[Pacemaker optimization guided by echocardiography in cardiac resynchronization therapy]. / Ehokardiografski bodjena optimizacija rada pejsmejkera kod resinhronizacione terapije slabosti srca.

INTRODUCTION: Cardiac resynchronization therapy (CRT) or biventricular pacing is a contemporary treatment in the management of advanced heart failure. Echocardiography plays an evolving and important role in patient selection for CRT, follow-up of acute and chronic CRT effects and optimization of device settings after biventricular pacemaker implantation. In this paper we illustrate usefulness of echocardiography for successful AV and VV timing optimization in patients with CRT. A review of up-to-date literature concerning rationale for AV and VV delay optimization, echocardiographic protocols and current recommendations for AV and VV optimization after CRT are also presented. OUTLINE OF CASES: The first case is of successful AV delay optimization guided by echocardiography in a patient with dilated cardiomyopathy treated with CRT is presented. Pulsed blood flow Doppler was used to detect mitral inflow while programming different duration of AV delay. The AV delay with optimal transmittal flow was established. The optimal mitral flow was the one with clearly defined E and A waves and maximal velocity time integral (VTI) of the mitral flow. Improvement in clinical status and reverse left ventricle remodelling with improvement of ejection fraction was registered in our patient after a month. The second case presents a patient with heart failure caused by dilated cardiomyopathy; six months after CRT implantation the patient was still NYHA class III and with a significantly depressed left ventricular ejection fraction. Optimization of VV interval guided by echocardiography was undertaken measuring VTI of the left ventricular outflow tract (LVOT) during programming of different VV intervals. The optimal VV interval was determined using a maximal LVOT VTI. A month after VV optimization our patient showed improvement in LV ejection fraction. CONCLUSION: Optimal management of patients treated with CRT integrate both clinical and echocardiographic follow-up with, if needed, echocardiographically guided optimization of AV and VV delays, which offers the possibility of additional clinical improvement in such patients.

[New echocardiographic tehniques in optimal patient selection for cardiac resynchronization therapy in the treatment of chronic heart failure].

Cardiac resynchronization therapy (CRT) has important role in the contemporary treatment of heart failure, systolic dysfunction and mechanical disynchrony. Classical indications for CRT are severe heart failure (NYHA class IlI or IV), a broad QRS (more than 120 ms) and left ejection fraction less than 35% despite optimal medical therapy. Several have studies demonstrated the important role of echocardiography in patient selection for CRT, follow up and estimation of CRT effects, as well as the optimization of biventricular pacemaker. Basically, there are three types of cardiac asynchrony: interventricular asynchrony, between the right and left ventricle, intraventricular asynchrony, between the myocardial segments within the left ventricle and atrioventricular asynchrony, between the atria and ventricles. Although many echocardiographic techniques are used in patient selection for CRT, no ideal approach has yet been found.There are several techniques and parameters used in the assessment of myocardial asynchrony: two dimensional (2D) echocardiography, one dimensional echocardiography (M-mode), Doppler echocardiography, different modalities of tissue Doppler including Colour Coded Tissue Doppler Imaging--TDI, measurements of local tissue deformation indices (strain and strain rate), speckle tracking, 3D echocardiography, semiquantitative assessment of myocardial border, vector velocity imaging. Each of these techniques has advantages and limitations. A special accent in this revue is on the consensus report from the American Society of Echocardiography Dyssynchrony Writing group. According to this consensus report colour coded tissue Doppler is the most appropriate technique for myocardial asynchrony estimation and patients selection for CRT. The same group recommended that definitive decision for CFT implantation should not be based only on echocardiographic analysis, but rather on the whole clinical aspect of the patient.

[Brain natriuretic peptide as a predictor of heart failure in patients with permanent pacemaker].

