Jan Ruta

Metoprolol succinate vs. ivabradine in the treatment of inappropriate sinus tachycardia in patients unresponsive to previous pharmacological therapy

AIMS Inappropriate sinus tachycardia (IST) is a clinical syndrome characterized by excessive resting heart rate (HR) or disproportional increasing HR during exercise. The treatment of IST symptoms using beta-blockers or calcium channel-blockers is often non-effective or not well tolerated. Ivabradine is a new agent inhibiting sinus node I(f) current, resulting in a decrease of HR without haemodynamic compromise. METHODS AND RESULTS We enrolled 20 patients (36 ± 10 years; 14 women) affected by IST and resistant to previous administered therapy by using beta-blockers or verapamil. After 4 weeks of treatment with metoprolol succinate (up to 190 mg once a day) the therapy was switched to ivabradine up to 7.5 mg twice daily. Holter monitoring and treadmill stress test were performed after 1 and 2 months following start of the study. We observed a significant reduction of resting HR both for metoprolol and for ivabradine compared with baseline (92.8 vs. 90.2 vs. 114.3 b.p.m.; P< 0.001). During daily activity there was an even larger decrease of HR on ivabradine (mean daytime HR 94.6 vs. 87.1 vs. 107.3 b.p.m.; P< 0.001). Ivabradine was very well tolerated whereas in 10 patients on metoprolol we observed hypotension or bradycardia requiring dose reduction. Significantly lower incidence of IST-related symptoms were registered on ivabradine therapy than on metoprolol. Fourteen patients (70%) treated with I(f) blocker were free of IST-related complaints. CONCLUSIONS Metoprolol and ivabradine exert a similar effect on resting HR in patients with IST. Ivabradine seems to be more effective to relieve symptoms during exercise or daily activity.

Poincare mapping for detecting abnormal dynamics of cardiac repolarization

This article concentrates on analysis of subtle ECG signal features associated with characteristic temporal variations in the repolarization phase of cardiac electrical activation (i.e., variations that are embedded within the T-wave). These variations are termed T-wave alternans (TWA) to connote larger similarity between T-wave shapes in every other beat than that in the adjacent beats that occur during regular heart rhythm of an increased rate. In an early work the concept of associating TWA with period-doubling bifurcation of the cardiac oscillator has been put forward and demonstrated on canine ECG traces. In this article we extend this idea and use it for quantification of TWA in human ECGs recorded from postinfarction patients. The purpose of this work is to show that: a statistically significant correlation exists for the analyzed ECGs between the TWA level computed by means of an inter-cycle synchronized sampling technique known as Poincare mapping (PM) and a widely used Fourier spectrum (FS) method, and that the PM method outperforms the widely used FS method for TWA analysis in a number of ways.

P Wave Dispersion and P Wave Duration on SAECG in Predicting Atrial Fibrillation in Patients with Acute Myocardial Infarction

Background: Atrial fibrillation (AF) is a frequent complication of acute myocardial infarction (AMI), with reported incidence of 7% to 18%. The incidence of congestive heart failure, in‐hospital mortality, and long‐term mortality is higher in AMI patients with AF than in AMI patients without AF. P wave duration on signal‐averaged ECG (PWD) and P wave dispersion on standard ECG (Pd) are noninvasive markers of intra‐atrial conduction disturbances, which are believed to be the main electrophysiological cause of AF.

