Diagnostic value of implantable loop recorders in patients with unexplained syncope or palpitations.

BACKGROUND: The implantable loop recorder (ILR) is a small cardiac rhythm-monitoring device. Our aim was to determine ILR diagnostic value in patients with unexplained syncope, presyncope, or palpitations suggesting cardiac arrhythmias. METHODS: This has been a retrospective, observational, single-center study. We included 181 patients in whom ILR was implanted at the Clinical Center of Serbia between January 2006 and July 2019. An event was marked as diagnostic if it led to a diagnosis and ILR was considered diagnostic if it verified or excluded an arrhythmia as the cause of syncope or palpitations. RESULTS: The mean age was 51.8 ± 17.8 years and 94 (51.9%) were male. The mean follow-up period was 20.2 ± 15.8 months. ILR was diagnostic in 98 patients (54.1%). There was no significant difference in diagnostic value of ILR in regard to the baseline patients' characteristics. The mean time to occurrence of the diagnostic event was 11.1 ± 9.6 months. The time to occurrence of a diagnostic event did not differ significantly between patients who underwent basic as compared to extended diagnostics before ILR implantation. CONCLUSIONS: ILR was able to achieve an etiological diagnosis in 54.1% of patients with unexplained syncope, presyncope, or palpitations suggesting cardiac arrhythmias. In a subgroup of patients with recurrent palpitations, ILR was significantly less diagnostic than in patients with syncope or presyncope. ILR should be implanted beforehand in syncope evaluation process.

Permanent endovenous pediatric pacing: absence of lead failure--20 years follow-up study.

BACKGROUND: The aim of the study was to analyze endovenous pacing lead survival in pediatric population implanted by cephalic cut down, or by axillary vein puncture. METHODS: All implantations were performed in total endotracheal anesthesia, by the same surgeon. Implantations of ventricular leads were performed by cephalic vein cut down or by external jugular vein preparation. In dual-chamber pacing, atrial leads were implanted via cephalic vein (along with ventricular lead), by axillary vein puncture or via external jugular vein. All implanted leads were secured by resorbable suture. RESULTS: Over the 20-year follow-up period, 105 children of 5.7 years average age (range 1 day-15 years) were implanted with a permanent endovenous pacing system for congenital or postsurgical complete atrioventricular block or sinus node disease. Within the group, 27 patients (25.7%) weighed less than 10 kg on implantation. A total of 121 endovenous leads were implanted. All ventricular leads were with a passive fixation mechanism, and most of them unipolar (87.6%) and steroid eluting (94.2%). Leads implanted in atrial position were 82% bipolar, predominantly with active fixation (94%), and all steroid eluting. The most frequently used mode of stimulation was VVIR (66.6%). No acute or chronic lead displacement, exit block, sensing problem, lead conductor fracture, insulation defect or infections were observed during the total follow-up of 709 pacing years (average 6.9, range 0-20 years). CONCLUSION: Implantation of the endovenous leads by preparation of the cephalic or puncture of the axillary vein, with lead fixation by resorbable suture represents a method of choice.

[Approach to the Treatment of Atrial Fibrillation in Patients with Cardiovascular Risk Profile: Multicentric International Study].

INTRODUCTION: Atrial fibrillation (AF), the most common arrhythmia that requires treatment, does not come out of the focus of researchers. Monitoring its prevalence and effects of therapy is a good guideline approach to the growing population of patients in which this arrhythmia occurs. OBJECTIVE: The aim of the study was to evaluate the efficacy of treatment of AF and cardiovascular profiles in the observed population. METHODS: In this observational, cross-sectional, multicenter, international study, 584 patients in 30 centers in Serbia and Slovenia, older than 18 years and with AF or in sinus rhythm with a history of AF, were included. The assessment of the efficacy of treatment of AF was performed by analyzing the frequency of adequate therapeutic effect of medication in rhythm or frequency control in patients with AF. RESULTS: The results confirmed that the highest incidence of AF duration is more than seven days, and is accompanied by symptoms. Inadequate frequency regulation was registered at 8.9% of patients. Hypertension was registered in two-thirds of all patients, while other cardiovascular risk factors were registered in about one-third of patients. An echocardiographic finding in the group of patients with AF confirms generally adequate left ventricular function with a slightly enlarged left atrium (4.6±0.8 cm). Increasing age and time from the first episode of AF decreases the probability of maintaining sinus rhythm, while symptomatic AF had a positive impact on the presence of sinus rhythm. Propafenone, sotalol and amiodarone showed a statistically significant connection with a positive therapeutic response, while 3-blockers had a negative impact on the probability of establishing and maintaining sinus rhythm. CONCLUSION: Characteristics of therapeutic approaches, risks, comorbidity of patient populations in Slovenia and Serbia correspond to the fullest extent with the recommendations for good clinical practice, which further stresses the need for extensive measures in these regions.

Crossing the border for health care: access and primary care characteristics for young children of Latino farm workers along the US-Mexico border.

OBJECTIVES: To examine prevalence and correlates of cross-border health care for children of Latino farm workers in counties near the US-Mexico border and to compare access and primary care in the United States and Mexico. METHODS: Two hundred ninety-seven parents at Head Start centers in San Diego and Imperial counties were surveyed regarding percentage of health care received in Mexico and the United States, access, and primary care characteristics. RESULTS: More than half of all health care was reported as received in Mexico. Reasons for Mexican use revolved around cost, accessibility, and perceptions of effectiveness. Parents of insured children reported slightly more US care, yet even this group reported approximately half of health care in Mexico. Insurance status was related to having a regular source of care, while uninsured children reporting most care in Mexico were less likely than uninsured children in the United States to have had a routine health care visit. Primary care characteristics were related to insurance status and source of care. Uninsured children reporting most care in Mexico fared better in some aspects of primary care than uninsured children reporting most care in the United States and as well as children with insurance receiving care in the United States or Mexico. CONCLUSIONS: Children of farm workers living along the US-Mexico border, almost irrespective of insurance status, receive a large proportion of care in Mexico. Especially for uninsured children, parent reports of Mexican care characteristics compare favorably with that received in the United States. Mexican health care might be a buffer against vulnerability to poor health outcomes for these children.

