Left Ventricular Myocardial Septal Pacing in Close Proximity to LBB Does Not Prolong the Duration of the Left Ventricular Lateral Wall Depolarization Compared to LBB Pacing

Background: Three different ventricular capture types are observed during left bundle branch pacing (LBBp). They are selective LBB pacing (sLBBp), non-selective LBB pacing (nsLBBp), and myocardial left septal pacing transiting from nsLBBp while decreasing the pacing output (LVSP). Study aimed to compare differences in ventricular depolarization between these captures using ultra-high-frequency electrocardiography (UHF-ECG).Methods: Using decremental pacing voltage output, we identified and studied nsLBBp, sLBBp, and LVSP in patients with bradycardia. Timing of ventricular activations in precordial leads was displayed using UHF-ECGs, and electrical dyssynchrony (e-DYS) was calculated as the difference between the first and last activation. The durations of local depolarizations (Vd) were determined as the width of the UHF-QRS complex at 50% of its amplitude.Results: In 57 consecutive patients, data were collected during nsLBBp (n = 57), LVSP (n = 34), and sLBBp (n = 23). Interventricular dyssynchrony (e-DYS) was significantly lower during LVSP −16 ms (−21; −11), than nsLBBp −24 ms (−28; −20) and sLBBp −31 ms (−36; −25). LVSP had the same V1d-V8d as nsLBBp and sLBBp except for V3d, which during LVSP was shorter than sLBBp; the mean difference −9 ms (−16; −1), p = 0.01. LVSP caused less interventricular dyssynchrony and the same or better local depolarization durations than nsLBBp and sLBBp irrespective of QRS morphology during spontaneous rhythm or paced QRS axis.Conclusions: In patients with bradycardia, LVSP in close proximity to LBB resulted in better interventricular synchrony than nsLBBp and sLBBp and did not significantly prolong depolarization of the left ventricular lateral wall.

Del Nido versus HTK cardioplegia for myocardial protection during adult complex valve surgery: a retrospective study

Background Histidine-tryptophan-ketoglutarate (HTK) and del Nido (DN) cardioplegia are intracellular-type and extracellular-type solution respectively, both can provide a long period of myocardial protection with single-dose infusion, but studies comparing the two are rare for adult cardiac surgery. This study aims to evaluate whether DN is suitable for cardioplegia in complex and high-risk valve surgery with long-term cardiac ischemia when compared with HTK. Methods The perioperative records of adult patients infused with DN/HTK as a cardioplegic solution who underwent complex valve surgery with an expected myocardial ischaemic duration longer than 90 min between Oct 2018 and Oct 2019 were analysed retrospectively. Results Of the 160 patients who received DN/HTK and underwent complex valve surgery, we propensity matched 73 pairs. Both groups achieved satisfactory cardiac arrest effects, and no significant difference was found in their cTnI and CK-MB levels within 12 to 72 h postoperatively. The DN group had a higher rate of return to spontaneous rhythm (0.88 v 0.52, P < 0.001), a lower frequency of postoperative severe arrythmias (12% v 26%, P = 0.036), a higher postoperative stroke volume (65 v 59 ml, P = 0.011) and a higher cardiac output (6.0 v 4.9 L/min, P = 0.007) as evaluated by echocardiography, fewer transfusions and shorter ICU stays (both P < 0.05). The two groups had similar inotrope usage and similar incidences of low cardiac output, morbidities and mortality. Subgroup analysis showed that when the aortic clamping time was greater than 120 min, the advantages of DN were weakened. Conclusions DN can be safely applied to complex valve surgery, and it has a similar myocardial protection effect as HTK. Further prospective studies are required to verify these retrospective findings. Trial registration retrospectively registered.

Comparison of Custodiol® and modified St. Thomas cardioplegia for myocardial protection in coronary artery bypass grafting

