Appropriate application of diagnostics for identifying patients in need of pacemaker therapy.

Pacemaker therapy is the cornerstone in treatment of bradycardia and conduction disorders. Several diagnostic tools are utilized to diagnose and guide the physicians for appropriate management and accordingly proper utilization of pacemaker therapy. The current article is discussing the different diagnostics used for appropriate evaluation and diagnosis of bradyarrhythmias and the suggested solutions to improve bradycardia diagnosis and pacemaker therapy utilization in underpenetrated areas.

Isolating the entire pulmonary venous component versus isolating the pulmonary veins for persistent atrial fibrillation: A propensity-matched analysis.

BACKGROUND: The outcomes of pulmonary vein isolation (PVI) for persistent atrial fibrillation (AF) are suboptimal. The entire pulmonary venous component (PV-Comp), consisting of the pulmonary veins, their antra, and the area between the antra, provides triggers and substrate for AF. PV-Comp isolation is an alternative strategy for persistent AF ablation. METHODS: Among 328 patients with persistent AF who underwent a first radiofrequency ablation procedure, 200 patients (PVI, n = 100; PV-Comp isolation, n = 100) were selected by propensity score matching. Both groups were followed up for 1 year. RESULTS: At 6- and 12-month follow-up, atrial tachyarrhythmia (AF/atrial tachycardia) recurred in 41 and 61 patients in PVI group and 22 (P = .006) and 33 patients (P < .001) in PV-Comp isolation group, respectively. PV-Comp isolation was associated with longer mean time to recurrence (PVI: 8 months, PV-Comp isolation: 10 months, log-rank P < .001) and a lower probability of recurrence (odds ratio [OR] = 0.32; 95% confidence of interval [CI] = 0.18-0.56, P < .001), with no increase in procedural complications (PVI: 5 of 100, PV-Comp isolation: 6 of 100, P = .76). Procedure duration was longer in PV-Comp isolation group (PVI: 186 ± 42 min, PV-Comp isolation: 238 ± 44 min, P < .001), as well as fluoroscopy time (PVI: 22 ± 16 min, PV-Comp isolation: 31 ± 21 min, P = .001). CONCLUSION: PV-Comp isolation for persistent AF reduced atrial tachyarrhythmia recurrence up to 1 year compared with PVI alone. While procedure and fluoroscopy time increased, there was no difference in procedural complications.

Anterograde His bundle activation during right ventricular overdrive pacing in supraventricular tachycardia.

BACKGROUND: Differentiation between atrioventricular nodal re-entrant tachycardia (AVNRT), atrioventricular re-entrant tachycardia (AVRT), and atrial tachycardia (AT) is often challenging during electrophysiology studies. This study compared the sensitivity and specificity of identifying anterograde His bundle activation during entrainment with commonly used right ventricular (RV) pacing maneuvers to differentiate between these types of supraventricular tachycardia (SVT). METHODS: Out of 112 consecutive patients with SVT, 90 (36 males [40%], age 37 ± 16 years) were prospectively studied. After entrainment during RV pacing, atrial response upon cessation of pacing, anterograde His activation during entrainment, stimulus-atrial (SA), ventriculoatrial (VA) intervals, and post-pacing interval minus tachycardia cycle length (PPI-TCL) were determined. Ventricular extrastimulation during tachycardia and para-Hisian pacing were performed. RESULTS: The final diagnosis was AVNRT in 54, AVRT in 33, and AT in 3 patients. Entrainment was achieved in 87(96%) patients. Anterograde His bundle activation predicted AVRT (sensitivity: 62.5%, specificity: 100%). PPI-TCL ≥129 ms predicted AVNRT (sensitivity: 83%, specificity: 84%), as did SA-VA value ≥85 ms (sensitivity: 91%, specificity: 87%). Atria were advanced during transition zone in 57% of AVRTs. Atrial pre-excitation in response to progressively premature ventricular extrastimuli identified AVRT (sensitivity: 90%, specificity: 85%). Pre-excitation index ≥87 ms identified AVNRT (sensitivity: 80%, specificity: 100%). Para-Hisian pacing identified AVRT (sensitivity: 25%, specificity: 100%). CONCLUSION: RV pacing maneuvers, applied in isolation, can misclassify a significant proportion of SVTs. Identifying anterograde His bundle activation during entrainment can complement other discriminators in differential diagnosis of SVT, with greatest sensitivity in septal and right-sided accessory pathways.

Assessment of left ventricular mechanical dyssynchrony using real time three-dimensional echocardiography: a comparative study to Doppler tissue imaging.