Approach to patients with implanted pacemaker and scheduled surgical or diagnostic procedure.

Application of cardiac electrostimulation in strictly defined indications has been on the increase over the last few decades. Frequent use of this therapy as well as the fact that it is applied predominantly in patients in the seventh decade of life, implies possible signifficant comorbidities and need for various diagnostic and surgical procedures. These are the reasons we decided to point out certain specific features in approaching this patient group in preparation and implementation of these procedures. Preoperative approach starts with usual patient history, with additional information on the type of pacemaker, last pacemaker check and electrocardiogram. This general approach is not substantialy different for pacemaker or ICD patients. What is specific is the possible interferrence caused by devices used in diagnostic or therapeutic procedures (diathermy, lithotripsy). Complications that may arise are usually related to the underlying disease rather than the pacemaker malfunction, but still, careful approach and pacemaker check are warranted, especially in the group marked as "pacemaker dependent". Adequate preoperative assessment, only slightly different from the usual, represents a sufficient guarantee for safe procedures diagnostic, therapeutic or surgical.

[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.

[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.

[The influence of respiratory pattern on heart rate variability analysis in heart failure].

INTRODUCTION: Autonomic dysfunction is present early in the course of heart failure, and has a direct role on deterioration of cardiac function and prognosis. Heart rate variability (HRV) estimates sympathovagal control of heart frequency. The influence of respiratory pattern on HRV is clinically important. Breathing disorders are common in heart failure and highly affect HRV and autonomic evaluation. It was previously shown that slow and deep breathing increased parasympathetic tone, but effects of this respiratory pattern on HRV were not evaluated. OBJECTIVE: The aim of the study was to estimate effects of slow and deep breathing (SDB) on HRV in heart failure patients. METHOD: In 55 patients with heart failure (78% male, mean age 57.18 +/- 10.8 yrs, mean EF = 34.12 +/- 10.01%) and 14 healthy controls (57.1% male, mean age 53.1 +/- 8.2 yrs), short term HRV spectral analysis was performed (Cardiovit AT 60, Schiller). VLF, LF, HF and LF/HF were determined during spontaneous and deep and slow breathing at 0.1 Hz (SDB). RESULTS: LF, HF and LF/HF significantly increased during SDB compared with spontaneous breathing both in controls (LF 50.71 +/- 61.55 vs. 551.14 +/- 698.01 ms2, p < 0.001; HF 31.42 +/- 29.98 vs. 188.78 +/- 142.74 ms2, p < 0.001 and LF/HF 1.46 +/- 0.61 vs. 4.21 +/- 3.23, p = 0.025) and heart failure patients (LF 27.37 +/- 36.04 vs. 94.50 +/- 96.13 ms2, p < 0.001; HF 12.13 +/- 19.75 vs. 41.58 +/- 64.02 ms2, p < 0.001 and LF/HF 3.77 +/- 3.79 vs. 6.38 +/- 5.98, p = 0.031). Increments of LF and HF induced by SDB were significantly lower in patients than healthy controls. Heart failure patients had lower HRV compared to healthy controls both during spontaneous breathing and SDB. During spontaneous breathing, only HF was significantly lower between healthy controls and patients (p = 0.002). During SDB VLF (p = 0.022), LF (p < 0.001) and HF (p < 0.001) were significantly lower in heart failure patients compared to controls. CONCLUSION: These data suggest that SDB increases HRV both in healthy and heart failure patients; the highest increment is in LF range. Differences in spectral profile of HRV between healthy controls and heart failure patients become more profound during SDB. Controlled respiration during HRV analysis might increase sensitivity and reliability in detection of autonomic dysfunction in heart failure patients.

[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.

[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.

Prevalence of venous obstruction in permanent endovenous pacing in newborns and infants: follow-up study.

OBJECTIVE: We examined the prevalence of venous obstruction in 12 newborns and infants with permanent endovenous ventricular pacing, clinically, and by ultrasonographic assessment of hemodynamics (spontaneity, phasicity, velocity, and turbulence of flow) and morphologic parameters (compressibility, wall thickness, and thrombus presence). MATERIAL AND METHODS: All implantations of single ventricular unipolar endovenous steroid leads, were performed via cephalic vein, and pacemakers were placed in subcutaneous pocket in right prepectoral region. After the vascular surgeon has carefully examined all children for presence of venous collaterals in the chest wall, morphologic and hemodynamic parameters of the subclavian, axillary, and internal jugular veins, were assessed by linear-array color Doppler. Lead capacity (LC) was calculated for each patient. RESULTS: Mean age of patients at implant was 6.2 months (range 1 day-12 months), mean weight 6.5 kg (range 2.25-10 kg), and mean height 60.9 cm (range 48-78 cm). Mean LC was 1.99 (range 1.14-3.07). Total follow-up was 1023 and mean follow-up 85.2 pacing months (range 3-156). No clinical signs of venous obstruction were observed. Mild stenosis (20%) of subclavian vein was found by color Doppler in 2/12 patients. Both had adequate lead diameter for body surface. CONCLUSION: Permanent endovenous pacing is a feasible procedure, even in children of body weight less than 10 kg, with quite acceptable impact on venous system patency.

[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.