Isolated Left Ventricular Noncompaction in a 90-Year-Old Man

Abstract

Isolated ventricular myocardial noncompaction is a cardiomyopathy that is being diagnosed more frequently in patients of all ages because of increased awareness and improvements in imaging methods. It is an extremely rare cause of heart failure in nonagenarians. We describe the case of a man who presented with heart failure for the first time at 90 years of age. The diagnosis was isolated left ventricular noncompaction. Transthoracic echocardiography showed a trabeculated, sponge-like appearance of the left ventricular apical and inferolateral segments. After medical management, the patient was asymptomatic at the 3-month follow-up examination.

Knowledge of ventricular noncompaction is increasing within the cardiology community. Patients who have isolated noncompaction with a limited number of involved ventricular segments can live beyond normal life expectancy without developing heart failure. In addition to discussing our patient's case, we briefly review the relevant medical literature.

Myocardial noncompaction, often called isolated ventricular noncompaction or left ventricular noncompaction (LVNC), is an increasingly recognized cardiomyopathy characterized by prominent trabeculae, deep endocardial recesses, and a sponge-like morphologic appearance of the myocardium. In earlier studies,¹ noncompaction was detected in approximately 0.05% of patients who underwent echocardiographic examination; however, the true overall prevalence of the condition is not known.² Since the introduction of the term describing the isolated noncompaction of left ventricular (LV) myocardium,³ LVNC has become widely recognized and has gained interest as a form of cardiomyopathy.⁴

Myocardial noncompaction can occur in isolation or in association with cardiac syndromes or disease.³ Although the LV is usually affected, biventricular involvement^5,6 and predominant right ventricular noncompaction⁷ have been reported. Myocardial noncompaction can occur at any age; the clinical presentation is nonspecific and varies from no symptoms to conduction defects, thromboembolism, ventricular arrhythmias, severe heart failure, or sudden cardiac death.^8,9 We describe the case of a patient who first presented with symptoms of heart failure at age 90 years. We discuss the diagnosis of LVNC and review the relevant medical literature.

Case Report

In September 2010, a 90-year-old man presented at our institution's emergency department with progressive shortness of breath and generalized weakness that had started during the previous month. He had no chest pain, palpitations, or syncope. His medical history included osteoarthritis and pacemaker placement for the treatment of sick sinus syndrome. At presentation, his vital signs were normal. He was admitted for additional testing. Physical examination revealed bilateral crackles in the lower-lung fields. Neurologic findings were unremarkable. An electrocardiogram showed a ventricular paced rhythm. A chest radiograph revealed mild cardiomegaly and pulmonary vascular congestion. The results of routine biochemical tests were within normal limits, except for an elevated pro-brain natriuretic peptide level (1,540 pg/mL). Transthoracic echocardiography revealed a trabeculated, sponge-like appearance of the apical and inferolateral segments of the LV (Fig. 1). The patient also had mild systolic dysfunction and an ejection fraction of 0.40. Moderate mitral and tricuspid regurgitation and pulmonary hypertension were noted (peak systolic pulmonary artery pressure, 45 mmHg). In the apical LV segments, the end-systolic ratio of noncompacted-to-compacted myocardium was >3:1. Color-flow Doppler echocardiography showed blood flow in deep intertrabecular recesses. Mitral inflow velocities and tissue-Doppler examination revealed a restrictive pattern of diastolic dysfunction. Morphologically, the heart valves were normal, and no coexisting congenital anomaly was found. Contrast enhancement improved the quality of the echocardiographic images by demarcating the endocardial borders (Fig. 2). Additional biochemical and enzymatic studies ruled out a metabolic defect or storage disease. These findings led to the diagnosis of LVNC. Cardiovascular magnetic resonance imaging (CMR), endomyocardial biopsy, and genetic studies were not performed. The patient had no family history of LVNC.

Fig. 1 Transthoracic echocardiogram (apical 4-chamber view) shows the hypertrabeculated, sponge-like appearance (arrow) of the apical and inferolateral left ventricular segments.

Fig. 2 Contrast-enhanced echocardiogram shows demarcated endocardial borders. The arrow points to the trabeculations.

The patient had no significant arrhythmias during his hospital stay. After medical management with β-blockers, angiotensin-converting enzyme inhibitors, and a loop diuretic, he was asymptomatic at the 3-month follow-up examination.

Discussion

We have described the diagnosis of LVNC in a 90-year-old man. The patient had been asymptomatic until mild symptoms of congestive heart failure developed during the month before initial presentation. He responded well to medical management of this very rare cause of heart failure in an individual of his age.