Background/Aim. Custodiol? is a hyperpolarizing cardioplegic solution which has been used in our national cardiac surgical practice exclusively for the heart transplant surgery. Owing to its numerous advantages over the standard depolarizing solutions, Custodiol? became cardioplegic solution of choice for all other cardiac surgical procedures in many cardio-surgical centers. This study evaluated myocardial protection by Custodiol? compared to modified St. Thomas cardioplegic solution in coronary artery bypass surgery. Methods. In a prospective four-month study, 110 consecutive adult patients who underwent primary isolated elective on-pump coronary artery bypass grafting (CABG) were randomized into the Custodiol? group (n = 54) and the St. Thomas groupa (n = 50), based on the type of administered cardioplegia; six patients were excluded. Cardiac protection was achieved as antegrade cold crystalloid cardioplegia by one of the solutions. Myocardial preservation was assessed through following outcomes: spontaneous rhythm restoration post cross-clamp, and postpoperative cardiac specific enzymes level, ejection fraction (EF) change, inotropic support, myocardial infarction (MI), atrial fibrillation (AF), and death. Results. Preoperative and intraoperative characteristics of patients in both groups were similar except for a considerably longer cross-clamp time in the Custodiol? group (49.1 ? 19.0 vs. 41.0 ? 12.9 minutes; p = 0.022). The Custodiol? group exhibited a higher rate of return to spontaneous rhythm compared to the St. Thomas group (31.5% vs. 20.0%, respectively; p = 0.267), lower rates of AF (20.4% vs. 28%, respectively; p = 0.496), MI (1.8% vs. 10.0%, respectively; p = 0.075) and inotropic support (9.0% vs. 12.0%, respectively; p = 0.651), albeit not statistically significant. There was an insignificant difference in peak value of troponin I between the Custodiol? and Thee St. Thomas group (5.0 ? 3.92 ?g/L vs. 4.5 ? 3.39 ?g/L, respectively; p = 0.755) and creatine kinase-MB (26.9 ? 15.4 ?g/L vs. 28.5 ? 24.2 ?g/L, respectively; p = 0.646) 6 hours post-surgery. EF reduction was comparable (0.81% vs. 1.26%; p = 0.891). There were no deaths in both groups. Conclusions. Custodiol? and modified St.Thomas cardioplegic solution have comparable cardioprotective effects in CABG surgery. The trends of less frequent MI, AF and ino-tropic support, despite the longer cross-clamp time in the Custodiol? group may suggest that its benefits could be ascertained in a larger study.

Outcome of Resynchronization Therapy on Superficial and Endocardial Electrophysiological Findings

Cardiac resynchronization therapy (CRT) has proven efficacious in the treatment of patients with heart failure and dyssynchronous activation. Currently, we select suitable CRT candidates based on the QRS complex duration (QRSd) and morphology with left bundle branch block being the optimal substrate for resynchronization. To improve CRT response rates, recommendations emphasize attention to electrical parameters both before implant and after it. Therefore, we decided to study activation times before and after CRT on the body surface potential maps (BSPM) and to compare thus obtained results with data from electroanatomical mapping using the CARTO system. Total of 21 CRT recipients with symptomatic heart failure (NYHA II-IV), sinus rhythm, and QRSd ≥150 ms and 7 healthy controls were studied. The maximum QRSd and the longest and shortest activation times (ATmax and ATmin) were set in the BSPM maps and their locations on the chest were compared with CARTO derived time interval and site of the latest (LATmax) and earliest (LATmin) ventricular activation. In CRT patients, all these parameters were measured during both spontaneous rhythm and biventricular pacing (BVP) and compared with the findings during the spontaneous sinus rhythm in the healthy controls. QRSd was 169.7±12.1 ms during spontaneous rhythm in the CRT group and 104.3±10.2 ms after CRT (p<0.01). In the control group the QRSd was significantly shorter: 95.1±5.6 ms (p<0.01). There was a good correlation between LATmin(CARTO) and ATmin(BSPM). Both LATmin and ATmin were shorter in the control group (LATmin(CARTO) 24.8±7.1 ms and ATmin(BSPM) 29.6±11.3 ms, NS) than in CRT group (LATmin(CARTO) was 48.1±6.8 ms and ATmin(BSPM) 51.6±10.1 ms, NS). BVP produced shortening compared to the spontaneous rhythm of CRT recipients (LATmin(CARTO) 31.6±5.3 ms and ATmin(BSPM) 35.2±12.6 ms; p<0.01 spontaneous rhythm versus BVP). ATmax exhibited greater differences between both methods with higher values in BSPM: in the control group LATmax(CARTO) was 72.0±4.1 ms and ATmax (BSPM) 92.5±9.4 ms (p<0.01), in the CRT candidates LATmax(CARTO) reached only 106.1±6.8 ms whereas ATmax(BSPM) 146.0±12.1 ms (p<0.05), and BVP paced rhythm in CRT group produced improvement with LATmax(CARTO) 92.2±7.1 ms and ATmax(BSPM) 130.9±11.0 ms (p<0.01 before and during BVP). With regard to the propagation of ATmin and ATmax on the body surface, earliest activation projected most often frontally in all 3 groups, whereas projection of ATmax on the body surface was more variable. Our results suggest that compared to invasive electroanatomical mapping BSPM reflects well time of the earliest activation, however provides longer time-intervals for sites of late activation. Projection of both early and late activated regions of the heart on the body surface is more variable than expected, very likely due to changed LV geometry and interposed tissues between the heart and superficial ECG electrode.

