-treatment states and in which follow-up lasted for at least six months.

DATA COLLECTION AND ANALYSIS

Two authors independently reviewed the titles and abstracts identified from the search and performed data extraction. All three authors assessed risk of bias independently, compared results, and decided which trials met the inclusion criteria. They assessed the certainty of evidence using GRADE criteria.

MAIN RESULTS

We included five studies (N = 205) in the review; four studies included participants with DMD only, and one study included participants with DMD or BMD. All studied different interventions, and meta-analysis was not possible. We found no studies for XLDCM. None of the trials reported cardiac function as improved or stable cardiac versus deteriorated.The randomised first part of a two-part study of perindopril (N = 28) versus placebo (N = 27) in boys with DMD with normal heart function at baseline showed no difference in the number of participants with a left ventricular ejection fraction (LVEF%) of less than 45% after three years of therapy (n = 1 in each group; risk ratio (RR) 1.04, 95% confidence interval (CI) 0.07 to 15.77). This result is uncertain because of study limitations, indirectness and imprecision. In a non-randomised follow-up study, after 10 years, more participants who had received placebo from the beginning had reduced LVEF% (less than 45%). Adverse event rates were similar between the placebo and treatment groups (low-certainty evidence).A study comparing treatment with lisinopril versus losartan in 23 boys newly diagnosed with Duchenne cardiomyopathy showed that after 12 months, both were equally effective in preserving or improving LVEF% (lisinopril 54.6% (standard deviation (SD) 5.19), losartan 55.2% (SD 7.19); mean difference (MD) -0.60% CI -6.67 to 5.47: N = 16). The certainty of evidence was very low because of very serious imprecision and study limitations (risk of bias). Two participants in the losartan group were withdrawn due to adverse events: one participant developed an allergic reaction, and a second exceeded the safety standard with a fall in ejection fraction greater than 10%. Authors reported no other adverse events related to the medication (N = 22; very low-certainty evidence).A study comparing idebenone versus placebo in 21 boys with DMD showed little or no difference in mean change in cardiac function between the two groups from baseline to 12 months; for fractional shortening the mean change was 1.4% (SD 4.1) in the idebenone group and 1.6% (SD 2.6) in the placebo group (MD -0.20%, 95% CI -3.07 to 2.67, N = 21), and for ejection fraction the mean change was -1.9% (SD 9.8) in the idebenone group and 0.4% (SD 5.5) in the placebo group (MD -2.30%, 95% CI -9.18 to 4.58, N = 21). The certainty of evidence was very low because of study limitations and very serious imprecision. Reported adverse events were similar between the treatment and placebo groups (low-certainty evidence).A multicentre controlled study added eplerenone or placebo to 42 patients with DMD with early cardiomyopathy but preserved left ventricular function already established on ACEI or ARB therapy. Results showed that eplerenone slowed the rate of decline of magnetic resonance (MR)-assessed left ventricular circumferential strain at 12 months (eplerenone group median 1.0%, interquartile range (IQR) 0.3 to -2.2; placebo group median 2.2%, IQR 1.3 to -3.1%; P = 0.020). The median decline in LVEF over the same period was also less in the eplerenone group (-1.8%, IQR -2.9 to 6.0) than in the placebo group (-3.7%, IQR -10.8 to 1.0; P = 0.032). We downgraded the certainty of evidence to very low for study limitations and serious imprecision. Serious adverse events were reported in two patients given placebo but none in the treatment group (very low-certainty evidence).A randomised placebo-controlled study of subcutaneous growth hormone in 16 participants with DMD or BMD showed an increase in left ventricular mass after three months' treatment but no significant improvement in cardiac function. The evidence was of very low certainty due to imprecision, indirectness, and study limitations. There were no clinically significant adverse events (very low-certainty evidence).Some studies were at risk of bias, and all were small. Therefore, although there is some evidence from non-randomised data to support the prophylactic use of perindopril for cardioprotection ahead of detectable cardiomyopathy, and for lisinopril or losartan plus eplerenone once cardiomyopathy is detectable, this must be considered of very low certainty. Findings from non-randomised studies, some of which have been long term, have led to the use of these drugs in daily clinical practice.

