Bundle Branch Reentrant Ventricular Tachycardia

Bundle branch reentrant (BBR) tachycardia is an uncommon form of ventricular tachycardia (VT) incorporating both bundle branches into the reentry circuit. The arrhythmia is usually seen in patients with an acquired heart disease and significant conduction system impairment, although patients with structurally normal heart have been described. Surface ECG in sinus rhythm (SR) characteristically shows intraventricular conduction defects. Patients typically present with presyncope, syncope or sudden death because of VT with fast rates frequently above 200 beats per minute. The QRS morphology during VT is a typical bundle branch block pattern, usually left bundle branch block, and may be identical to that in SR. Prolonged His-ventricular (H-V) interval in SR is found in the majority of patients with BBR VT, although some patients may have the H-V interval within normal limits. The diagnosis of BBR VT is based on electrophysiological findings and pacing maneuvers that prove participation of the His- Purkinje system in the tachycardia mechanism. Radiofrequency catheter ablation of a bundle branch can cure BBR VT and is currently regarded as the first line therapy. The technique of choice is ablation of the right bundle. The reported incidence of clinically significant conduction system impairment requiring implantation of a permanent pacemaker varies from 0% to 30%. Long-term outcome depends on the underlying cardiac disease. Patients with poor systolic left ventricular function are at risk of sudden death or death from progressive heart failure despite successful BBR VT ablation and should be considered for an implantable cardiovertor-defibrillator

Timing of life-threatening arrhythmias detected by implantable cardioverter-defibrillators in relation to changes in cosmophysical factors

Background: Studies have linked the natural history of many pathologies with environmental physical activity. This study investigated the relationship between the occurrence of ventricular tachycardia/fibrillation (VT/VF) recorded by implantable cardioverter defibrillators (ICD) and geomagnetic and cosmic ray (neutron) activity. Methods: The study group included 85 patients (73 men) with cardiomyopathy (80% ischemic) who underwent ICD placement in the years 1995&#8211;2006; 74% had a left ventricular ejection fraction of < 30%. Data on the days on which VT/VF occurred (total number of days: 284) and the days on which the patients were treated (total number of treatments: 580) were collected from the ICD records. The findings were analyzed against levels of geomagnetic activity (GMA) (Io&#8211;IVo) and cosmic ray activity (CRA), derived from international observatories, on the same days and throughout the study period. Results: On days of VT/VF, daily values of GMA level averaged 1.5 &#177; 0.7, consistent with level Io (quiet). The ratios of daily VT/VF episodes and treatment to GMA level for the whole study period were as follows: 1.2 level I; 0.9 level II; 0.69 level III; 0.78 level IV (r = &#8211;0.974; p = 0.02). Mean CRA on days of VT/VF was 9246.8 &#177; 299.0 imp/min, and for all 4383 days studied, 8805.33 &#177; 411.4 imp/min (p < 0.0001). Conclusions: In patients with predominantly ischemic cardiomyopathy and severe left ventricular dysfunction, VT/VF occurs more often on days of low GMA and high CRA. Further studies are needed to determine the underlying mechanism of the effect of neutron activity on cardiac electrical instability

Thrombolysis is an effective and safe therapy in stuck bileaflet mitral valves in the absence of high-risk thrombi

AbstractOBJECTIVESWe sought to evaluate the effectiveness and safety of thrombolytic therapy in stuck mitral bileaflet heart valves in the absence of high-risk thrombi.BACKGROUNDCurrent recommendations for the thrombolytic treatment of stuck prosthetic mitral valves are partially based on older valve models and inclusion of patients in whom high-risk thrombi were either ignored or not sought for. The feasibility and safety of thrombolysis in bileaflet models may be affected by the predilection of thrombi to catch the leaflet hinge.METHODSWe studied 12 consecutive patients (men/women = 5/7, age 58.8 ± 14.9 years) who experienced one or more episodes of stuck bileaflet mitral valve over a 33-month period and received thrombolytic therapy with streptokinase, urokinase or tissue-type plasminogen activator. Transesophageal echocardiography was performed in all patients. Patients with mobile or large (>5 mm) thrombi were excluded. Functional class at initial episode was I–II in 4 patients (33.3%) and III–IV in 8 patients (66.6%).RESULTSPatients receiving thrombolytic therapy achieved an overall 83.3% freedom from a repeat operation or major complications (95% confidence interval 51.6–97.9%). Minor bleeding occurred in three patients (25%) and allergic reaction in one (8.3%). Transient vague neurologic complaints, without subjective findings, occurred in four patients (33.3%). Three patients had one or more relapses within 5.2 ± 3.1 months from the previous episode, and readministration of thrombolytics was successful.CONCLUSIONSIn clinically stable patients with stuck bileaflet mitral valves and no high-risk thrombi, thrombolysis is highly successful and safe, both in the primary episode and in recurrence. The best thrombolytic regimen is yet to be established