Ivabradine in Combination With Metoprolol Succinate in the Treatment of Inappropriate Sinus Tachycardia

Background: Inappropriate sinus tachycardia (IST) is a clinical syndrome characterized by excessive resting heart rate (HR) or a disproportional increase in HR during exercise. β-blocker or calcium channel-blocker therapy is often noneffective or not well tolerated. The HR reduction on ivabradine is similar to β-blockers but in some patients its efficacy to resolve all IST-related symptoms is limited. The aim of the study was to assess the efficacy and safety of combining ivabradine with metoprolol succinate in patients with refractory highly symptomatic IST. Methods: Twenty patients (36 ± 10 years; 16 women) with IST were enrolled. All patients received metoprolol succinate 95 mg single dose during the first month of the study. After 4 weeks of treatment with metoprolol, ivabradine was administered as adjuvant therapy up to 7.5 mg twice daily. Holter monitoring and treadmill stress test were performed at baseline, after 4, and 8 weeks of the study, respectively. Results: We observed significant and similar reduction in resting HR both for metoprolol and for combined therapy compared to the baseline. The mean HR during daily activity was significantly lower on ivabradine and metoprolol compared to monotherapy with β-blocker. The combined treatment yielded a significant increase in exercise capacity as assessed by treadmill stress test. After 4 weeks of combined therapy a significant reduction in IST-related symptoms, measured by means of the European Heart Rhythm Association score, was observed. Conclusion: Combining ivabradine with metoprolol is an effective and well-tolerated treatment option for IST in patients with refractory to monotherapy.

Computer Software tool for heart rate variability (HRV), T-wave alternans (TWA) and heart rate turbulence (HRT) analysis from ECGs

Summary Background This paper presents a software package for quantitative evaluation of heart rate variability (HRV), heart rate turbulence (HRT), and T-wave alternans (TWA) from ECG recordings. The software has been developed for the purpose of scientific research rather than clinical diagnosis. Material/Methods The software is written in Matlab Mathematical Language. Procedures for evaluation of HRV, HRT and TWA were implemented. HRV analysis was carried out by applying statistical and spectral parametric and nonparametric methods. HRT parameters were derived using the Schmidt algorithm. TWA analysis was performed both in spectral and in time domain by applying Poincare mapping. A flexibility of choosing from a number of classical modelling approaches and their modifications was foreseen and implemented. The software underwent preliminary verification tests both on ECGs from the Physionet online ECG signal repository and recordings taken at the Department of Electrocardiology of the Medical University Hospital in Lodz. Results The result of the research is a program enabling simultaneous analysis of a number of parameters computed from ECG recordings with the use of the indicated analysis methods. The program offers options to preview the intermediate results and to alter the preprocessing steps. Conclusions By offering the possibility to cross-validate the results of analyses obtained by several methods and to preview the intermediate analysis steps, the program can serve as a helpful aid for clinicians in comprehensive research studies. The software tool can also be utilized in training programs for students and medical personnel.

A New Type of Dual Atrioventricular Nodal Nonreentrant Tachycardia

Dual atrioventricular nodal nonreentrant tachycardia (DAVNNT) is very rarely observed clinically. The first review of this arrhythmia was published in 2011 by Wang, where four types of DAVNNT were described. Our case report presents a phenomenon that has never been published before. We revealed a very specific sequence of double fire phenomenon, 1:1 atrioventricular (AV) conduction and AV block.

Abnormal filter setting or Brugada syndrome

26-year old patient was admitted to our department with suspected Brugada syndrome (BrS). He complained of recurrent dizziness due to which he was taken by a team of rescuers to the district hospital, where the recorded ECG demonstrated isolated 3–7 mm ST segment elevation in leads V1–V3. Coronary angiography performed in this hospital was normal. Then patient was transferred to our department for consideration of ICD implantation. ECG registration in our hospital with 0.05 Hz (3.2 s) filter showed sinus bradycardia with 1–2 mm ST segment elevation in precordial leads. A detailed analysis of all ECGs proved that the district hospital ECG was performed in manual mode with the application of 1.5 Hz (0.1 s) low frequency high-pass filter. To confirm the effect of incorrect filter as the cause of misdiagnosis we repeated ECG recording using the recorder which allows to apply the same settings 1.5 Hz (0.1 s) as in district hospital and reconstructed ECG with repolarisation abnormalities. Negative ajmaline test (1 mg/kg) additionally reaffirmed an exclusion of dynamic form of BrS.

