Patients with mitral valve prolapse (MVP) have high risk of life-threatening ventricular arrhythmias (VAs). Data on the impact of exercise on arrhythmic risk in these patients are lacking. We explored whether lifetime exercise dose was associated with severe VA and with established risk factors in patients with MVP. Furthermore, we explored the circumstances at the VA event. In this retrospective cohort study, we included patients with MVP and assessed lifetime exercise dose as metabolic equivalents of task (MET) hours/week. Severe VA was defined as sustained ventricular tachycardia or fibrillation, aborted cardiac arrest, and appropriate shock by a primary preventive implantable cardioverter defibrillator. We included 136 MVP patients (48 years [interquartile range (IQR) 35–59], 61% female), and 17 (13%) had previous severe VA. The lifetime exercise dose did not differ in patients with and without severe VA (17 MET h/week [IQR 9–27] vs. 14 MET h/week [IQR 6–31], P = 0.34). Lifetime exercise dose > 9.6 MET h/week was a borderline significant marker for severe VA (OR 3.38, 95% CI 0.92–12.40, P = 0.07), while not when adjusted for age (OR 2.63, 95% CI 0.66–10.56, P = 0.17). Ventricular arrhythmia events occurred most frequently during wakeful rest (53%), followed by exercise (29%) and sleep (12%). We found no clear association between moderate lifetime exercise dose and severe VA in patients with MVP. We cannot exclude an upper threshold for safe levels of exercise. Further studies are needed to explore exercise and risk of severe VA.

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inheritable heart disease, whereas exercise-induced arrhythmogenic cardiomyopathy (EiAC) is a proposed acquired similar phenotype in athletes. The differences in disease progression between these entities are not well understood. This study aims to assess structural, functional, and arrhythmic disease progression in EiAC compared with ARVC. This longitudinal cohort study included EiAC patients who were competitive endurance athletes (>24 MET-hours/week for >6 consecutive years) referred due to ventricular arrhythmias (VA), without inherited or genetic factors or other evident causes, and genotype-positive ARVC patients with a definite diagnosis and their genotype-positive family members for comparison. Disease progression was assessed by repeated echocardiographic examinations and incident VA during long-term follow-up. The authors included 125 ARVC patients (61 women, aged 38 ± 17 years) and 41 EiAC patients (6 women, aged 45 ± 13 years) and followed them for 96 months (Q1-Q3: 73-132 months) and 82 months (Q1-Q3: 50-118 months), respectively. The authors analyzed 730 echocardiographic examinations (538 ARVC, 192 EiAC). Right ventricular (RV) structure and function remained stable in EiAC patients, whereas those in ARVC patients deteriorated during follow-up. The 5-year and 10-year cumulative incidences of VA were similar between EiAC and ARVC patients. RV structure and function deteriorated in ARVC patients but remained stable in EiAC patients during follow-up. The incidence of VA was high in both populations. These results indicate that EiAC patients should be followed closely over time regardless of structural and functional progression.