PURPOSE: To assess left ventricular mechanical dyssynchrony (LVMD) using real time three-dimensional echocardiography (RT3DE) and comparing it with the different dyssynchrony indices derived from Doppler tissue imaging (DTI) for the same patient. METHODS: The study included 60 consecutive patients who were considered candidates for CRT, i.e., having ejection fraction ≤35%, NYHA class III or ambulatory class IV, QRS duration ≥120 msec, on optimal pharmacological therapy. Apical RT3DE full volumes were obtained and analyzed to generate the systolic dyssynchrony index (SDI-16), which is the standard deviation of the time to minimal systolic volume of the 16 segments of LV. Color-coded DTI was performed for the three standard apical views with estimation of the mechanical dyssynchrony index (12 Ts-SD), which is the standard deviation of the time to peak systolic velocity at 12 segments of LV. RESULTS: SDI-16 was 10.96 ± 3.9% (cutoff value: 8.3%), while Ts-SD was 38 ± 10.2 msec (cutoff value: 32.6 msec). The concordance rate for both indices was 75%; however, there was no correlation between both indices (r = 0.14, P = 0.3). SDI-16 showed good correlation with QRS duration (r = 0.45, P < 0.001) and inverse correlation with left ventricular ejection fraction (LVEF) calculated by RT3DE (r =-0.37, P = 0.004), while 12 Ts-SD index showed no correlation with QRS duration (r =-0.0082, P = 0.51) or 2D LVEF (r =-0.26, P = 0.84). CONCLUSIONS: RT3DE can quantify LVMD by providing the SDI-16 and it may prove to be more useful than DTI as it shows increasing dyssynchrony with increased QRS duration and decreased LVEF.

Newer generation cryoballoon vs. contact force-sensing radiofrequency ablation catheter in the ablation of paroxysmal atrial fibrillation.

BACKGROUND: Catheter ablation for atrial fibrillation (AF) has become an effective treatment to control symptoms. The second generation cryoballoon (CB) was designed for more efficient and homogenous freeze. Radiofrequency (RF) ablation catheters using three-dimensional electroanatomical mapping with the use of contact-force radiofrequency (CF RF) technology has achieved good results in several studies. OBJECTIVES: To compare the efficacy and safety of second-generation CB ablation in contrast to CF RF ablation in the ablation of paroxysmal AF. METHODS: A total of 81 consecutive patients suffering from paroxysmal AF underwent pulmonary vein isolation (PVI) either by the second generation cryoballoon (n = 44) or a contact force-sensing RF catheter (n = 37). The study was conducted at Ain Shams University Hospitals and Royal Brompton & Harefield NHS trust. Baseline data, procedural data and patient follow up-at 3, 6 and 12 months-were collected and analysed. RESULTS: The mean age was 53.8 ± 15 years in the CB group and 62.4 ± 12 years in the RF group, females representing 40.9% and 48.6% respectively. The baseline characteristics were comparable, but the CB group had less left atrial diameter and more left ventricular ejection fraction. The CB procedure was shorter (94.4 ± 39.3 vs. 140.8 ± 44.3 min, p < 0.0001), with longer fluoroscopy time (30 vs. 15.1 min, p = 0.047). Procedural complications were comparable between the two groups (CB 4.6%, CF RF 2.7%, p = 0.411). After 1 year, the recurrence rate in the CB group was similar to RF (27.3% vs. 27% respectively, p = 0.980). CONCLUSION: Second-generation CB ablation of paroxysmal AF has similar efficacy and safety to contact force-sensing RF catheters, with shorter procedure times and more fluoroscopy.

Preventive infection control in cardiac device implantation.

BACKGROUND: Cardiac implantable electronic devices have been increasingly used in recent years; as a result, there has been a rise in device-related complications. Pacemaker-associated infection is challenging to manage, including system removal, antimicrobial therapy and reimplantation at another site. The aim of this study was to evaluate adherence to the steps in an infection control protocol in cardiac device implantation. RESULTS: A total of 100 patients referred for cardiac device implantation were enrolled in the study. They were evaluated with regard to the application of infection control measures during device implantation and followed-up for 6 months to detect clinical signs of device-related infection (DRI). A significant correlation was found between the development of postoperative DRI and the presence or absence of the following factors: increasing patient age (p = 0.010), diabetes mellitus (p = 0.024), number of operators ≥4 (p = 0.001), implantation of a biventricular system (p = 0.025), duration of sterilization (p = 0.001), wearing double gloves (p < 0.001) and postoperative hematoma (p = 0.021). CONCLUSIONS: The study identified the following risk factors for DRI: age, diabetes mellitus and cardiac resynchronization therapy system implantation (p = 0.025). Antiseptic measures such as double-glove technique and duration of skin disinfection prior to the procedure, as well as environmental factors, also influenced device infection, as did the number of operators/staff and pocket hematoma.

