Journal: Circulation

Article Title: Autoimmune Atrial Fibrillation

doi: 10.1161/CIRCULATIONAHA.122.062776

Figure Lengend Snippet: Electrophysiological phenotyping of mice with K ir 3.4 autoantibodies. A , Study design of the experimental autoimmune AF model with Balb/c mice. B , Representative surface ECG traces derived from limb leads I and II, recorded from a sham-immunized and K ir 3.4-immunized mouse. C , Bar graphs overlaid with dot plots present mean ECG interval values±SD recorded in sham- (n=14) and K ir 3.4-immunized mice (n=10). Statistical significance was determined using the Student t test (PR, QRS, QTc, and JTc) and Mann-Whitney U test (RR). D , Representative bipolar intracardiac electrogram recordings at the level of the right ventricle (RV) and right atrium (RA). STIM denotes right atrial stimulation. ECG in lead II configuration shows the corresponding surface ECG signals. E , Bar graphs overlaid with dot plots present mean intracardiac electrophysiological data±SD acquired in sham- (n=14) and K ir 3.4-immunized mice (n=10). Statistical significance was determined using the Student t test (SNRT, cSNRT, AERP, and AVERP) and Mann-Whitney U test (WCL). F , Bar graph shows the proportion of sham- (4 of 14) and K ir 3.4-immunized mice (8 of 10) with burst pacing–induced AF. Points indicate mean AF duration±SD ( P =0.214). Statistical significance was determined by Mann-Whitney U test (AF duration), and Fisher exact test was used to assess the induced AF rate. AERP indicates atrial effective refractory period; AF, atrial fibrillation; AVERP, atrioventricular effective refractory period; cSNRT, corrected sinus node recovery time; EGM, electrogram; EPS, electrophysiological study; SNRT, sinus node recovery time; and WCL, Wenckebach cycle length.

Article Snippet: The body temperature was kept at 37 °C with a heating pad, and all mice were continuously monitored with surface 3-lead ECG connected to the data acquisition system PowerLab (16/35, ADInstruments Ltd, United Kingdom).

Techniques: Derivative Assay, MANN-WHITNEY

Journal: Scientific Reports

Article Title: A rat model of complete atrioventricular block recapitulates clinical indices of bradycardia and provides a platform to test disease-modifying therapies

doi: 10.1038/s41598-019-43300-9

Figure Lengend Snippet: Design of electrosurgical needle ablation of the AV node. ( A ) An acupuncture needle and an ECG needle electrode, placed together to form a single unit to deliver electrosurgical energy and to record electrogram at the needle entry site. ( B ) The ablation needle and an ECG needle was assembled together with a polytetrafluoroethylene tape which also provides electrical insulation. The sharp end of the needle was bent at 3–4 mm from the end to limit the needle entry. ( C ) Illustration of the ablation needle, electrosurgical pen contact site, and the ECG electrodes during CAVB procedure. The intracardiac electrogram is recorded from the needle entry site (orange colored negative electrode) to left leg (orange colored positive electrode). ( D ) Needle entry is made through the anatomical landmark, fat pad, pointing toward the LV apex. ( E ) A photograph of the fat pad near the aortic root upon retracting the right atrial appendage.

Article Snippet: This was achieved by attaching the electrode of a surface ECG cable (MLA1203, ADInstrument) to the proximal end of a 0.3 mm diameter, 5 cm long ablation needle (DB106, DongBang Acupuncture, Korea, Fig. ) and insulating them together with polytetrafluoroethylene tape.

Techniques: Insulation

Journal: Scientific Reports

Article Title: A rat model of complete atrioventricular block recapitulates clinical indices of bradycardia and provides a platform to test disease-modifying therapies

doi: 10.1038/s41598-019-43300-9

Figure Lengend Snippet: Surface and epicardial electrocardiograms before and after CAVB creation. ( A ) An example of surface ECG and simultaneous recording of epicardial electrogram under normal sinus rhythm. ( B ) Typical transient ventricular arrhythmias that could be observed during needle entry into the AVN region. ( C ) Upon the needle entry into the proper AVN region, sharp depolarizations starting within the P-wave from the epicardial electrode can be observed from the subepicardial electrogram. Upon successful CAVB, the His-like potentials are no longer observed. ( D ) Long-term follow-up of the CAVB animals demonstrate stable and complete heart block for at least 4 weeks.

Article Snippet: This was achieved by attaching the electrode of a surface ECG cable (MLA1203, ADInstrument) to the proximal end of a 0.3 mm diameter, 5 cm long ablation needle (DB106, DongBang Acupuncture, Korea, Fig. ) and insulating them together with polytetrafluoroethylene tape.

