Lazar Angelkov

Contractile reserve assessed by dobutamine test identifies super-responders to cardiac resynchronization therapy.

Introduction In this study, we sought to determine whether myocardial contractile reserve (CR) assessed by dobutamine stress echocardiography (DSE) can identify patients who experience nearly complete normalization of left ventricular (LV) function after the implantation of a cardiac resynchronization therapy (CRT) pacemaker. Material and methods The study group consisted of 55 consecutive patients with non-ischemic dilated cardiomyopathy, LV ejection fraction (LVEF) < 35%, and prolonged QRS complex duration, who were scheduled for CRT pacemaker implantation. The DSE (20 µg/kg/min) was performed in all patients. The CR assessment was based on a change in the wall motion score index (ΔWMSI) and ΔLVEF during DSE. Super-response was defined as an increase in LVEF to > 50% and reduction in left ventricular end-systolic dimension to < 40 mm 12 months following the CRT implantation. Results A total of 7 patients (12.7%) were identified as super-responders to CRT. When compared to non-super-responders, these patients had significantly higher values of the dobutamine-induced change in ΔWMSI (1.031 ±0.120 vs. 0.49 ±0.371, p < 0.01), and ΔEF (17.9 ±2.2 vs. 8.8 ±6.2, p < 0.01). Receiver operating characteristic analysis showed that dobutamine-induced changes in ΔWMSI ≥ 0.7 and ≥ 14% for ΔEF are the best discriminators for a super-response. Patients with ΔWMSI ≥ 0.7 and ΔEF ≥ 14% are significantly less often hospitalized (p < 0.01) for worsening of heart failure during 28.5 ±3.0 months of the follow-up. Conclusions Contractile reserve assessed by DSE can identify patients with dilated cardiomyopathy who are likely to experience near normalization of LV function following CRT.

Impact of concomitant aortic regurgitation on long-term outcome after surgical aortic valve replacement in patients with severe aortic stenosis

BackgroundPrognostic value of concomitant aprtic regurgitation (AR) in patients operated for severe aortic stenosis (AS) is not clarified. The aim of this study was to prospectively examine the impact of presence and severity of concomitant AR in patients operated for severe AS on long-term functional capacity, left ventricular (LV) function and mortality.MethodsStudy group consisted of 110 consecutive patients operated due to severe AS. The patients were divided into AS group (56 patients with AS without AR or with mild AR) and AS+AR group (54 patients with AS and moderate, severe or very severe AR). Follow-up included clinical examination, six minutes walk test (6MWT) and echocardiography 12 and 104 months after AVR.ResultsPatients in AS group had lower LV volume indices throughout the study than patients in AS+AR group. Patients in AS group did not have postoperative decrease in LV volume indices, whereas patients in AS+AR group experienced decrease in LV volume indices at 12 and 104 months. Unlike LV volume indices, LV mass index was significantly lower in both groups after 12 and 104 months as compared to preoperative values. Mean LVEF remained unchanged in both groups throughout the study. NYHA class was improved in both groups at 12 months, but at 104 months remained improved only in patients with AS. On the other hand, distance covered during 6MWT was longer at 104 months as compared to 12 months only in AS+AR group (p = 0,013), but patients in AS group walked longer at 12 months than patients in AS+AR group (p = 0,002). There were 30 deaths during study period, of which 13 (10 due to cardiovascular causes) in AS group and 17 (12 due to cardiovascular causes) in AS+AR group. Kaplan-Meier analysis showed that the survival probability was similar between the groups. Multivariate analysis identified diabetes mellitus (beta 1.78, p = 0.038) and LVEF < 45% (beta 1.92, p = 0.049) as the only independent predictor of long-term mortality.ConclusionOur data indicate that the preoperative presence and severity of concomitant AR has no influence on long-term postoperative outcome, LV function and functional capacity in patients undergoing AVR for severe AS.

Wireless remote monitoring of reconstructed 12-lead ECGs after ablation for atrial fibrillation using a hand-held device

OBJECTIVE Atrial fibrillation (AF) surveillance using a wireless handheld monitor capable of 12-lead electrocardiogram reconstruction was performed, and arrhythmia detection rate was compared with serial Holter monitoring. METHODS Twenty-five patients were monitored after an AF ablation procedure using the hand-held monitor for 2 months immediately after and then for 1 month approximately 6 months postablation. All patients underwent 12-lead 24-hour Holter monitoring at 1, 2, and 6 months postablation. RESULTS During months 1-2, 425 of 2942 hand-held monitor transmissions from 21 of 25 patients showed AF/atrial flutter (Afl). The frequency of detected arrhythmias decreased by month 6 to 85/1128 (P < .01) in 15 of 23 patients. Holter monitoring diagnosed AF/Afl in 8 of 25 and 7 of 23 patients at months 1-2 and month 6, respectively (P < .01 compared with wireless hand-held monitor). Af/Afl diagnosis by wireless monitoring preceded Holter detection by an average of 24 days. CONCLUSIONS Wireless monitoring with 12-lead electrocardiogram reconstruction demonstrated reliable AF/Afl detection that was more sensitive than serial 12-lead 24-hour Holter monitoring.