INTRODUCTION: Brain natriuretic peptide (BNP) has a role in control of cardiovascular and renal functions. OBJECTIVE: The objective was to assess the predictive value of BNP levels for development of heart failure in patients with permanent pacemakers. METHOD: In patients with implanted DDD pacemakers, BNP levels were measured at rest and after exercise testing, on DDD and VVI modes. There were 42 patients (25 males; 59.5%), without symptoms or signs of coronary disease or heart failure, and with normal echocardiograms. According to BNP levels, the patients were divided into three groups: with BNP levels lower than 80 pg/ml, BNP ranging from 81-150 pg/ml, and BNP levels over 151 pg/ml. RESULTS: In the first group (27 patients), BNP levels were significantly higher on VVI compared to DDD mode, both at rest and after exercise (p < 0.01), with all BNP levels within normal range. In the second group (5 pts), BNP levels at rest were also significantly higher on VVI than on DDD mode, p < 0.05. After exercise, these values were also higher on VVI compared to DDD mode, but without statistical significance. The third group (10 pts) as a whole had higher BNP values on VVI compared to DDD mode, with no statistical significance. In patients from this group who later developed heart failure, BNP levels were found to be significantly lower on DDD as opposed to VVI mode at rest, p < 0.05, and even higher significance was found after exercise, p < 0.01. After 6-year follow-up, 2 out of 5 patients from the second group developed dilated cardiomyopathy, and 8/10 patients in the third group experienced heart failure with LV EF 34.1 +/- 10%, LV EDD 6.1 +/- 0.42 cm, LV ESD 4.8 +/- 0.45 cm. Five of these patients died within the follow-up period. CONCLUSION: The increased BNP levels can be valuable for early screening of patients with higher risk of heart failure. In patients with increased BNP at the time of pacemaker implantation, DDD pacing is a modality of choice.

[Echocardiographic evaluation of cardiac resynchronization therapy].

INTRODUCTION: Cardiac resynchronization therapy (CRT) is relatively new tool in treatment of chronic heart failure (HF), especially in dilated cardiomyopathy (DCM) with the left bundle branch block (LBBB). OBJECTIVE: The objective of our study was to assess the success of CRT in treatment of severe HF and the role of echocardiography in the evaluation of results of such therapy. METHOD: The group consisted of 19 patients, 13 males and 6 females, mean age 58.0 +/- 8.22 years (47-65 years) with CRT applied for DCM, severe HF (NYHA III-IV), LBBB and ejection fraction (EF) <35%. The mean follow up was 17 months (6.5-30). Standard color Doppler echocardiography examination was performed in all patients before and after CRT. The parameters of systolic and diastolic left ventricular function, mitral insufficiency and the right ventricular pressure were evaluated. RESULTS: Following the CRT, statistically significant improvement of the end-systolic LV dimension, cardiac output, cardiac index, myocardial performance index (p < 0.01) and stroke index (p < 0.05) was recorded. The mean value of EFLV was increased by 10% and LV fractional shortening improved by 6% in 10/16 (62%) patients. CRT resulted in decreased MR (p < 0.01), prolonged LV diastolic filling time (p < 0.02) and reduced RV pressure (p < 0.05). Interventricular mechanical delay was shortened by 28% (18 msec) CONCLUSION: CRT has an important role in improvement of LV function and correction of ventricular asynchrony. The echocardiography is a useful tool for evaluation of HF treatment with CRT.

Fracture of the subcutaneous patch electrode in a patient with an implanted cardioverter-defibrillator.

There are more than 20 years of experience with implantation of defibrillator devices in humans and the procedure is an important therapeutic option for patients at high risk of life-threatening ventricular arrhythmias. The incidence of new defibrillator implantation has gradually increased, being used even in children, (1) although pediatric use is associated with several complications, especially with epicardial systems,(2) including fracture of the subcutaneous patch,(3-5) mainly because of growth.(3) We present a case of subcutaneous patch electrode fracture in the left axillary pectoral region of a patient who needed the patch for effective defibrillation, and we discuss the methods of treatment.

[Influence of heart failure severity on heart rate variability].

INTRODUCTION: Autonomic regulation of cardiovascular functions in congestive heart failure is characterised by enhanced sympathetic and diminished parasympathetic activity. The long term predominance of sympathetic tone is a significant factor in arrhythmogenesis, sudden cardiac death, and progressive pump failure. Heart rate variability (HRV) is a noninvasive method for estimating the sympatho vagal balance in cardiovascular control. AIM: The aim of this study was to analyse the influence of heart failure severity on HRV. METHOD: HRV was estimated through the spectral analysis of short term ECG (Cardiovit AT 60, Schiller, CH) in 63 patients (78% male, mean age 56.9 +/- 10.9 years) and 14 healthy volunteers (57.1% male, mean age 53.1 +/- 8.2 years). The following spectral components were measured: VLF (very low frequency), LF (low frequency), HF (high frequency), and total power (Tot Power). RESULTS: All spectral componentswere statistically, significantly lower in patients with heart failure in comparison to healthy controls (VLF: 159.89 +/- 147.02 vs. 285.50 +/- 202.77 ms2; p = 0.023, LF: 161.48 +/- 204.01 vs. 474.57 +/- 362.93 ms2; p < 0.001, HF: 88.58 +/- 102.47 vs. 362.71+/- 318.28 ms2; p < 0.001), as well as total power (Tot Power: 723.39 +/- 644.52 vs. 1807.29 +/- 1204.74 ms2; p < 0.001). A significant, negative correlation between HRV parameters and NYHA class was detected in heart failure patients (VLF: r = -0.391; p = 0.002, LF: r = -0.401; p = 0.001, and Tot Power r = -0.372; p = 0.003). Ejection fraction proved to be in significant, positive correlation to VLF (r = 0.541; p = 0.002), LF (r = 0.531; p = 0.003), HF (r = 0.418; p = 0.020), and Tot Power (r = 0.457; p = 0.013). CONCLUSION: Significant HRV reduction is a precursor to incipient heart failure (NYHA I). In heart failure progression, total power as well as the power of all spectral components is progressively reduced. LF and Tot Power are the most prominent parameters for discriminating between the different stages of heart failure. These results could promote HRV as an important decision-making tool in heart failure treatment as well as in monitoring the results of that treatment.