Groźne dla życia zaburzenia rytmu serca wykrywane przez implantowane kardiowertery-defibrylatory w zależności od zmian czynników kosmofizycznych

Wstęp: W dotychczas przeprowadzonych badaniach powiązano historię naturalną wielu chorób ze środowiskową aktywnością fizyczną. W niniejszej pracy oceniono zależność między występowaniem częstoskurczu komorowego i migotania komór (VT/VF) rejestrowanymi przez implantowane kardiowertery-defibrylatory (ICD) a aktywnością geomagnetyczną i aktywnością promieniowania kosmicznego (neutronowego). Metody: Badana grupa obejmowała 85 pacjentów (w tym 73 mężczyzn) z kardiomiopatią (u 80% osób niedokrwienną), którym wszczepiono ICD w latach 1995-2006. Frakcja wyrzutowa lewej komory wynosiła poniżej 30% u 74% badanych. Dane na temat dni, w których występowały incydenty VT/VF (łączna liczba dni: 284), oraz dni, w których nastąpiło terapeutyczne wyładowanie ICD (łączna liczba leczonych incydentów: 580), uzyskano z zapisów urządzenia. Wyniki przeanalizowano w zależności od aktywności geomagnetycznej (GMA) (I-IV stopień) i aktywności promieniowania kosmicznego (CRA) zmierzonej w międzynarodowych laboratoriach w te same dni oraz w ciągu całego okresu badania. Wyniki: W dniach występowania VT/VF średnia dzienna wartość GMA wynosiła 1,5 &#177; 0,7, co odpowiada I stopniowi aktywności (cisza, niewielka aktywność). Ilorazy prawdopodobieństwa wystąpienia VT/VF w ciągu danego dnia, w zależności od poziomu GMA w całym okresie objętym badaniem wynosiły: 1,2 dla I stopnia aktywności, 0,9 dla II stopnia aktywności, 0,69 dla III stopnia aktywności, 0,78 dla IV stopnia aktywności (r = -0,974; p = 0,02). Średnia wartość CRA w dniach występowania VT/VF wynosiła 9246,8 &#177; 299,0 impulsów na minutę, a w ciągu wszystkich 4383 dni objętych badaniem - 8805,33 &#177; 411,4 impulsów na minutę (p < 0,0001). Wnioski: U pacjentów z kardiomiopatią głównie o charakterze niedokrwiennym oraz z ciężką dysfunkcją lewej komory VT/VF występują częściej w dni charakteryzujące się małą GMA i dużą CRA. Należy przeprowadzić dalsze badania w celu określenia mechanizmów wpływu aktywności neutronów na niestabilność elektryczną serca

Clinical impact of defibrillation testing at the time of implantable cardioverter-defibrillator insertion

Background: Ventricular fibrillation is routinely induced during implantable cardioverter- -defibrillator insertion to assess defibrillator performance, but this strategy is experiencing a progressive decline. We aimed to assess the efficacy of defibrillator therapies and long-term outcome in a cohort of patients that underwent defibrillator implantation with and without defibrillation testing. Methods: Retrospective observational series of consecutive patients undergoing initial defibrillator insertion or generator replacement. We registered spontaneous ventricular arrhythmias incidence and therapy efficacy, and mortality. Results: A total of 545 patients underwent defibrillator implantation (111 with and 434 without defibrillation testing). After 19 (range 9–31) months of follow-up, the death rate per observation year (4% vs. 4%; p = 0.91) and the rate of patients with defibrillator-treated ventricular arrhythmic events per observation year (with test: 10% vs. without test: 12%; p = 0.46) were similar. The generalized estimating equations-adjusted first shock probability of success in patients with test (95%; CI 88–100%) vs. without test (98%; CI 96–100%; p = 0.42) and the proportion of successful antitachycardia therapies (with test: 87% vs. without test: 80%; p = 0.35) were similar between groups. There was no difference in the annualized rate of failed first shock per patient and per shocked patient between groups (5% vs. 4%; p = 0.94). Conclusions: In this observational study, that included an unselected population of patients with a defibrillator, no difference was found in overall mortality, first shock efficacy and rate of failed shocks regardless of whether defibrillation testing was performed or not.Hadid, C.; Atienza, F.; Strasberg, B.; Arenal, Á.; Codner, P.; González-Torrecilla, E.; Datino, T.... (2015). Clinical impact of defibrillation testing at the time of implantable cardioverter-defibrillator insertion. Cardiology Journal. 22(3):253-259. doi:10.5603/Cj.a2014.0062S25325922