RESUMO
Background: Mitral regurgitation (MR) is common in patients with ischemic or idiopathic cardiomyopathies and may be associated with a poor prognosis; however, the impact of different degrees of MR on cardiovascular magnetic resonance images, left ventricular features, and clinical outcomes of left ventricular noncompaction are unknown. We aimed to investigate and compare cardiovascular magnetic resonance characteristics and clinical consequences in patients with left ventricular non-compaction (LVNC) with and without MR. Methods: A cohort of 75 patients with left ventricular noncompaction were retrospectively studied from three institutions; all had undergone cardiovascular magnetic resonance examination with subsequent clinical follow-up. MR was evaluated by echocardiography. Left ventricular myocardial strains including global radial, circumferential, and longitudinal peak strains and left ventricular geometric and functional parameters, including left ventricular ejection fraction, end-diastolic volume, end-systolic volume, left ventricular mass, left ventricular sphericity index, longitudinal shorten, and late gadolinium enhancement (LGE) were measured and compared among groups. The primary endpoint was a composite of heart transplantation, implantable cardioverter-defibrillator insertion, and cardiac death. Results: Compared with the no MR group, the MR groups showed significant deterioration in left ventricular myocardial strains (all P<0.05), and impaired left ventricular geometry and function, including lower left ventricular ejection fraction and greater left ventricular end-systolic volume and left ventricular mass (P<0.05). In the subgroup of moderate-severe MR, patients showed more impaired cardiovascular magnetic resonance features, including left ventricular sphericity index, left ventricular end-diastolic volume, and longitudinal shorten (P<0.05). In this subgroup, Kaplan-Meier analysis showed a significant difference in clinical outcomes (log-rank χ2=4.516, P=0.034; log-rank χ2=4.419, P=0.036, respectively). Additionally, multivariate analyses showed a 6.5-fold higher [hazard ratio, 6.5 (95% CI, 1.015-41.881)] risk of cardiac death with LGE in the moderate-severe MR cohort. Conclusions: In patients with left ventricular noncompaction, MR induced more maladaptive left ventricular remodeling. The incidence of adverse outcomes may be related to the degree of MR. In moderate-severe MR patients, coexisting of LGE may have an additive deleterious effect on clinical outcomes.
RESUMO
BACKGROUND: Left ventricular noncompaction (LVNC) is a rare type of cardiomyopathy, and one of its clinical manifestations is arrhythmia. Cardiovascular magnetic resonance (CMR) is valuable for the diagnosis and prognosis of LVNC. However, studies are lacking on the use of CMR for LVNC patients with arrhythmia. This study aimed to characterize and compare CMR features and prognosis in LVNC patients with and without arrhythmia. METHODS: Eighty-four LVNC patients diagnosed by CMR were enrolled retrospectively in this study. Clinical data, arrhythmia characteristics, and CMR parameters were collected. Patients were divided into different groups according to the arrhythmia characteristics and CMR manifestations for statistical analysis and comparison. Ventricular tachycardia (VT), ventricular fibrillation (Vf), ventricular flutter (VFL), III° atrioventricular block (III° AVB), Wolff-Parkinson-White syndrome (WPW) and ventricular escape (VE) were defined as malignant arrhythmias and benign arrhythmias included premature ventricular contraction, atrial premature beats, atrial fibrillation, supraventricular tachycardia, supraventricular premature beat, bundle branch block, atrial flutter and sinus tachycardia. The outcome events were defined as a composition event of cardiac death, rehospitalization for heart failure, heart transplantation, and implantation of an implantable cardioverter defibrillator (ICD). RESULTS: Sixty-seven LVNC patients (79.76%) mainly presented with arrhythmia, including premature ventricular beat (33 patients [27.73%]), bundle branch block (14 patients [11.77%]), electrocardiogram waveform changes (18 patients [15.13%]), and ventricular tachycardia (11 patients [9.24%]). The cardiac function and structure parameters had no significant difference among the nonarrhythmia group, benign arrhythmia group, and malignant arrhythmia group. However, the presence of late gadolinium enhancement (LGE) was higher in the malignant arrhythmia group than in the other two groups (p = 0.023). At a mean follow-up of 46 months, cardiac events occurred in twenty-three patients (46.94%). Kaplan-Meier analysis showed that there was no statistically significant difference in prognosis among the nonarrhythmia, benign, and malignant arrhythmia groups, but the patients with arrhythmia and association with LGE + or left ventricular ejection fraction (LVEF) < 30% had a higher risk than patients with LGE- or LVEF > 30% (LGE +, HR = 4.035, 95% CI 1.475-11.035; LVEF < 30%, HR = 8.131, 95% CI 1.805-36.636; P < 0.05). CONCLUSIONS: In LVNC patients, the types of arrhythmias are numerous and unrepresentative, and arrhythmia is not the prognostic factor. Arrhythmia combined with presence of LGE or LVEF < 30% is associated with poor prognosis in LVNC patients.