AUTHORS' CONCLUSIONS

Based on the available evidence from RCTs, early treatment with ACE inhibitors or ARBs may be comparably beneficial for people with a dystrophinopathy; however, the certainty of evidence is very low. Very low-certainty evidence indicates that adding eplerenone might give additional benefit when early cardiomyopathy is detected. No clinically meaningful effect was seen for growth hormone or idebenone, although the certainty of the evidence is also very low.

Systemic sclerosis and the heart

Heart disease, either clinically apparent or silent, is a frequent complication of systemic sclerosis (SSc, scleroderma) and may affect both patients with diffuse cutaneous and limited cutaneous SSc. The availability of more sensitive modalities has led to an increased awareness of scleroderma heart disease, which often involves the pericardium, myocardium, and cardiac conduction system. This awareness of cardiac involvement requires attention and interventions led by internists, cardiologists, and rheumatologists. Although no specific therapy exists for scleroderma heart disease, early recognition of the presence and type of scleroderma heart disease may lead to more effective management of patients with scleroderma.

Blood glutathione decrease in subjects carrying lamin A/C gene mutations is an early marker of cardiac involvement

Dominant inherited Emery-Dreifuss muscular dystrophy and limb-girdle muscular dystrophy type 1B are due to mutations in the LMNA gene encoding lamin A/C and present similar life-threatening cardiac disease, the early diagnosis of which lacks reliable biomarkers. Glutathione depletion characterizes subjects with cardiac diseases of non-genetic aetiology. We examined blood glutathione in 22 LMNA-mutated subjects without altered left ventricular ejection fraction (LVEF>40%) measured by conventional echocardiography. Left and right ventricular (LV/RV) contractility was evaluated using echocardiography implemented with tissue-Doppler echography. Blood glutathione was positively correlated with LV and RV contractility (p<0.05), and was decreased by 23% in subjects with reduced LV/RV contractility compared to subjects with normal contractility. ROC analysis showed that blood glutathione reliably detected reduced LV/RV contractility (AUC-95% CI: 0.90 [0.76-1.04]; p=0.01). Blood glutathione decrease may allow the detection of reduced contractility in muscular dystrophic LMNA-mutated patients with still preserved LVEF.

Childhood onset of left ventricular dysfunction in a female manifesting carrier of muscular dystrophy

Duchenne muscular dystrophy and Becker muscular dystrophy are X-linked disorders that result from a mutation in the dystrophin gene that reduces the production or effectiveness of the protein dystrophin. These disorders are clinically characterized by progressive muscle degeneration. Manifesting female carriers are generally not identified as such until after puberty, when symptoms such as muscle weakness may arise. This clinical report describes a female manifesting carrier who started to show deterioration of left ventricular systolic function, but no marked skeletal muscle weakness, at the age of 10 years. The patient's cardiac function improved significantly after dual drug therapy with an ACE inhibitor (enalapril) and a beta-blocker (carvedilol). Our case adds to the existing evidence that left ventricular myocardial dysfunction may occur during childhood in female carriers of dystrophinopathies.

N-terminal Pro brain natriuretic peptide is a reliable biomarker of reduced myocardial contractility in patients with lamin A/C gene mutations

BACKGROUND

Recently, concerns have been raised about a possible lack of sensitivity of biomarkers to detect left ventricular (LV) dysfunction in patients with myopathies. We examined the ability of the N-terminal brain natriuretic peptide (NT-proBNP) to detect LV or right ventricular (RV) dysfunction in patients with lamin A/C (LMNA) gene mutations.