Myocardial noncompaction is thought to result from the interruption of myocardial morphogenesis during embryonic development,^3,5 although there is some controversy as to whether the condition can also be acquired.^1,4 After the 4th week of embryogenesis, the myocardium is composed of a loose, myofibrillary network separated by deep recesses. This spongiform, sinusoidal tissue becomes more compact from the endocardium to the epicardium and from the base to the apex. Arrest of this normal compaction results in noncompaction.¹⁰

When symptoms are present at all, the major clinical features of LVNC are heart failure, arrhythmias, and thromboembolic events.^3,11 In 2 of the largest populations analyzed to date,^8,9 the mortality rate from sudden cardiac death in patients with LVNC was 8% to 9%. Heart-failure symptoms, which were present in 56% of patients in a systematic overview of 5 eligible studies,⁹ can range from very mild to severe. Both systolic and diastolic dysfunction can develop. Systolic dysfunction and arrhythmias might be secondary to microcirculatory dysfunction and subepicardial hypoperfusion.¹¹ More adults than children present with thromboembolic events or arrhythmias.^2,5,11 Thromboembolic events have involved the brain, lungs, and mesenteric organs.^3,11 Embolic events are presumed to result from de novo thrombus formation in the LV trabeculae secondary to LV systolic dysfunction or from intra-atrial clot formation, especially in patients with atrial fibrillation.⁵

In a recent analysis,⁹ it was determined that 18% to 42% of LVNC cases were familial. However, the phenotype of patients with noncompaction can vary even within familial cases and range from clinically benign to fatal. Genetic and imaging studies are justified in first-degree relatives of affected individuals, to identify potential risks and possibly the causative genes.^4,9

Echocardiographically calculating the total number of involved segments in each patient could provide important prognostic information and help guide clinical decisions. In a retrospective analysis of 17,229 examinations performed in pediatric patients at Stanford University, 44 patients (0.3%) met the echocardiographic criteria for LV myocardial noncompaction.¹² This study, which investigated the determinants of outcomes in these patients, found that a larger number of affected segments (6 vs 4 segments) was statistically associated with poor outcome, including low ejection fraction, heart transplantation, and death. After adjustment for associated congenital heart disease, the increased risk with the involvement of more than 5 segments was unchanged. Of note, the mean follow-up for patients who showed a better prognosis was only 18 months.¹² Our case supports their findings: our patient remained asymptomatic for 90 years. He appeared to have only apical and inferolateral involvement, with sparing of the midpapillary and basal myocardial regions.

Echocardiography is crucial for the diagnosis of LVNC. Widely accepted diagnostic criteria¹³ include the following:

1. An excessively thick myocardial wall structure in 2 differing layers—a thin, compacted epicardial layer and a thicker, noncompacted endocardial layer

2. A characteristic end-systolic ratio of >2:1 for noncompacted-to-compacted wall thickness

3. Prominent multiple, chiefly intracavitary trabeculae, with color-Doppler echocardiographic evidence of communication between the deep intertrabecular recesses and the ventricular cavity

4. No cardiac abnormalities beyond the above, in isolated noncompaction cases.

Lowery and colleagues¹⁴ reported the first use of contrast-enhanced echocardiography for the diagnosis of LVNC. In our patient, this method facilitated diagnosis by demarcating the endocardial borders, thus improving the quality of the images. Alternative tools for the diagnosis of LVNC are contrast ventriculography, computed tomography, and CMR. Petersen and colleagues¹⁵ reported that CMR shows the extent of involvement and the exact location of noncompacted segments. After intravenous gadolinium injection, the 2 different myocardial layers can be seen on T₂-weighted images. Endomyocardial biopsy yields no specific findings but can be used to rule out certain inherited storage disorders, such as Fabry disease. Usually, biopsy specimens display fibrosis with necrotic myocytes in the interstitial fibrotic areas.¹¹

In patients with LVNC, treatment options vary on an individual basis, ranging from medical management in mild cases to heart transplantation in patients with refractory symptoms. Monitoring asymptomatic patients is encouraged, whether diagnosis is incidental or the consequence of familial screening, because of possible future complications in those individuals.^8,9 Our patient's mild symptoms responded well to medical therapy, and his short-term prognosis was excellent.

Although LVNC is an extremely rare cause of heart failure in nonagenarians, it should be included in the differential diagnosis in patients of that age who present with first-time symptoms. Knowledge and awareness of LVNC are increasing within the echocardiographic and cardiology communities, and these are requisite to the recognition of LVNC. Our case shows that patients with a limited number of involved LV segments can live beyond normal life expectancy without developing heart failure.

Acknowledgment

We thank Nicole Stancel, PhD, of the Texas Heart Institute at St. Luke's Episcopal Hospital, for editorial assistance with this manuscript.