Feasibility of semi-quantitative assessment of left ventricular contractile reserve in dilated cardiomyopathy

We and others have shown previously that left ventricular (LV) contractile reserve assessed quantitatively by high‐dose dobutamine stress‐echocardiography (DSE) has prognostic implications in patients with dilated cardiomyopathy.

Spontaneous Ventricular Arrhythmias Following Partial Left Ventriculectomy for Nonischemic Dilated Cardiomyopathy: Relation to Hemodynamics and Survival

The study assessed the value of ambulatory electrocardiogram (AECG) monitoring for identification of patients who are at increased risk for cardiac death or arrhythmic event following partial left ventriculectomy (PLV). Furthermore, the impact of PLV and its hemodynamics on the occurrence of spontaneous ventricular arrhythmias was assessed in long‐term survivors. In 32 idiopathic dilated cardiomyopathy patients who underwent PLV, ambulatory ECG (AECG) was performed preoperatively, early postoperatively, and 6 months and 12 months after surgery. In 17 of 19 patients who survived > 12 months after the procedure, left ventricular (LV) angiography was performed at the same time points and was used to calculate LV ejection fraction, and end‐diastolic and end‐systolic wall stress. During a mean follow‐up of 478 ± 405 days, 11 cardiac events occurred. Cox univariate regression revealed frequency of premature ventricular contractions > 30/hour at baseline (p = 0.0213) and duration of heart failure symptoms (p = 0.0226) as predictors of cardiac death or arrhythmic event after PLV. In a multivariate analysis, only frequency of premature ventricular contractions > 30/hour was a significant predictor. There was no change in the frequency or severity of ventricular arrhythmias after PLV. However, frequency of premature ventricular contractions correlated with LV end‐diastolic stress (r = 0.35, p = 0.013), and ejection fraction (r =−0.34, p = 0.016). Preoperative AECG monitoring may help stratification of PLV patients. Serial AECG did not show that PLV influence the incidence or the complexity of spontaneous ventricular arrhythmias. In contrast, it appears that a hemodynamically “successful” procedure may decrease the incidence of ventricular arrhythmias.

Location of accessory pathways and its radiofrequency ablation in Wolf-Parkinson-White syndrome

INTRODUCTION Radiofrequency ablation (RFA) of accessory pathways (AP) is the first line therapy in symptomatic patients with preexcitation syndrome, resistant to medical therapy. OBJECTIVE To evaluate the influence of AP location on RFA effectiveness. METHOD The study compared RFA results of AP located on the left side, right side, and in septal area of the heart in the first 101 consecutive patients treated at Dedinje Cardiovascular Institute in Belgrade. RESULTS There was no significant difference between the right-, left- and septal-AP in relation to primary success rates (66.7%, 84.3%, 73.7%, respectively, p = 0.285), recurrence rates (12.5%, 6.97%, 14.3%, p = 0.591), and final success rates (66%, 84.3%, 78.9%, p = 0.37). Maximally achieved interface temperature was lowest at right-sided AP (49.8 +/- 1.9 degrees C) as compared to the left (53.0 +/- 3.5 degrees C) or septal AP (52.9 +/- 3.0 degrees C) (p < 0.01). Fluoroscopy time did not differ significantly (p = 0.062), while total procedure time and the number of applied RF pulses was higher in the left-sided AP as compared to other two (104.6 +/- 44.9 for the left, 98.9 +/- 47.5 for the right and 80.7 +/- 39.8 minutes for the septal AP, p < 0.05; 11.0 +/- 8.8 pulses for the left, 6.5 +/- 3.8 for the right and 6.4 +/- 5.0 for septal AP, p < 0.01). Two major complications developed: one third-degree AV block after ablation of midseptal AP, and one pericardial effusion without tamponade, with spontaneous regression. CONCLUSION The success rate of RFA of the right-, left- and septal-AP was similar. Heating of the tissue was weakest during RFA of the right-sided AP.

