Real-life experience with non-vitamin K antagonist oral anticoagulants versus warfarin in patients undergoing elective cardioversion of atrial fibrillation.

BACKGROUND: Nonvitamin K antagonist oral anticoagulants (NOACs) are increasingly used in patients with atrial fibrillation (AF) undergoing elective cardioversion (ECV). The aim was to investigate the use of NOACs and warfarin in ECV in a real-life setting and to assess how the chosen regimen affected the delay to ECV and rate of complications. METHODS: Consecutive AF patients undergoing ECVs in the city hospitals of Helsinki between January 2015 and December 2016 were studied. Data on patient characteristics, delays to cardioversion, anticoagulation treatment, acute (<30 days) complications, and regimen changes within one year were evaluated. RESULTS: Nine hundred patients (59.2% men; mean age, 68.0 ± 10.0) underwent 992 ECVs, of which 596 (60.0%) were performed using NOACs and 396 (40.0%) using warfarin. The mean CHA2 DS2 -VASc score was 2.5 (±1.6). In patients without previous anticoagulation treatment, NOACs were associated with a shorter mean time to cardioversion than warfarin (51 versus. 68 days, respectively; p < .001). Six thromboembolic events (0.6%) occurred: 4 (0.7%) in NOAC-treated patients and 2 (0.5%) in warfarin-treated patients. Clinically relevant bleeding events occurred in seven patients (1.8%) receiving warfarin and three patients (0.5%) receiving NOACs. Anticoagulation treatment was altered for 99 patients (11.0%) during the study period, with the majority (88.2%) of changes from warfarin to NOACs. CONCLUSIONS: In this real-life study, the rates of thromboembolic and bleeding complications were low in AF patients undergoing ECV. Patients receiving NOAC therapy had a shorter time to cardioversion and continued their anticoagulation therapy more often than patients on warfarin.

Non-vitamin K antagonist oral anticoagulants in atrial fibrillation patients undergoing elective cardioversion.

Aims: Non-vitamin K antagonist oral anticoagulants (NOAC) have been shown to be safe and effective alternatives to warfarin for the prevention of thromboembolic complications in patients with non-valvular atrial fibrillation (AF). The aim of this study was to investigate the complications and the use of NOACs in AF patients undergoing elective cardioversion. Methods and results: This nationwide multicentre study included consecutive elective cardioversions in AF patients treated with NOACs between October 2011 and May 2016. Data on patient characteristics, antithrombotic treatment and acute (<30 days) complications were collected. One thousand twenty-one patients (mean age 64 years, 70% men) underwent 1291 elective cardioversions, of which 680 (52.7%) cardioversions were performed in patients using dabigatran, 431 (33.4%) rivaroxaban, and 159 (12.3%) apixaban. Mean CHA2DS2-VASc score was 1.8 (±1.5). A total of 3 thromboembolic events occurred after the cardioversion (0.2%): 1 patient receiving dabigatran experienced an ischaemic stroke on Day 2 and 1 rivaroxaban treated patient on Day 4. One patient receiving dabigatran experienced a transient ischaemic attack on Day 11. All 3 patients had used recommended doses of the NOAC. A total of 6 (0.5%) clinically relevant, but not serious bleeding events occurred. Only short duration of AF was associated with lower rate of AF recurrence. Conclusion: Thrombotic and bleeding complications related to NOACs were uncommon (<0.5%) in real life AF patients undergoing elective cardioversion.

[Flatus gone astray and other causes of syncope ]. / Eksynyt pieru ja muita synkopeen syitä.

Loss of consciousness i.e. syncope is a common cause of getting to emergency call service. We describe two patients, in whom fainting was caused by reflexogenic syncope. The diagnosis is quickly solved if there is patience to review the patient history as thoroughly as possible. Registration of the conventional 12-lead electrocardiography and clinical examination usually suffice as basic investigations, without the need for expensive equipment. Careful scrutiny of the medical history will not only reveal the cause of fainting but also the predisposing factors, whereby recurrence of the event can easily be avoided by recognizing a threatening situation early enough.

T-wave morphology after epinephrine bolus may reveal silent long QT syndrome mutation carriers.

BACKGROUND: Long QT syndrome (LQTS) gene mutation carriers with indeterminate electrocardiogram frequently escape clinical diagnosis. We assessed the use of epinephrine bolus injection in revealing T-wave abnormalities. METHODS: We recruited 30 genotyped asymptomatic LQTS gene carriers with nondiagnostic QT interval and 15 controls. Electrocardiogram was recorded with body surface potential mapping after an intravenous epinephrine bolus. T-wave morphology was determined as normal, biphasic, inverted, bifid, or combined pattern. RESULTS: Long QT syndrome carriers and healthy controls had different T-wave profiles (P = .027). Of controls, 12 (80%) of 15 had no change or biphasic appearance, whereas only 10 (33%) of 30 of LQTS carriers had so. Bifid or combined pattern occurred in 15 (50%) of 30 in LQTS and in 6 (60%) of 10 in the LQT3 subgroup but only in 1 (7%) of 15 of healthy. CONCLUSIONS: Modification of ventricular repolarization with low-dose epinephrine injection helps to distinguish silent LQTS mutation carriers. This concerns also the LQT3 subtype, which may escape tests.