Early hemodynamic and neurohormonal response after transcatheter aortic valve implantation.

BACKGROUND: The conventional surgical aortic bioprostheses used for treatment of aortic stenosis (AS) are inherently stenotic in nature. The more favorable mechanical profile of the Medtronic CoreValve bioprosthesis may translate into a better hemodynamic and neurohormonal response. PATIENTS AND METHODS: The early hemodynamic and neurohormonal responses of 56 patients who underwent successful transcatheter aortic valve implantation (TAVI) using the Medtronic CoreValve bioprosthesis for severe symptomatic AS were compared with those of 36 patients who underwent surgical aortic valve replacement (SAVR) using tissue valves in the same period. RESULTS: At baseline, patients in the TAVI and SAVR group had comparable indexed aortic valve area (0.33 ± 0.1 vs 0.34 ± 0.1 cm² , respectively; P = .69) and mean transvalvular gradient (51.1 ± 16.5 vs 53.1 ± 14.3 mm Hg, respectively; P = .56). At 30-day follow-up, mean transvalvular gradient was lower in the TAVI group than in the SAVR group (10.3 ± 4 vs 13.1 ± 6.2 mm Hg, respectively; P = .015), and the indexed aortic valve area was larger in the TAVI group (1.0 ± 0.14 vs 0.93 ± 0.13 cm²/m²; P = .017). There was a trend toward a higher incidence of moderate patient-prosthesis mismatch in the surgical group compared with the TAVI group (30.5% vs 17.8%, respectively; P = .11). The overall incidence of prosthetic regurgitation (any degree) was higher in the TAVI group than in the SAVR group (85.7% vs 16.7%, respectively; P < .00001). The left ventricular mass index decreased after TAVI (175.1 ± 61.8 vs 165.6 ± 57.2 g/m²; P = .0003) and remained unchanged after SAVR (165.1 ± 50.6 vs 161 ± 64.8 g/m²; P = .81). Similarly, NT-ProBNP decreased after TAVI (3,479 ± 2,716 vs 2,533 ± 1,849 pg/mL; P = .033) and remained unchanged after SAVR (1,836 ± 2,779 vs 1,689 ± 1,533 pg/mL; P = .78). There was a modest correlation between natriuretic peptides and left ventricular mass index in the whole cohort (r = 0.4, P = .013). CONCLUSION: In patients with severe AS, TAVI resulted in lower transvalvular gradients and higher valve areas than SAVR. Such hemodynamic performance after TAVI may have contributed to early initiation of a reverse cardiac remodeling process and a decrease in natriuretic peptides.

Ivabradine, a novel heart rate slower: is it a sword of double blades in patients with idiopathic dilated cardiomyopathy?

OBJECTIVE: To prospectively assess the safety and efficacy of ivabradine in patients with idiopathic dilated cardiomyopathy. METHODS: We included 35 patients with idiopathic dilated cardiomyopathy with an ejection fraction (EF) <40% and heart rate >70 beats/min despite optimal medical therapy, according to the international guidelines in this prospective, non-randomized, single-arm, open-label safety study. Ivabradine was used as an add-on therapy to the maximally tolerated b-blocker in an increasing titrated dose till a target dose of 15 mg/day or resting heart rate of 60 beats/min for 3 months. During follow-up period the safety, patient tolerance and efficacy of this drug were assessed. All patients underwent 12-lead resting electrocardiography and Holter monitoring at inclusion and after 3 months. Statistical analysis was accomplished using paired t-test and Pearson correlation analysis. RESULTS: We found a significant reduction in the resting heart rate by a mean of 25.9 ± 9.4%, without a significant change of blood pressure. There was no prolongation of PR, QTc or QRS durations. Ventricular ectopic activity showed significant reduction (p<0.001). There was a significant correlation between the resting heart rate, NYHA and left ventricular ejection fraction (p<0.001 for both). One patient developed photopsia and decompensation was observed in another patient. CONCLUSION: Ivabradine is a safe and effective drug in reducing resting heart rate, improving NYHA functional class without undesirable effects on conduction parameters or ectopic activity.