METHODS

We prospectively measured plasma NT-proBNP in consecutive patients with documented LMNA mutations and age-sex matched controls. All patients underwent standard echocardiography implemented by pulsed tissue-Doppler echocardiography (TDE).

RESULTS

Twenty-three patients were included (10 males, mean age 39.2 ± 18.9 years);10 had previous atrial arrhythmias, 8 had been implanted with cardioverter defibrillator for primary prevention of sudden death, 5 patients were of NYHA class II and 18 of NHYA class I. Sinus rhythm was recorded in all. NT-proBNP was increased in LMNA patients versus controls (123 ± 229 versus 26 ± 78 pg/ml, p=0.0004); 7 patients had depressed LV and/or RV contractility. Patients with reduced LV or RV contractility had increased mean NT-proBNP (341 ± 1032 pg/ml versus 80 ± 79 pg/ml in patients with normal myocardial contractility, p=0.004). Receiver-operating-characteristics analysis shows that NT-proBNP reliably detected depressed contractility (area under the curve 0.889 [0.697-1.000]). Sensitivity and specificity were 88% and 83% respectively, applying manufacturer's recommended cut-off concentration of 125 pg/ml.

CONCLUSION

NT-proBNP reliably detected the presence of reduced LV/RV contractility in LMNA patients.

Screening for cardiomyopathy in muscular dystrophy with tissue doppler imaging

OBJECTIVE

To study role of Tissue Doppler imaging (TDI) in identification of cardiomyopathy before development of ventricular dysfunction.

METHODS

Twenty-five patients with Duchenne's (DMD) and 10 with Becker's (BMD) muscular dystrophy along with 20 controls were evaluated using TDI.

RESULTS

Pulse Tissue Doppler signals of the lateral left ventricle wall (lateral mitral annulus) revealed reduced systolic velocities in the DMD patients (mean +/- SD: 7.8 +/- 1.1 cm/sec vs. 8.6 +/- 1.1 cm/sec in controls) in patients of DMD. 60% of the non ambulatory DMD (ejection fraction 45+/-9%) patients had mild LV dysfunction and reduced systolic velocities (6.96 +/- 1.7 cm/sec, p<0.05 vs controls). The ambulatory DMD patients also had reduced systolic velocities (7.8 +/- 1.1 cm/sec) though ejection fraction was normal. Reduced tissue Doppler systolic velocities in the ambulatory DMD patients with normal conventional echocardiography would suggest that perhaps some of these patients (20% had velocities less than Mean - 2 SD of controls) have early myocardial dysfunction (picked up only as abnormal myocardial velocities).

CONCLUSIONS

TDI picked up systolic dysfunction of the lateral wall in DMD even when overall LV function was normal conventional echocardiography. Tissue Doppler imaging is a useful technique to pick up early ventricular dysfunction and should be evaluated in larger studies and also with other techniques like magnetic resonance imaging.

Current understanding and management of dilated cardiomyopathy in Duchenne and Becker muscular dystrophy

PURPOSE

To review the current understanding of the pathophysiology of dilated cardiomyopathy (DCM) in patients with Duchenne and Becker muscular dystrophies, assessment of cardiac dysfunction for these patients, and the recommended pharmacological treatment options and ongoing research directions.

DATA SOURCES

Reviews and original research articles from scholarly journals and books.

CONCLUSIONS

Duchenne and Becker muscular dystrophies are debilitating neuromuscular disorders, both caused by mutations in the dystrophin gene. Most patients develop DCM as part of the disease course; in fact, DCM is the leading cause of death among these patients. Cardiac surveillance, including routine monitoring of electrocardiograms, echocardiograms, and appropriate blood biomarkers, may detect early DCM development. Although previous studies have shown that early administration of cardiac medications may delay the development of DCM, current standard of care does not emphasize cardiac surveillance and timely treatment. This, in turn, limits clinicians, including advanced practice nurses, to be optimally engaged in providing the most aggressive and proactive patient care.

