Relation of myocardial T2* to right ventricular function in thalassaemia major.

AIMS: Myocardial T2* cardiovascular magnetic resonance (CMR) provides a rapid and reproducible measure of cardiac iron loading and is being increasingly used worldwide for monitoring of transfusion-dependent thalassaemia patients. Although myocardial siderosis (T2* <20 ms) is associated with impaired left ventricular (LV) function, little is known of its relation with right ventricular (RV) function. The aim of this study was to investigate the relationship between cardiac T2* and RV function. METHODS AND RESULTS: A retrospective analysis of 319 patients with beta-thalassaemia major presenting for their first CMR scan was performed (45.1% male, mean age 25.6 years). In patients with normal myocardial T2* (>20 ms), the RV ejection fraction (EF) was within the normal range in 98% of patients. When myocardial T2* was <20 ms, there was a progressive and significant decline in RV EF. There was a linear relationship between RV and LV EF. CONCLUSION: Myocardial iron deposition is strongly associated with RV dysfunction, which mirrors the decrease in LV function seen with worsening cardiac iron loading. Right ventricular dysfunction may play a significant role in heart failure associated with myocardial siderosis.

Right ventricular volumes and function in thalassemia major patients in the absence of myocardial iron overload.

AIM: We aimed to define reference ranges for right ventricular (RV) volumes, ejection fraction (EF) in thalassemia major patients (TM) without myocardial iron overload. METHODS AND RESULTS: RV volumes, EF and mass were measured in 80 TM patients who had no myocardial iron overload (myocardial T2* > 20 ms by cardiovascular magnetic resonance). All patients were receiving deferoxamine chelation and none had evidence of pulmonary hypertension or other cardiovascular comorbidity. Forty age and sex matched healthy non-anemic volunteers acted as controls. The mean RV EF was higher in TM patients than controls (males 66.2 +/- 4.1% vs 61.6 +/- 6%, p = 0.0009; females 66.3 +/- 5.1% vs 62.6 +/- 6.4%, p = 0.017), which yielded a raised lower threshold of normality for RV EF in TM patients (males 58.0% vs 50.0% and females 56.4% vs 50.1%). RV end-diastolic volume index was higher in male TM patients (mean 98.1 +/- 17.3 mL vs 88.4 +/- 11.2 mL/m2, p = 0.027), with a higher upper limit (132 vs 110 mL/m2) but this difference was of borderline significance for females (mean 86.5 +/- 13.6 mL vs 80.3 +/- 12.8 mL/m2, p = 0.09, with upper limit of 113 vs 105 mL/m2). The cardiac index was raised in TM patients (males 4.8 +/- 1.0 L/min vs 3.4 +/- 0.7 L/min, p < 0.0001; females 4.5 +/- 0.8 L/min vs 3.2 +/- 0.8 L/min, p < 0.0001). No differences in RV mass index were identified. CONCLUSION: The normal ranges for functional RV parameters in TM patients with no evidence of myocardial iron overload differ from healthy non-anemic controls. The new reference RV ranges are important for determining the functional effects of myocardial iron overload in TM patients.

[Public access defibrillation]. / Ombres et lumières de l'accès public a la défibrillation.

Placement of automated external defibrillators (AED) in public facilities and training of the lay persons in basic life support-defibrillation (BLS-D) was recommended by the American Heart Association for the treatment of out-of-hospital cardiac arrest (OHCA). Immediate use of AED result in increase of survival to hospital discharge. Many observation and much less randomized trials describe clinical efficacy of this approach. However, "negative" trials have also been published and some recent data suggest that public access defibrillation (PAD) will have a minimal impact on population survival. In this article various PAD strategies were briefly reviewed. In our opinion installation of AED in public places should be based on the long-term study of local OHCA demography and preceded by widespread BLS training of lay population.

Prognostic role of CMR in patients presenting with ventricular arrhythmias.

OBJECTIVES: The goal of this study was to explore whether fibrosis detected by late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) is an independent predictor of hard cardiovascular events in patients presenting with ventricular arrhythmia. BACKGROUND: In patients at risk of sudden cardiac death, risk stratification for device therapy remains challenging. METHODS: A total of 373 consecutive patients with sustained ventricular tachycardia (VT) (n = 204) or nonsustained ventricular tachycardia (NSVT) (n = 169) underwent LGE-CMR. The group was prospectively followed up for a median of 2.6 years (range 11 months to 11 years). The predetermined endpoint was a composite of cardiac death/arrest, new episode of sustained VT, or appropriate implantable cardioverter-defibrillator discharge. RESULTS: Mean left ventricular (LV) ejection fraction (EF) was 60 ± 13%. The presence of fibrosis was a strong and independent predictor of the primary outcome for the whole group (hazard ratio [HR]: 3.3, 95% confidence interval [CI]: 1.8 to 5.8, p < 0.001). In the sustained VT subset, both LV fibrosis and severely impaired systolic function (LVEF <35%) were significant independent predictors in the multivariate model (HR: 3.0, 95% CI: 1.4 to 6.2, p = 0.001; and HR: 2.5, 95% CI: 1.1 to 6.2, p = 0.038, respectively). In the NSVT subset, the presence of fibrosis was the only independent predictor of the endpoint (HR: 4.2, 95% CI: 1.7 to 10.1, p = 0.006). CONCLUSIONS: LGE-CMR-detected fibrosis is an independent predictor of adverse outcomes in patients with ventricular arrhythmia and may have an important role in risk stratification. (The Prognostic Significance of Fibrosis Detection in Ischemic and Non-Ischemic Cardiomyopathy; NCT00930735).

Prognostic value of cardiovascular magnetic resonance in patients with suspected arrhythmogenic right ventricular cardiomyopathy.

BACKGROUND: Early recognition and accurate risk stratification are important in the management of arrhythmogenic right ventricular cardiomyopathy (ARVC). Identification of predictors of outcome by cardiovascular magnetic resonance (CMR) in patients undergoing evaluation for ARVC is limited. We investigated the predictive value of morphological abnormalities detected by CMR for major clinical events in patients with suspected ARVC. METHODS: We performed a longitudinal study on 369 consecutive patients with at least one criterion for ARVC. Abnormal CMR was defined by the presence of one of the following: increased right ventricular (RV) volumes, reduced RV ejection fraction, RV regional wall motion abnormalities, myocardial fatty infiltration, and myocardial fibrosis. The end-point was a composite of cardiac death, sustained ventricular tachycardia, ventricular fibrillation, and appropriate ICD discharge. RESULTS: Twenty patients met the composite end-point over a mean follow-up of 4.3±1.5 years. An abnormal CMR was an independent predictor of outcomes (p<0.001). The presence of multiple abnormalities heralded a particular high risk of events (HR 23.0, 95% CI 5.7-93.2, p<0.001 for 2 abnormalities; HR 35.8, 95% CI 9.7-132.6, p<0.001 for 3 or more abnormalities). The positive predictive value of an abnormal CMR study was 21.0% for an adverse event, whilst the negative predictive value of a normal CMR study was 98.8% over the follow-up period. CONCLUSIONS: CMR provides important prognostic information in patients under evaluation for ARVC. A normal study portends a good prognosis. Conversely, the presence of multiple abnormalities identifies a high risk group of patients who may benefit from ICD implantation.