Acute Effects of DDD Pacing in Patients With Pulmonary Infundibular Stenosis

We evaluated acute effects of DDD pacing (right atrium sensed and left ventricle paced) in 3 patients with pulmonary infundibular stenosis and found a decrease in dynamic right ventricular outflow gradient in all of them. It appears that acute temporary DDD pacing may decrease the dynamic obstruction of the right ventricular outflow tract in these patients, probably because of asynchronous contraction of the right ventricle induced by pacing from the left ventricular apex, with contraction of infundibular portion being delayed.

Wireless monitoring of reconstructed 12-lead ECG in atrial fibrillation patients enables differential diagnosis of recurrent arrhythmias

Differential diagnosis of symptomatic events in post-ablation atrial fibrillation (AF) patients (pts) is important; in particular, accurate, reliable detection of AF or atrial flutter (AFL) is essential. However, existing remote monitoring devices usually require attached leads and are not suitable for prolonged monitoring; moreover, most do not provide sufficient information to assess atrial activity, since they generally monitor only 1–3 ECG leads and rely on RR interval variability for AF diagnosis. A new hand-held, wireless, symptom-activated event monitor (CardioBip; CB) does not require attached leads and hence can be conveniently used for extended periods. Moreover, CB provides data that enables remote reconstruction of full 12-lead ECG data including atrial signal information. We hypothesized that these CB features would enable accurate remote differential diagnosis of symptomatic arrhythmias in post-ablation AF pts. Methods: 21 pts who underwent catheter ablation for AF were instructed to make a CB transmission (TX) whenever palpitations, lightheadedness, or similar symptoms occurred, and at multiple times daily when asymptomatic, during a 60 day post-ablation time period. CB transmissions (TXs) were analyzed blindly by 2 expert readers, with differences adjudicated by consensus. Results: 7 pts had no symptomatic episodes during the monitoring period. 14 of 21 pts had symptomatic events and made a total of 1699 TX, 164 of which were during symptoms. TX quality was acceptable for rhythm diagnosis and atrial activity in 96%. 118 TX from 10 symptomatic pts showed AF (96 TX from 10 pts) or AFL (22 TX from 3 pts), and 46 TX from 9 pts showed frequent PACs or PVCs. No other arrhythmias were detected. Five pts made symptomatic TX during AF/AFL and also during PACs/PVCs. Conclusions: Use of CB during symptomatic episodes enabled detection and differential diagnosis of symptomatic arrhythmias. The ability of CB to provide accurate reconstruction of 12 L ECGs including atrial activity, combined with its ease of use, makes it suitable for long-term surveillance for recurrent AF in post-ablation patients.

Transseptal approach to the implantation of cardiac resynchronization therapy

Introduction. In patients with cardiac resynchronization therapy left ventricular lead is usually placed through a tributary vein of the coronary sinus. However, when this approach failed, the atrial transseptal approach is mostly used for endovascular left ventricular lead placement, but it is quite difficult to perform. Case report. 59-years-old patient, male, was hospitalized due to endovascular left ventricular lead placement by atrial transseptal approach, after failed attempt via coronary sinus vein. Nonischemic dilated cardiomiopathy was verified 1 year ago. Endoventricular lead was introduced by left subclavian approach and advanced through the previously punctured hole in the left atrium cavity and over mitral valve placed in posterolateral part of left ventricular. Both right ventricular defibrillator lead and atrial electrode were implanted routinely in the right ventricle septum and right atrial appendage. Conclusion. Left ventricular endocardial lead implantation by atrial transseptal approach is a feasible and safe in patients with previously failed implantation via tributary vein of the coronary sinus.

Emotional stress as a cause of syncope and torsade de pointes in patients with long QT syndrome.

INTRODUCTION Long QT syndrome (LQTS) is a disorder of myocardial repolarization characterized by the prolongation of QT interval and high risk propensity of torsade de pointes (TdP) that can lead to syncope, cardiac arrest and sudden death. Episodes may be provoked by various stimuli depending on the type of the condition. CASE REPORT A 25-year-old famele patient was hospitalized due to syncope that occurred immediately after her solo concert, first time in her life. The patient studied solo singing and after intensive preparations the first solo concert was organized. Electrocardiography (ECG) on admission registered frequent ventricular premature beats (VES), followed by polymorphic ventricular tachycardia--TdP that degenerated into ventricular fibrilation (VF). After immediate cardioversion magnesium and beta-blockers were administered. TdP was registered again several times preceded by VES. The corrected QT interval (QTc) was 516 msec. For secondary prevention of sudden cardiac death, a cardioverter defibrillator was implanted, and beta-blockers continued. After a 1-year follow-up there were no recurrent episodes of TdP, and measured QTc was reduced to 484 msec. CONCLUSION Patients with syncope following intensive emotional stress should be evaluated for malignant arrhythmias in the context of LQTS.