Background: A subset of patients with mitral valve prolapse (MVP) are at risk of life-threatening ventricular arrhythmias (VAs), and a high burden of premature ventricular contractions (PVCs) is associated with increased mortality in patients with MVP. Previous studies indicate that PVC burden could either increase with increasing heart rate (HR), decrease with increasing HR, or with no relationship to HR. The association between PVC burden and HR in MVP is not known, nor if there is an association with VAs. Purpose: We aimed to explore the relationship between PVC burden and HR in patients with MVP. Furthermore, we aimed to explore whether the different PVC profiles were associated with severe VA. Methods: In this cross-sectional ambispective outcome study, we included patients with MVP and available Holter monitorings with >100 PVCs per 24-hours seen at our tertiary centre. The Holter monitoring with the highest PVC burden was used in case of multiple recordings. We investigated the relationship between hourly PVC burden and hourly mean HR by univariable mixed linear regression. We defined PVC profiles as (1) fast-HR-dependent-PVC (F-HR-PVC) when there was a significant positive correlation, (2) slow-HR-dependent-PVC (S-HR-PVC) when there was a significant negative correlation, and (3) independent-HR-PVC (I-HR-PVC) when no correlation between PVC and HR was found. The significance was set to 0.05. Severe VA was defined as sustained ventricular tachycardia, non-sustained ventricular tachycardia with haemodynamic instability, ventricular fibrillation, aborted cardiac arrest, or appropriate shock by a primary preventive implantable cardioverterefibrillator. Severe VA was recorded from retrospective medical history, prospective ICD interrogation or monitoring with implantable loop recorder. Results: We included 75 patients with >100 PVCs at Holter monitoring (median age 48 years [IQR 35-58], 58% female). The median PVC burden was 1.9% per 24-hours (IQR 0.4-7.2). We found F-HR-PVC in 49 patients (65%), S-HR-PVC in 1 (1%), and I-HR-PVC in 25 (33%). Twelve (16%) patients had severe VA and these had higher PVC burden compared to those without severe VA (7.3% per 24-hours [IQR 4.2-10.4] vs 1.1% per 24-hours [IQR 0.3-5.3], p=0.004). The median PVC burden was 1.5% (IQR 0.3-8.0) for F-HR-PVC, 5.7% for S-HR-PVC and 1.5% (IQR 0.3-8.0) for I-HR-PVC. We found no association between different PVC profiles and the presence of severe VA (F-HR-PVC 65% vs 67%, S-HR-PVC 2% vs 0%, I-HR-PVC 33% vs 33%, p>0.05 for all groups). Conclusion: Fast-HR-dependent-PVC was most common in MVP patients, and slow-HR-dependent-PVC were rare. A higher PVC burden was associated with severe VA. However, different PVC profiles did not infer higher risk of severe VA in our study. Further studies are needed to explore whether distinct PVC profiles can predict severe VA in larger patient populations.

Peripartum cardiomyopathy (PPCM) occurs in 0.02% to 0.1% of live births in European countries. Truncating variants in the Titin gene (TTNtv) are the most common genetic findings in women with PPCM. However, data on pregnancy-associated cardiomyopathy (PAC) and pregnancy tolerance among TTNtv-positive women are limited. The objectives of the study were to report maternal cardiac outcomes during pregnancy and postpartum and fetal outcomes in women with TTNtv and to explore the effect of parity on long-term cardiac phenotype. We conducted an ambispective cohort study including consecutive TTNtv genotype-positive women, regardless of phenotype, with ≥1 cardiological evaluation. Data on pregnancies and maternal and fetal outcomes were collected from questionnaires and medical records. Arrhythmic burden and device implantation were recorded. Left ventricular dimensions and function were assessed by echocardiography. A total of 107 TTNtv-positive women were included (age 43 [IQR: 32-55] years, 17% probands). Among 78 women with prior pregnancies, 206 pregnancies resulted in 167 (81%) live births. PAC occurred in 3 of 167 live births and in 3 of 76 women, corresponding to a cumulative incidence of 1.8% and 3.9%. All affected women recovered completely with medical therapy. Remaining pregnancies were largely uncomplicated, without increased maternal or fetal adverse events. At median of 18 years (IQR: 9-31) after pregnancy, no differences were observed between parous and nulliparous women in arrhythmic burden, cardiac function, or ventricular dimensions. In this TTNtv-positive cohort, PAC incidence appeared higher than reported PPCM rates in the general European population. However, pregnancy was well tolerated and was not associated with adverse long-term cardiac remodeling.

Keratoconus is a progressive eye disease that results in thinning of the cornea, leading to visual impairment. Mitral valve prolapse (MVP) is a common disorder affecting around 2–4% of the general population. Previous studies have found an overrepresentation of MVP in individuals with keratoconus, with a prevalence of 38–65%, suggesting a shared underlying mechanism. In this case-control study, patients with keratoconus were enrolled from a quality and research registry. They were examined by a 2D echocardiography to identify if they had MVP, billowing or normal mitral leaflets. Controls were matched from the population-based Trøndelag Health Study. Patients and controls underwent a detailed echocardiographic examination to detect abnormal mitral valves. We included 101 patients (age 33 [IQR 29–40], 75% male) with keratoconus and 101 matched individuals. MVP was found in 2 (2%), while billowing was found in 5 (5%) of keratoconus patients. No significant association was found between keratoconus and the prevalence of MVP or billowing compared to the control group. Moreover, no associations were found between severity of keratoconus with presence of MVP nor with billowing of the mitral valves. We could not confirm the previously reported association between keratoconus and MVP, suggesting that routine screening for MVP in keratoconus patients may not be warranted. However, we cannot rule out the possibility of an association in other gender, age and ethnic groups different than ours.