Techniques: Blocking Assay

Journal: Scientific Reports

Article Title: A rat model of complete atrioventricular block recapitulates clinical indices of bradycardia and provides a platform to test disease-modifying therapies

doi: 10.1038/s41598-019-43300-9

Figure Lengend Snippet: Echocardiographic findings before and after CAVB creation. ( A ) A parasternal short axis view (top) and M-mode (bottom) of normal sinus rhythm rat prior to CAVB surgery. ( B ) A parasternal short axis view (top) and M-mode (bottom) of the same rat at one month after CAVB surgery. At one month after CAVB, the left ventricle exhibited severe enlargement compared to the baseline. Mean data from 6 rats are analyzed to compare hemodynamic functions before and one month after CAVB: systolic and diastolic interventricular septum ( C ), LV posterior wall thickness ( D ), LV internal diameter ( E ), LV end systolic volume and end diastolic volume ( F ), LV stroke volume ( G ), LV ejection fraction and LV fractional shortening ( H ), LV mass ( I ). ECG telemetry revealed incidences of spontaneous, non-sustained ventricular tachycardia ( J ) as well as frequent PVCs ( K ) during first few days after CAVB surgery. ( L ) Representative ECG finding after CAVB creation in 3-month old rats. Following AVN ablation, severe ventricular bradycardia was observed (top), followed by non-sustained ventricular tachyarrhythmia (middle), and eventually sudden cardiac arrest (bottom). ( M ) Ventricular arrhythmia inducibility of complete AV block and sham-operated rats. In four out of five CAVB rats, programmed electrical stimulation (PES) induced non-sustained ventricular tachycardia (VT) which degenerated into sustained, polymorphic VT or ventricular fibrillation (VF) upon injection of isoproterenol. In one of the five CAVB rats, VT was induced only when PES was combined with isoproterenol injection. Ventricular arrhythmias were inducible in sham-operated animals only upon isoproterenol injection. One rat exhibited VT and another rat showed non-sustained VT upon PES with isoproterenol injection. Raw traces of PES-non-induced CAVB (top), and PES with isoproterenol-induced VF (bottom) are shown ( N ).

Article Snippet: This was achieved by attaching the electrode of a surface ECG cable (MLA1203, ADInstrument) to the proximal end of a 0.3 mm diameter, 5 cm long ablation needle (DB106, DongBang Acupuncture, Korea, Fig. ) and insulating them together with polytetrafluoroethylene tape.

Techniques: Blocking Assay, Injection

Journal: Scientific Reports

Article Title: A rat model of complete atrioventricular block recapitulates clinical indices of bradycardia and provides a platform to test disease-modifying therapies

doi: 10.1038/s41598-019-43300-9

Figure Lengend Snippet: Focal TBX18 gene transfer to the left ventricular apex of CAVB rats creates ventricular pacing that is faster than the slow junctional rate. ( A ) Timeline of the study indicating creation of CAVB and confirmation of chronic and stable CAVB for 7 days, second thoracotomy and focal injection of Adeno- TBX18 at the left ventricular apex, and a 14-day recording of ECG telemetry. ( B ) Mean heart rates over 2 weeks of TBX18 - or GFP-injected animals. Shaded areas indicate the standard deviation of the heart rate at each time point. ( C ) Surface ECGs from GFP- (top) or TBX18 -injected rat (middle) obtained at the time of and 2 weeks after gene delivery. TBX18 -injected animals often exhibited two competing ventricular rhythms, one presumably from the slow junctional rhythm (arrowhead) and the other due to TBX18 -injection (arrows). ( D ) Heart rate histograms of TBX18 -injected animals show that a second major peak emerges 7 days post gene delivery, which is faster than the slow junctional rhythm. ( E ) Cardiac axis mapping of GFP-injected (left) and TBX18 -injected (right) rats at 7 days post-injection. The faster ventricular rhythm in TBX18 -injected animals exhibits QRS axis change and wider QRS complexes, which indicate retrograde conduction and myocardial depolarization that propagated without the ventricular conduction system, respectively.

Article Snippet: This was achieved by attaching the electrode of a surface ECG cable (MLA1203, ADInstrument) to the proximal end of a 0.3 mm diameter, 5 cm long ablation needle (DB106, DongBang Acupuncture, Korea, Fig. ) and insulating them together with polytetrafluoroethylene tape.

Techniques: Injection, Standard Deviation