[Implantable "loop recorder"--a new diagnostic tool for syncope of unknown cause].

INTRODUCTION: The implantable loop recorder (ILR) is a new diagnostic tool in cardiology for establishing the causes of unexplained syncope in patients where standard conventional tests, invasive tests included, have failed. The device is a diagnostic "pacemaker," surgically implanted underneath the skin of the chest, with leads attached to the case of the device, not requiring endovenous lead implantation. Heart rhythm is monitored continuously on the basis of an endless loop, up to a maximum period of 14 months. Recording is carried out either by applying an outside activator whenever symptoms occur, or automatically, according to a pre-set algorithm for bradycardia, tachycardia, and/or asystolic detection. OBJECTIVE: The aim of this study was to present this new diagnostic method as well as our first experiences with its implementation. METHOD: We followed 5 patients (3 male, 2 female, mean age: 46.4 +/- 19) who had ILRs ("Reveal Plus," Medtronic Inc., USA) implanted at our centre, over a period of 14 months (7.6 +/- 5.5), concentrating on their clinical course, symptom occurrence, and electronically monitored heart rhythm at the time of ILR auto activation and/or recordings triggered by outside activation whenever a patient's symptoms were discernible. RESULTS: In three patients, the ILR revealed syncope aetiology by documenting heart rhythm at the time of its occurrence. In one patient, involving a lethal outcome, the ILR was not explanted, so that the rhythm at the time of the fatal syncope, although assumed, remained undocumented. In one, most recently implanted patient, follow-up is still in progress. CONCLUSION: The implantable loop recorder represents an important innovation and a step forward in establishing the causes of recurrent syncope, which cannot be determined by standard invasive and non-invasive testing.

[Resynchronisation therapy in patients with heart failure: our results].

INTRODUCTION: Resynchronisation therapy with biventricular permanent pacing stimulation is one method of treating patients with systolic heart failure, with echocardiograph signs of ventricular asynchrony and a prolonged QRS of longer than 120 milliseconds. This method has been accepted in most medical centres around the world and was instigated in our Pacemaker Centre in December 2001, 3 months after FDA approval for human use. OBJECTIVE: The aim of the study was to present this new procedure and the results obtained from our own group of patients. METHOD: A multi-site, biventricular pacemaker, with a special electrode for left-half heart stimulation was implanted in the coronary sinus of 17 patients who had suffered systolic heart failure (12 male and 5 female, average age 59.9 years). For all of them, the duration of the QRS interval was longer than 120 ms, with left bundle branch morphology, and an ejection fraction below 30%. All the patients were NYHA class II or III. Prior to and after the implantation, a 12-channel ECG and ECHO were carried out, a 6-minute hall walk test was performed, additionally, the total walked distance on a flat surface was measured, the general condition of the patient was evaluated, the number of medications being taken was noted, as was the number of days of hospitalisation. RESULTS: The average time from diagnosis to implantation was 22 months, and the average post-operative follow-up was 14 months. Two of the patients died 10 and 7 months after the implantation, due to a new myocardial infarction and refractory heart failure. In addition, one patient did not show any improvement after the implantation of the multi-site pacemaker (there were three "non-responder" patients). All the other patients felt much better: decreased NYHA class for I - II class, increased left ventricle ejection fraction, reduced use of diuretics, increased 6-minute hall walk distance and general walk distance on a flat surface, and decreased number of days of hospitalisation. CONCLUSION: Resynchronisation heart failure therapy in the majority of patients with systolic left ventricular dysfunction and a prolonged QRS interval considerably improves cardiac function, in addition to reducing symptoms and hospital stays.