Systemic primary carnitine deficiency induces severe arrhythmia due to shortening of QT interval.

BACKGROUND: Systemic primary carnitine deficiency (PCD) is characterized by cardiomyopathy and arrhythmia. Without carnitine supplementation, progression is usually towards fatal cardiac decompensation. While the cardiomyopathy is most likely secondary to energy deficiency, the mechanism of arrhythmia is unclear, and may be related to a short QT interval. OBJECTIVE: We aim to describe rhythmic manifestations at diagnosis and with carnitine supplementation. METHODS: French patients diagnosed for PCD were retrospectively included. Clinical and para clinical data at diagnosis and during follow-up were collected. Electrocardiograms with QT interval measurements were blinded reviewed by two paediatric cardiologists. RESULTS: Nineteen patients (median age at diagnosis 2.3 years (extremes 0.3-28.9)) followed in 8 French centres were included. At diagnosis, 21% of patients (4/19) had arrhythmia (2 ventricular fibrillations, 1 ventricular tachycardia and 1 sudden death), and 84% (16/19) had cardiomyopathy. Six electrocardiograms before treatment out of 11 available displayed a short QT (QTc < 340 ms). Median corrected QTc after carnitine supplementation was 404 ms (extremes 341-447) versus 350 ms (extremes 282-421) before treatment (p < 0.001). The whole QTc was prolonged, and no patient reached the criterion of short QT syndrome with carnitine supplementation. Three patients died, probably from rhythmic cause without carnitine supplementation (two extra-hospital sudden deaths and one non-recoverable rhythmic storm before carnitine supplementation), whereas no rhythmic complication occurred in patients with carnitine supplementation. CONCLUSION: PCD is associated with shortening of the QT interval inducing severe arrhythmia. A potential explanation would be a toxic effect of accumulated fatty acid and metabolites on ionic channels embedded in the cell membrane. Carnitine supplementation normalizes the QTc and prevents arrhythmia. Newborn screening of primary carnitine deficiency would prevent avoidable deaths.

Comparison of Serum Selenium Levels Between Patients with Newly Diagnosed Atrial Fibrillation and Normal Controls.

Atrial fibrillation (AF) is the most common sustained dysrhythmia in the elderly population. It is estimated to affect more than 30 million people worldwide. AF occurs when abnormal electrical impulses start to activate in the atria and override the heart's natural pacemaker, which can no longer control the heart's rhythm. Since atrial contractility is impaired in AF, blood flow in the atria becomes stasis over time and causes thrombus formation. This thrombus causes the risk of embolism and causes complications such as stroke. Therefore, it is a fundamental cause of cardiovascular mortality and morbidity. The diagnosis of AF is usually made with the help of electrocardiography (ECG). The absence of P waves in ECG and irregular R-R interval is sufficient for diagnosis. AF is most commonly associated with advanced age, hypertension, diabetes mellitus, thyroid dysfunction, obesity, alcohol use, physical inactivity, and underlying ischemic heart diseases. As well as to all these usual risk factors, electrolyte disorders and mineral deficiencies also play an essential role in the etiology of AF. Previous studies have clearly demonstrated that serum electrolyte changes have a role in the etiology of AF. These include electrolytes such as serum magnesium, calcium, potassium, and chloride. However, there is not enough information in the literature about the effects of trace elements on AF. Selenium is a trace element that plays an important role in many systems in the human body. It has a vital role in inflammation, regulation of antioxidant reactions, and fibrosis of tissues in both animals and humans. It is known that selenium deficiency causes many cardiovascular diseases such as heart failure, coronary artery disease, and arrhythmia. Our study aimed to compare serum selenium levels in newly diagnosed AF patients with the healthy control group.

Accelerated Idioventricular Rhythm Following Intraoral Local Anesthetic Injection During General Anesthesia.

Some anesthetic agents or adjunct medications administered during general anesthesia can cause an accelerated idioventricular rhythm (AIVR), which is associated with higher vagal tone and lower sympathetic activity. We encountered AIVR induced by vagal response to injection-related pain following local anesthetic infiltration into the oral mucosa during general anesthesia. A 48-year-old woman underwent extraction of a residual tooth root from the left maxillary sinus under general anesthesia. Routine preoperative electrocardiogram (ECG) was otherwise normal. Eight milliliters of 1% lidocaine (80 mg) with 1:100,000 epinephrine (80 µg) was infiltrated around the left maxillary molars over 20 seconds using a 23-gauge needle and firm pressure. Widened QRS complexes consistent with AIVR were observed for ∼60 seconds, followed by an atrioventricular junctional rhythm and the return of normal sinus rhythm. A cardiology consultation and 12-lead ECG in the operating room produced no additional concerns, so the operation continued with no complications. AIVR was presumably caused by activation of the trigeminocardiac reflex triggered by intense pain following rapid local anesthetic infiltration with a large gauge needle and firm pressure. Administration of local anesthetic should be performed cautiously when using a large gauge needle and avoid excessive pressure.

Results of carotid sinus massage in a tertiary referral unit--is carotid sinus syndrome still relevant?

BACKGROUND: carotid sinus hypersensitivity (CSH) is associated with syncope, drop attacks and unexplained falls in older people. However, a recent study has also reported a prevalence of 35% in asymptomatic community-dwelling older people. OBJECTIVE: we conducted a retrospective observational study to investigate the haemodynamic and symptom responses of a large cohort of patients undergoing carotid sinus massage (CSM). METHODS: the electronically stored haemodynamic data of 302 consecutive patients, aged 71 +/- 11 years, investigated with CSM for unexplained falls and syncope was analysed. Bilateral sequential CSM was performed in the supine and upright positions with continuous electrocardiogram (ECG) and non-invasive beat-to-beat blood pressure monitoring (Taskforce, CN Systems, Austria). CSH (CSH) was defined by maximal R-R interval > or =3 s (cardioinhibitory) and/or a systolic blood pressure drop of > or =50 mmHg (vasodepressor). RESULTS: a total of 74/302 (25%) subjects had CSH, 37 (50%) of which were cardioinhibitory (CI) and 37 (50%) were vasodepressor (VD) subtypes. Subjects with positive CSM were significantly older (75.2 vs 70.2 years, P < 0.001), and more likely to be male (32% vs 19%, P < 0.01). CSH was diagnosed with right-sided CSM alone in 45 (61%) subjects and erect CSM only in 36 (49%) subjects. Symptom reproduction was more likely with the CI than the VD subtypes (82% vs 28%; P < 0.001). CONCLUSION: CSH was diagnosed in 25% of patients investigated with CSM at our specialist unit, lower than the prevalence of 39% reported for community-dwelling older individuals. This discrepancy may be explained by selection bias and demographic differences, but raises the possibility of CSH being an age-related epiphenomenon rather than a causal mechanism for syncope, drop attacks and unexplained falls. Our observations have important implications for clinical practice and the development of future research strategies.