IMPLICATIONS FOR PRACTICE

Implementing a routine cardiac assessment and timely pharmacological treatment in primary or specialty care settings is highlighted as an important step to optimize cardiac health among patients with Duchenne and Becker muscular dystrophies.

Cardiac involvement in Becker muscular dystrophy

The present review gives an overview of the clinical and subclinical manifestations of cardiac involvement (CI) in Becker muscular dystrophy (BMD), its pathophysiological background, diagnostic possibilities and therapeutic options for CI in BMD patients and carriers. CI may be subclinical or symptomatic. Up to 100% of patients develop subclinical CI. The onset of symptomatic CI is usually in the third decade of life, rarely in the first decade. One-third of patients develop dilative cardiomyopathy with concomitant heart failure. In BMD patients, CI manifests as electrocardiographic abnormalities, hypertrophic cardiomyopathy, dilation of the cardiac cavities with preserved systolic function, dilative cardiomyopathy or cardiac arrest. There is no correlation between CI and the severity of myopathy. CI is more prominent in patients than carriers. As soon as the diagnosis of BMD is established, a comprehensive cardiac examination should be performed. Because CI in BMD is progressive and adequate therapy is available, cardiac investigations need to be regularly repeated. If CI in BMD is recognized early, appropriate therapy may be applied early, resulting in a more favourable outcome.

Primary myocardial involvement in systemic sclerosis

Systemic sclerosis (SSc) is a connective tissue disease characterized by diffuse vascular lesions and fibrosis. Primary myocardial involvement is common in SSc and, when clinically evident, appears as a poor prognostic factor. An increasing body of evidence suggests that myocardial involvement is due, at least in part, to microcirculation impairment with abnormal vasoreactivity, with or without associated structural abnormalities of the small coronary arteries or arterioles. Using conventional methods, myocardial perfusion impairment, systolic and diastolic left ventricular dysfunction and right ventricular dysfunction have been reported in SSc. Recently, tissue Doppler echocardiography and magnetic resonance imaging have confirmed these results. Vasodilators, such as calcium channel blockers and angiotensin converting enzyme inhibitors, improve both myocardial perfusion and function abnormalities.

Detection of myocardial dysfunction in the presence of normal ejection fraction

Detection of subclinical myocardial involvement is of utmost importance in risk stratification and prognosis; the role of ejection fraction in the detection of subclinical disease may be unhelpful. Our aim was to evaluate the methodology and importance of early detection of myocardial involvement in the presence of normal ejection fraction. Most of the pertinent English and non-English articles published from 1980 to 2006 in Medline, Scopus, and EBSCO Host research databases have been reviewed. Serial assessment of systolic function with different techniques should be avoided, since imaging modalities and ejection fraction measurements are not interchangeable. Additional non-invasive tools still are needed for the identification of subclinical left ventricular dysfunction in certain diseases. The recognition of subclinical involvement will prompt initiation of specific therapy to prevent the development of overt left ventricular dysfunction. This also is needed for determining the best timing for intervention in asymptomatic patients with metabolic and valvular disorders.

Reduced myocardial contractility assessed by tissue Doppler echocardiography is associated with increased risk during adrenal surgery of patients with pheochromocytoma: report of a preliminary study

BACKGROUND

Depressed myocardial contractility, although rarely reported in pheochromocytoma, might be underestimated. It may be a determinant of perioperative risk during adrenal surgery.

METHODS

We prospectively studied consecutive patients with pheochromocytoma; myocardial function examined by standard and tissue Doppler echocardiography was compared with matched control subjects. The incidence of hemodynamic collapse during adrenal surgery was measured.

RESULTS

A total of 15 patients were included (8 men, 46 [17] years, hypertension in 10). All but one had a normal left ventricular ejection fraction. However, compared with control subjects, they had a depressed systolic strain rate (SR) (1.8 [2.1] vs 4.1 [2.2] s(-1), P = .007). Furthermore, 6 of 8 patients with systolic SR less than 2 s(-1) experienced intraoperative collapse, versus 1 of 7 with SR greater than 2 s(-1) (P = .041). No association was observed with other variables.