Relationship Between Changes in Pulse Pressure and Frequency Domain Components of Heart Rate Variability During Short-Term Left Ventricular Pacing in Patients with Cardiac Resynchronization Therapy

Background The aim of the study was to explore the relationship between changes in pulse pressure (PP) and frequency domain heart rate variability (HRV) components caused by left ventricular pacing in patients with implanted cardiac resynchronization therapy (CRT). Material/Methods Forty patients (mean age 63±8.5 years) with chronic heart failure (CHF) and implanted CRT were enrolled in the study. The simultaneous 5-minute recording of beat-to-beat arterial systolic and diastolic blood pressure (SBP and DBP) by Finometer and standard electrocardiogram with CRT switched off (CRT/0) and left ventricular pacing (CRT/LV) was performed. PP (PP=SBP-DBP) and low- and high-frequency (LF and HF) HRV components were calculated, and the relationship between these parameters was analyzed. Results Short-term CRT/LV in comparison to CRT/0 caused a statistically significant increase in the values of PP (P<0.05), LF (P<0.05), and HF (P<0.05). A statistically significant correlation between ΔPP and ΔHF (R=0.7384, P<0.05) was observed. The ΔHF of 6 ms2 during short-term CRT/LV predicted a PP increase of ≥10% with 84.21% sensitivity and 85.71% specificity. Conclusions During short-term left ventricular pacing in patients with CRT, a significant correlation between ΔPP and ΔHF was observed. ΔHF ≥6 ms2 may serve as a tool in the selection of a suitable site for placement of a left ventricular lead.

Potential benefit of optimizing atrioventricular & interventricular delays in patients with cardiac resynchronization therapy

Background & objectives: The clinical benefit of optimization (OPT) of atrioventricular delay (AVD) and interventricular delay (VVD) in cardiac resynchronization therapy (CRT) remains debatable. This study was aimed to determine the influence of AVD and VVD OPT on selected parameters in patients early after CRT implantation and at mid-term follow up (FU). Methods: Fifty two patients (61±10 yr, 23 males) with left bundle branch block, left ventricular ejection fraction (LVEF) ≤35 per cent and heart failure were selected for CRT implantation. Early on the second day (2DFU) after CRT implantation, the patients were assigned to the OPT or the factory setting (FS) group. Haemodynamic and electrical parameters were evaluated at baseline, on 2DFU after CRT and mid-term FU [three-month FU (3MFU)]. Echocardiographic measures were assessed before implantation and at 3MFU. The AVD/VVD was deemed optimal for the highest cardiac output (CO) with impedance cardiography (ICG) monitoring. Results: On 2DFU, the AVD was shorter in the OPT group, LV was paced earlier than in FS group and CO was insignificantly higher in OPT group. At 3MFU, improvement of CO was observed only in OPT patients, but the intergroup difference was not significant. At 3MFU in OPT group, reduction of LV in terms of LV end-diastolic diameter (LVeDD), LV end-systolic diameter, LV end-diastolic and systolic volume with the improvement in LVEF was observed. In FS group, only a reduction in LVeDD was present. In OPT group, the paced QRS duration was shorter than in FS group patients. Interpretation & conclusions: CRT OPT of AVD and VVD with ICG was associated with a higher CO and better reverse LV remodelling. CO monitoring with ICG is a simple, non-invasive tool to optimize CRT devices.

Zablokowane ExSV czy pojedyncze pobudzenia nawrotne? Jeden zapis, dwie interpretacje

This article presents a case of a young female patient with a history of paroxysmal supraventricular tachycardia subjected to electrophysiology study and an atrioventricular node slow pathway ablation. The 24-hour Holter ECG monitoring was performed the day after the procedure. According to the authors ECG recording can be equally interpreted in two ways — as blocked premature atrial beats or retrograde atrial activation.