Electrocardiographic Outcome of Resynchronization Therapy

Cardiac resynchronization therapy (CRT) has proven efficacious in reducing or even eliminating cardiac dyssynchrony and thus improving heart failure symptoms. However, quantification of mechanical dyssynchrony is still difficult and identification of CRT candidates is currently based just on the morphology and width of the QRS complex. As standard 12-lead ECG brings only limited information about the pattern of ventricular activation, we aimed to study changes produced by different pacing modes on the body surface potential maps (BSPM). Total of 12 CRT recipients with symptomatic heart failure (NYHA II-IV), sinus rhythm and QRS width ≥120 ms and 12 healthy controls were studied. Mapping system Biosemi (123 unipolar electrodes) was used for BSPM acquisition. Maximum QRS duration, longest and shortest activation times (ATmax and ATmin) and dispersion of QT interval (QTd) were measured and/or calculated during spontaneous rhythm, single-site right- and left-ventricular pacing and biventricular pacing with ECHO-optimized AV delay. Moreover we studied the impact of CRT on the locations of the early and late activated regions of the heart. The average values during the spontaneous rhythm in the group of patients with dyssynchrony (QRS 140.5±10.6 ms, ATmax 128.1±10.1 ms, ATmin 31.8±6.7 ms and QTd 104.3±24.7 ms) significantly differed from those measured in the control group (QRS 93.0±10.0 ms, ATmax 79.1±3.2 ms, ATmin 24.4±1.6 ms and QTd 43.6±10.7 ms). Right ventricular pacing (RVP) improved significantly only ATmax [111.2±10.6 ms (p<0.05)] but no other measured parameters. Left ventricular pacing (LVP) succeeded in improvement of all parameters [QRS 105.1±8.0 ms (p<0.01), ATmax 103.7±7.1 ms (p<0.01), ATmin 20.2±3.7 ms (p<0.01) and QTd 52.0±9.4 ms (p<0.01)]. Biventricular pacing (BVP) showed also a beneficial effect in all parameters [QRS 121.3±8.9 ms (p<0.05), ATmax 114.3±8.2 ms (p<0.05), ATmin 22.0±4.1 ms (p<0.01) and QTd 49.8±10.0 ms (p<0.01)]. Our results proved beneficial outcome of LVP and BVP in evaluated parameters (what seems to be important particularly in the case of activation times) and revealed a complete return of activation times to normal distribution when using these CRT modalities.

Abstract 13327: Prediction of Upcoming Therapeutic Episodes of ICD Through Routine Data in Routine Device Clinic of ICD Patients

Background: Although implantable cardioverter-defibrillator (ICD) prevents sudden death of patients with life-threatening arrhythmia, prediction of upcoming ICD therapy, if possible, would be an important issue in device management. In the present study, the relationship between ICD therapeutic episodes and preceding routine device data was evaluated to clarify the predictors for ICD actuation in near future. Methods: The study population consisted of 100 consecutive ICD patients. All patients were followed up in the device clinic in every 4-month period, and their total follow-up periods of 22.8±4.1 months were divided into 734 4-month observation windows. The common data in device clinic including 12-lead ECG, chest X-ray, and interrogated device data were compared between patients with and without ICD therapeutic episodes during upcoming 4-month windows. To avoid inappropriate weighting on data of specific cases, such as unusual data in cases with frequent shock therapy, sampling number was limited 4-8 times in one case, and all data were evaluated as change during preceding 4 months, e.g., QTc calculated by subtracting 4 month preceding QTc from the recent QTc. Results: During 3.2±1.3 month follow-up, among 734 observation windows, appropriate and inappropriate ICD therapies appeared in 54 (ATP: 29, shock: 25) and 20 (ATP: 11, shock: 9) windows. When the patients were divided into spontaneous rhythm and paced-rhythm groups (n=558 and 170), spontaneous rhythm group did not show any significant difference in parameters between the windows with and without therapeutic episodes. In contrast in paced-rhythm group, RV lead impedance was significantly lower in the windows with therapeutic episodes in comparison with those without (-19.8±43.5Ω vs. 7.4±44.7Ω, p=0.047). Conclusions: Upcoming ICD therapy in near future might be able to be predicted by change in RV lead impedance at least in cases with paced-rhythm in ICD patients. It might reflect the electrical instability in cases with ICD therapeutic episodes.