CONCLUSIONS

Patients with pheochromocytoma may have depressed myocardial contractility detected by tissue Doppler echocardiography despite a normal standard echocardiogram. A systolic SR less than 2 s(-1) was associated with an increased risk of perioperative collapse.

Effect of perindopril on the onset and progression of left ventricular dysfunction in Duchenne muscular dystrophy

OBJECTIVES

The aim of this research was to examine the effects of perindopril on cardiac function in patients with Duchenne muscular dystrophy (DMD).

BACKGROUND

Duchenne muscular dystrophy, an inherited X-linked disease, is characterized by progressive muscle weakness and myocardial involvement.

METHODS

In phase I, 57 children with DMD and a left ventricular ejection fraction (LVEF) >55% (mean 65.0 +/- 5.4%), 9.5 to 13 years of age (mean 10.7 +/- 1.2 years), were enrolled in a three-year multicenter, randomized, double-blind trial of perindopril, 2 to 4 mg/day (group 1), versus placebo (group 2). In phase II, all patients received open-label perindopril for 24 more months; LVEF was measured at 0, 36, and 60 months.

RESULTS

Phase I was completed by 56 (27 in group 1 and 29 in group 2) and phase II by 51 patients (24 in group 1 and 27 in group 2). There was no difference in baseline characteristics between the treatment groups. At the end of phase I, mean LVEF was 60.7 +/- 7.6% in group 1 versus 64.4 +/- 9.8% in group 2, and was <45% in a single patient in each group (p = NS). At 60 months, LVEF was 58.6 +/- 8.1% in group 1 versus 56.0 +/- 15.5% in group 2 (p = NS). A single patient had an LVEF <45% in group 1 versus eight patients in group 2 (p = 0.02).

CONCLUSIONS

Early treatment with perindopril delayed the onset and progression of prominent left ventricle dysfunction in children with DMD.

Evaluation of the effect of nifedipine upon myocardial perfusion and contractility using cardiac magnetic resonance imaging and tissue Doppler echocardiography in systemic sclerosis

BACKGROUND

Primary myocardial involvement due to microcirculation impairment is common in systemic sclerosis (SSc). Cardiovascular magnetic resonance imaging (MRI) and tissue Doppler echocardiography (TDE) were recently shown to be more sensitive than conventional methods for the respective assessment of myocardial perfusion and contractility. Previous studies have suggested that dihydropyridine-type calcium channel blockers mitigate both myocardial perfusion and function abnormalities.

OBJECTIVE

To investigate the effects of nifedipine on myocardial perfusion by MRI and on contractility by TDE, in patients with SSc.

PATIENTS AND METHODS

18 patients with SSc without clinical heart failure and with normal pulmonary arterial pressure (14 women, 4 men; mean (SD) age 59 (9) years; mean (SD) disease duration 7 (4) years, 10 with diffuse and 8 with limited cutaneous forms) were prospectively evaluated. The MRI perfusion index, determined from time-intensity curves, and systolic and diastolic strain rate determined by TDE were assessed at baseline, after a 72 hour vasodilator washout period, and after 14 days of oral treatment with nifedipine 60 mg/day.

RESULTS

Nifedipine treatment led to a significant increase in the MRI perfusion index (mean (SD) 0.26 (0.07) v 0.19 (0.05) at baseline, p = 0.0003) and in systolic and diastolic strain rate (2.3 (0.6) v 1.5 (0.4) s(-1) at baseline, p = 0.0002, and 4.2 (1.6) v 3.0 (1.2) at baseline, p = 0.0003, respectively).

CONCLUSION

Fourteen days of treatment with nifedipine simultaneously improves myocardial perfusion and function, as evaluated by highly sensitive and quantitative methods.