Cardiomyopathy
Isolated Left Ventricular Noncompaction Syndrome

https://doi.org/10.1016/j.amjcard.2009.05.062Get rights and content

Isolated left ventricular noncompaction (ILVNC) is a rare congenital cardiomyopathy characterized by prominent trabeculae, deep intertrabecular recesses, and thickened myocardium with 2 distinct layers (compacted and noncompacted). Clinical characteristics, outcomes, and appropriate therapies remain poorly defined. Data were collected on patients diagnosed with ILVNC by echocardiographic criteria at the Mayo Clinic from 2001 through 2006. These data were entered prospectively into a clinical database and retrospectively analyzed. All-cause mortality, stroke, and development of atrial fibrillation (AF) were compared to community and nonischemic dilated cardiomyopathic (DC) controls. Implantable cardioverter-defibrillator (ICD) therapies were examined. Thirty patients with confirmed ILVNC were included in analyses (mean age at diagnosis 39 ± 19.5 years, 60% men). Three patients with ILVNC died during follow-up (mean 2.5 ± 1.2 years) compared to 5 DC and 1 community controls. No mortality difference was observed among these groups (p = 0.42 and 0.054, respectively). No ILVNC deaths were observed in patients with normal LV ejection fraction. New-onset AF was diagnosed in 2 patients with ILVNC, and none was observed in DC controls. Stroke occurred in 2 DC controls and none was observed in patients with ILVNC. ICDs were implanted in 11 patients with ILVNC. No appropriate therapies were identified during follow-up, but 2 patients underwent inappropriate therapies related to AF. In conclusion, mortality in patients with ILVNC is similar to that in DC patients. Deaths were observed only in patients with decreased LV ejection fraction, suggesting that ICD therapy may be reserved for this subgroup. New-onset AF may lead to inappropriate ICD discharges.

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Methods

Patients were identified by searching the master diagnosis list and echocardiographic databases at the Mayo Clinic (Rochester, Minnesota) using the keywords “noncompaction” and “noncompaction” and the date range 2001 to 2006. Pediatric patients (age <16 years) and patients with other concomitant congenital heart disease were excluded. A comprehensive chart review was conducted to evaluate clinical data that were systematically entered into a database for analysis. Clinical data abstracted

Results

The initial database search identified 130 patients; 72 were excluded (46 had coexisting congenital disorders, 21 were <16 years old, 4 refused participation, and 1 had insufficient clinical information). Nineteen additional patients were excluded because index echocardiograms were unavailable for review. Echocardiographic data were reviewed in the remaining 39 patients. After study review of the images, 9 patients with echocardiographic reports listing ILVNC among the final diagnosis did not

Discussion

Awareness of ILVNC has increased substantially in recent years and it has been recognized as an “unclassified” cardiomyopathy by the World Health Organization.15 Interest has focused mainly on the concern that incompletely formed endocardium with channels and trabeculae may provide substrate for thromboembolic events, and that these patients might be at risk for the development of malignant ventricular tachyarrhythmias and LV systolic dysfunction. ILVNC has been the subject of several small,

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