Epinephrine bolus test in detecting long QT syndrome mutation carriers with indeterminable electrocardiographic phenotype.

BACKGROUND: In long QT syndrome (LQTS), prolonged and heterogeneous ventricular repolarization predisposes to serious arrhythmias. We examined how QT intervals are modified by epinephrine bolus in mutation carriers of three major LQTS subtypes with indefinite QT interval. METHODS: Genotyped, asymptomatic subjects with LQTS type 1 (LQT1; n = 10; four different KCNQ1 mutations), type 2 (LQT2; n = 10; three different HERG mutations), and type 3 (LQT3; n = 10; four different SCN5A mutations), and healthy volunteers (n = 15) were examined. Electrocardiogram was recorded with body surface potential mapping system. After an epinephrine 0.04 µg/kg bolus QT end, QT apex, and T-wave peak-to-end (Tpe) intervals were determined automatically as average of 12 precordial leads. Standard deviation (SD) of the 12 channels was calculated. RESULTS: Heart rate increased 26 ± 10 bpm with epinephrine bolus, and similarly in all groups. QT end interval lengthened, and QT apex interval shortened in LQTS and normals, leading to lengthening of Tpe interval. However, the lengthening in Tpe was larger in LQTS than in normals (mean 32 vs 18 ms; P < 0.05) and SD of QT apex increased more in LQTS than in normals (mean 23 vs 7 ms; P < 0.01). The increase in Tpe was most pronounced in LQT2, and in SD of QT apex in LQT1 and LQT2. CONCLUSIONS: Abrupt adrenergic stimulation with a moderate dose of exogenous epinephrine affects ventricular repolarization in genotype-specific fashion facilitating distinction from normals. This delicate modification may help in diagnosing electrocardiographically silent mutation carriers when screening LQTS family members.

Abnormal repolarization dynamics revealed in exercise test in long QT syndrome mutation carriers with normal resting QT interval.

AIMS: The identification of affected family members with long QT syndrome (LQTS) is often difficult due to their normal-or only marginally lengthened-QT interval duration. We examined whether physical exercise test could increase the ability to detect the mutation carrier status in phenotypically normal LQTS family members. METHODS AND RESULTS: Sixty-six subjects were included: 15 were carriers of KCNQ1 (LQT1); 15 of KCNH(2) (LQT2); and 9 of SCN5A (LQT3) gene mutations with no, or borderline, QT lengthening; and 27 were healthy controls. Multiple electrograms over the precordial area were recorded during workload and recovery phases of exercise test. QT intervals and T peak to T end intervals (Tpe intervals) were determined using an automatic algorithm at specified heart rates (HR).The LQT1 mutation carriers had QT interval most prolonged during exercise and recovery, whereas the LQT2 carriers had QT interval longest at low exercise HR. The LQT3 carriers had QT interval longest at rest. The Tpe interval remained nearly unchanged during exercise in LQT1, but shortened in LQT2 and in LQT3 carriers. The Tpe interval was longest in LQT2 carriers at the end of the recovery phase. Tentative dichotomizing values of QT and Tpe intervals improved sensitivity and specificity in distinguishing LQTS subtypes, compared with the QT interval duration alone. CONCLUSIONS: LQTS mutation carriers lacking diagnostic QT interval prolongation exhibit abnormal QT and Tpe interval adaptations during physical exercise test. Looking for subtype-specific adaptations might facilitate the identification of LQTS mutation carriers when molecular genetic analysis is not available.

The effect of antihistamine cetirizine on ventricular repolarization in congenital long QT syndrome.

INTRODUCTION: Many drugs are known to block cardiac potassium channels, thus prolonging QT interval and predisposing to malignant arrhythmias. Patients with congenital long QT syndrome are particularly vulnerable, but usually electrophysiological effects of drugs have not been assessed in these patients at risk. METHODS: Fifteen asymptomatic patients with type 1 (LQT1), 15 patients with type 2 (LQT2) long QT syndrome, and 15 healthy volunteers took a placebo and cetirizine 10 mg. In addition, healthy volunteers took cetirizine 50 mg. The study was single-blinded and randomized. Exercise tests were performed during stable plasma concentrations. The electrocardiogram was recorded with a body surface potential mapping system (BSPM). Data were analyzed with an automated analyze program. QT intervals to the T wave apex and T wave end and their difference (Tp-e) were determined at rest and at specified heart rates during and after exercise. RESULTS: Cetirizine did not lengthen the QT intervals at rest or during exercise and recovery in any group. It shortened Tp-e at rest in LQT1 and LQT2 patients and during exercise test in LQT1 patients, thus slightly decreasing electrocardiographic transmural dispersion of repolarization. CONCLUSIONS: Cetirizine does not adversely modify ventricular repolarization in types 1 and 2 long QT syndrome, suggesting that it might be used safely in these long QT syndrome patients.

