Truncating titin mutations are associated with a mild and treatable form of dilated cardiomyopathy.

AIMS: Truncating titin mutations (tTTN) occur in 25% of dilated cardiomyopathy (DCM) cases, but the phenotype and severity of disease they cause have not yet been systematically studied. We studied whether tTTN variants are associated with a clinically distinguishable form of DCM. METHODS AND RESULTS: We compared clinical data on DCM probands and relatives with a tTTN mutation (n = 45, n = 73), LMNA mutation (n = 28, n = 29), and probands who tested negative for both genes [idiopathic DCM (iDCM); n = 60]. Median follow-up was at least 2.5 years in each group. TTN subjects presented with DCM at higher age than LMNA subjects (probands 47.9 vs. 40.4 years, P = 0.004; relatives 59.8 vs. 47.0 years, P = 0.01), less often developed LVEF <35% [probands hazard ratio (HR) 0.38, P = 0.002], had higher age of death (probands 70.4 vs. 59.4 years, P < 0.001; relatives 74.1 vs. 58.4 years, P = 0.008), and had better composite outcome (malignant ventricular arrhythmia, heart transplantation, or death; probands HR 0.09, P < 0.001; relatives HR 0.21, P = 0.02) than LMNA subjects and iDCM subjects (HR 0.36, P = 0.07). An LVEF increase of at least 10% occurred in 46.9% of TTN subjects after initiation of standard heart failure treatment, while this only occurred in 6.5% of LMNA subjects (P < 0.001) and 18.5% of iDCM subjects (P = 0.02). This was confirmed in families with co-segregation, in which the 10% point LVEF increase occurred in 55.6% of subjects (P = 0.003 vs. LMNA, P = 0.079 vs. iDCM). CONCLUSIONS: This study shows that tTTN-associated DCM is less severe at presentation and more amenable to standard therapy than LMNA mutation-induced DCM or iDCM.

Follow-up care by a genetic counsellor for relatives at risk for cardiomyopathies is cost-saving and well-appreciated: a randomised comparison.

Increasing numbers of patient relatives at risk of developing dilated or hypertrophic cardiomyopathy (DCM/HCM) are being identified and followed up by cardiologists according to the ACC/ESC guidelines. However, given limited healthcare resources, good-quality low-cost alternative approaches are needed. Therefore, we have compared conventional follow-up by a cardiologist with that provided at a cardiogenetic clinic (CGC) led by a genetic counsellor. Phenotype-negative first-degree relatives at risk for DCM/HCM were randomly assigned to see either a cardiologist or to attend a CGC. Uptake and resource use were recorded. For 189 participants, we evaluated quality of care experienced, patient satisfaction and perceived personal control (PPC) using validated questionnaires and estimated the average cost difference of these two modes of care. Maximum patient satisfaction scores were achieved more frequently at the CGC (86% vs 45%, P<0.01). In terms of follow-up care provided, the genetic counsellor did not perform worse than the cardiologist (95% vs 59%, P<0.01). The genetic counsellor more often enquired about the relative-at risk's health (100% vs 65%, P<0.01) and family health (97% vs 33%, P<0.01), measured blood pressure (98% vs 29%, P<0.01) and gave disease-specific information (77% vs 52%, P<0.01). Although PPC scores were equal in both groups, the average cost per patient of CGC follow-up was 25% lower. Follow-up of phenotype-negative relatives at risk for DCM/HCM at a CGC led to greater patient satisfaction and is well-appreciated at lower cost. CGC care is a good alternative to conventional cardiological follow-up for this growing group of patients.

The importance of the family history in caring for families with long QT syndrome and dilated cardiomyopathy.

In potentially inherited cardiac diseases, the family history is of great importance. We looked at the way cardiologists take a family history in patients with idiopathic dilated cardiomyopathy (DCM) or long QT syndrome (LQTS) and whether this led to screening of relatives or other follow-up. We performed retrospective cross-sectional analyses of adult index patients with DCM or LQTS in a general hospital (GH) or a University Medical Center (UMC). We identified 82 index patients with DCM (34 GH; 48 UMC) and 20 with LQTS (all UMC) between 1996 and 2005. Mean follow-up was 58 months. A family history was recorded in 90% of both LQTS and DCM patients most of the cases restricted to first-degree family members. The genetic aspects, counseling and screening of family members was discussed significantly more often with LQTS than DCM patients (all P < 0.05). Also follow-up (screening of family members, DNA analysis and referral) was performed significantly more often in LQTS than DCM patients. Cardiologists in the UMC referred DCM index patients for genetic counseling more often than those in the GH (25% vs. 6%; P < 0.05). Only a few index patients with DCM were referred to a clinical genetics department. One-third of DCM cases and nearly all LQTS cases are familial. Since early recognition and treatment may reduce morbidity and mortality we recommend cardiologists take a more thorough family history and always consider referring to a clinical genetics department in such index patients.