A relationship between mitral valve prolapse and subtypes of supraventricular tachycardia.

AIM: The aim of this study was to investigate the frequency of mitral valve prolapse (MVP) in patients with supraventricular tachycardia (SVT) who were diagnosed by intracardiac electrophysiological study (EPS). METHOD: The study was a retrospective cohort of 378 adult patients (128 males and 250 females, 17 to 63 years) admitted with EPS. We included 267 SVT patients (58.4 % (n = 156) atria-ventricular nodal reentrant tachycardia (AVNRT), 30 % (n = 80) atria-ventricular reentrant tachycardia (AVRT), 6.4 % (n = 17) atrial tachycardia (AT), and 5.2 % (n = 14) other). MVP prevalence was compared in individuals with SVT. RESULTS: MVP prevalence was found 27.7 % (n = 74) in patients with SVT. In subgroup analyses, there was a significant difference between AVRT and others about MVP prevalence (AVRT 52.7 % n = 39, AVNRT 33.8 % n = 25, AT 9.5 % n = 7, and others 4.1 % n = 3; p < 0.005). Also, there was a significant difference between females and males (75.7 % (n = 56); 24.3 % (n = 18); p < 0.05). There was a significant negative correlation between age and MVP just in female group (r = -0.116, p = 0.024). CONCLUSION: It was demonstrated in our study that AVRT and female sex may be related to MVP in SVT patients. It was dedicated from these results that the existence of arrhythmia should be focused on young female subjects with MVP more than the others.

[Electrolyte abnormalities and ventricular arrhythmias in children with mitral valve prolapse]. / Zaburzenia elektrolitowe i arytmia komorowa u dzieci z pierwotnym wypadaniem platków zastawki dwudzielnej.

The aim of this study was to determine plasma concentration of magnesium, potassium, calcium and sodium in children with mitral valve prolapse (MVP) and to establish the relation between electrolyte abnormalities and ventricular arrhythmias (VA). The study group consists of the 113 children with MVP (age +/- SD: 10.7 +/- 4.3 years). The 101 healthy children (age +/- SD: 13.0 +/- 3.2 years) were enrolled into the control group. All patients underwent clinical examination, standard ECG, 24 hr ECG Holter monitoring and echocardiography. Blood samples were taken 3 times in fasting state in separate days. All patients were in sinus rhythm. Cardiac arrhythmias were observed more frequently in children with MVP (53%) than in control group (31%, p < 0.0008). VA were recorded in 39% MVP patients, compared with 13% of the healthy children (p < 0.0001). There were no differences in K, Na and Ca concentrations in children with MVP comparing to control group. Serum Mg concentration was significantly lower in MVP group (0.88 +/- 0.08 mmol/l) comparing to healthy children (0.91 +/- 0.07 mmol/l, p < 0.002). A marked decrease in Mg concentration was recorded in patients with MVP and ventricular arrhythmias compared with those without ventricular arrhythmias (0.83 +/- 0.07 vs 0.90 +/- 0.06 mmol/l, p < 0.0001). This study demonstrates that potentially serious dysrhythmias are common in pediatric patients with MVP. It would appear that ambulatory ECG monitoring should be part of the complete evaluation of children with MVP. Since decreased plasma concentration, magnesium supplementation seems to be a prudent approach in children MVP with frequent ventricular premature beats and in children with ventricular tachycardia.

Hypomagnesemia and mitral valve prolapse in Cavalier King Charles spaniels.

There is a high incidence of mitral valve prolapse (MVP), an abnormal displacement of one or both mitral valve leaflets during systole, in Cavalier King Charles Spaniels (CKCS). In humans, MVP is known to be associated with a low magnesium status. In this study, the plasma magnesium concentration was measured in 30 CKCS without heart failure. It was also investigated whether MVP-severity and degree of regurgitation correlated with plasma magnesium and a number of parameters of the renin-angiotensin system, and whether 4 weeks magnesium supplementation affected plasma magnesium or the high renin/low aldosterone profile associated with MVP. A high prevalence of hypomagnesemia was observed: plasma concentrations < 0.70 mmol/l were found in 15 dogs (50%) before and in 12 dogs (40%) after 4 weeks magnesium supplementation. The mean plasma level was 0.69 +/- 0.07 mmol/l before and 0.71 +/- 0.07 mmol/l after magnesium (P = 0.22). Plasma magnesium concentrations did not correlate with MVP-severity and degree of regurgitation. Plasma aldosterone levels correlated negatively with MVP-severity and positively with the degree of regurgitation, and serum angiotensin-converting enzyme activities correlated negatively with the degree of regurgitation. Magnesium supplementation had no effects on renin and aldosterone nor on the ratio between the two. In conclusion, many CKCS without heart failure have hypomagnesemia whether they are fed supplementary magnesium or not--a finding which may be associated with the high prevalence of MVP in this breed. Further studies, however, are needed to clarify the role of a low magnesium status in canine MVP.

[Clinical survey of 126 cases with mitral valve prolapse detected at the annual health check-up].

Clinical and echocardiographic survey of mitral valve prolapse (MVP) was performed in 616 cases, which were selected from about 6,000 health check-up. An echocardiographic study revealed MVP in 126 cases. The prevalence of MVP was about 2% (health check-up survey) and 20.5% (echo study). The male and female ratio was 102/24. Frequent premature contractions, isolated atrial fibrillation and an apical systolic murmur were more frequently associated with MVP. Among 13 cases of isolated atrial fibrillation, seven with MVP were permanent, while other six without MVP were transient. Most cases (77%) were asymptomatic. Mild mitral regurgitation proved by auscultation and phonocardiography was observed in only two cases (1.6%), and most of the cases (81%) had no mitral regurgitant signals by a Doppler study.