Effect of physical training on ventricular repolarization in type 1 long QT syndrome: a pilot study in asymptomatic carriers of the G589D KCNQ1 mutation.

AIMS: High-intensity physical exercise and competitive sports have been traditionally avoided in long QT syndrome. However, endurance training increases vagal activity and thus may improve cardiac electrical stability in healthy subjects. We hypothesized that controlled submaximal endurance training would not adversely affect ventricular repolarization in asymptomatic carriers of a KCNQ1 gene mutation of type 1 long QT syndrome (LQT1). METHODS AND RESULTS: Previously, sedentary carriers of a missense mutation of KCNQ1 gene (LQT1, n=7) and healthy controls (n=8) exercised on a bicycle ergometer 3-4 times a week, 30 min a day at 60-75% of maximal heart rate (HR) for a maximum of 3 months. Body surface potential mapping (BSPM) was recorded and QT intervals were determined automatically from 14 channels over the left chest area. Maximal work capacity increased by 4+/-1% in LQT1 and by 14+/-2% in controls (both P<0.05), and left ventricular (LV) mass by 8+/-1% and 9+/-1%, respectively (P<0.05). Resting corrected QT interval shortened by 10+/-1% (P<0.05) and QT interval dispersion by 25+/-9% (P<0.05) in LQT1, but not significantly in controls. QT intervals at specified HRs during workload and recovery phases were not changed in either group. CONCLUSION: In this pilot study of asymptomatic carriers of a KNCQ1 gene mutation, submaximal endurance training did not harmfully affect arrhythmia risk markers. Confirmatory studies in a broader spectrum of LQT1 genotypes are needed before any generalization can be made.

Reproducibility of computerized measurements of QT interval from multiple leads at rest and during exercise.

BACKGROUND: Accurate measurement of the QT interval is important for diagnosing long QT syndrome (LQTS), and in research on determinants of ventricular repolarization time. We tested automatic analysis of QT intervals from multiple ECG leads on chest. METHODS: Eleven healthy volunteers and 10 genotyped LQTS patients were tested at rest and during exercise with a bicycle ergometer twice 1-31 months apart. Electrocardiograms were recorded with the body surface potential mapping system, and 12 precordial channels were selected for analysis. Averaged QT peak and QT end intervals were determined with an automated algorithm, and the difference QT end minus QT peak (Tp-e) was calculated. Repeatability was assessed by coefficient of variation (CV) between measurements. RESULTS: Within one test at rest the QT end intervals were highly repeatable with CV 0.6%. In repeated tests CV was 4.4% for QT end interval and 3.5% when the QT interval was corrected for heart rate. In exercise test at specified heart rates, mean CV was 3.0% for QT end and 2.9% for QT peak interval. The CV of Tp-e interval was 10.2% at rest, and 9.3% in exercise test. Reproducibility was comparable between healthy subjects and LQTS patients. CONCLUSIONS: The BSPM system with automated analysis produced accurate and highly repeatable QT interval measurements. Reproducibility was adequate also over prolonged time periods both at rest and in exercise stress test. The method can be applied in studying duration of ventricular repolarization time in different physiologic and pharmacologic interventions.

Ventricular repolarization and heart rate responses during cardiovascular autonomic function testing in LQT1 subtype of long QT syndrome.

BACKGROUND: In the most prevalent LQT1 form of inherited long QT syndrome symptoms often occur during abrupt physical or emotional stress. Sympathetic stimulation aggravates repolarization abnormalities in experimental LQT1 models. We hypothesized that autonomic function tests might reveal the abnormal repolarization in asymptomatic LQT1 patients. METHODS: We measured heart rates (HRs) and QT intervals in nine asymptomatic carriers of a C-terminal KCNQ1 mutation and 8 unaffected healthy subjects using an approach of global QT values derived from 28 simultaneous electrocardiographic leads on beat-to-beat base during Valsalva maneuver, mental stress, sustained handgrip, and light supine exercise. RESULTS: LQT1 patients exhibited impaired shortening of both QTpeak and QTend intervals during autonomic interventions but exaggerated lengthening of the intervals--a QT overshoot--during the recovery phases. The number of tests with a QT overshoot was 2.4 +/- 1.7 in LQT1 patients and 0.8 +/- 0.7 in unaffected subjects (P = 0.02). Valsalva strain prolonged T wave peak to T wave end interval (TPE) in LQT1 but not in unaffected patients. LQT1 patients showed diminished HR acceleration in response to adrenergic challenge whereas HR responses to vagal stimuli were similar in both groups. CONCLUSIONS: Standard cardiovascular autonomic provocations induce a QT interval overshoot during recovery in asymptomatic KCNQ1 mutation carriers. Valsalva maneuver causes an exaggerated fluctuation of QT and TPE intervals partly explaining the occurrence of cardiac events during abrupt bursts of autonomic activity in LQT1 patients.