RESUMEN
OBJECTIVES: Chronic exposure to air pollution caused by particulate matter (PM) with aerodynamic diameters of <10 µm (PM10) and <2.5 µm (PM2.5), dependent on "low emissions" resulting from the combustion of solid fuels in households, significantly increases the risk of cardiovascular events. The aim of the study was to assess the impact of chronic exposure to air pollution in the place of residence on the occurrence of coronary artery disease, hypertension and the presence of electrocardiographic abnormalities in 24-hour Holter ECG recording. MATERIAL AND METHODS: After considering the exclusion criteria, 100 consecutive patients of the cardiology outpatient clinic were enrolled in the study, including 50 patients living for ≥10 years in Warsaw districts with the lowest average concentrations of PM2.5 (group I) and 50 living in the districts with the highest recorded exposure (group II). All patients underwent clinical and physical examination, 12-lead ECG, 2D cardiac echo, and Holter ECG. To avoid the impact of acute exposure, the study was carried out in May - the month with statistically the lowest recorded PM2.5 concentrations. RESULTS: In the group of patients exposed to higher concentrations of PM2.5 in the place of residence, coronary artery disease and arterial hypertension were significantly more frequent, while in the Holter ECG examination, ventricular arrhythmias, conduction disturbances and ST-segment and T-wave changes were independently associated with exposure to air pollution. CONCLUSIONS: Chronic exposure to air pollution in the place of residence contributes to the occurrence of chronic coronary syndrome and hypertension. Chronic exposure to air pollution seems to be a significant factor increasing the incidence of ventricular arrhythmia, conduction disturbances and ST-segment depression episodes in Holter monitoring. Int J Occup Med Environ Health. 2022;35(3):353-60.
Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire , Enfermedad de la Arteria Coronaria , Hipertensión , Contaminantes Atmosféricos/efectos adversos , Contaminantes Atmosféricos/análisis , Contaminación del Aire/efectos adversos , Contaminación del Aire/análisis , Enfermedad de la Arteria Coronaria/epidemiología , Electrocardiografía , Exposición a Riesgos Ambientales/efectos adversos , Exposición a Riesgos Ambientales/análisis , Humanos , Hipertensión/epidemiología , Material Particulado/efectos adversos , Material Particulado/análisisRESUMEN
Clinically silent cardiac disease is frequently observed in rheumatoid arthritis (RA), and cardiovascular complications are the leading cause of mortality in RA. We sought to evaluate the myocardium of young RA patients without known cardiac disease using cardiac magnetic resonance (CMR), including T1/T2 mapping sequences. Eighteen RA patients (median age 41 years, 83% females) mainly with low disease activity or in remission and without any known cardiovascular disease were prospectively included to undergo CMR. A control group consisted of 10 sex- and age-matched patients without RA or any known structural cardiovascular disease. Heart chambers size and left/right ventricular systolic function were similar in patients with RA and controls. Signs of myocardial oedema were present in up to 39% of RA patients, including T2 time above cut-off value in 7 patients (39%) in comparison to none of the controls (p = 0.003) and T2 signal intensity ratio above the cut-off value in 6 patients (33%) and in none of the controls (p = 0.06). Extracellular volume was similar in both groups signifying a lack of diffuse fibrosis in studied group of RA patients. There were also no signs of late gadolinium enhancement (LGE) in either group except for one patient with RA who was found to have prior silent myocardial infarction. No correlation was found between markers of disease severity and markers of oedema observed on CMR in patients with RA. Nevertheless, patients with increased T2 time (≥50 ms) were more likely to have X-ray erosions (p = 0.02) and a longer duration between symptom onset and diagnosis (p = 0.02). Finally, there were no significant arrhythmias on 24-h ECG Holter monitoring in RA patients. CMR features of myocardial oedema without signs of myocardial fibrosis were found in 39% of young RA patients without known heart disease or cardiac symptoms. Presence of myocardial oedema was associated with X-ray erosions and a longer duration between symptom onset and diagnosis. The clinical significance of the observed early myocardial changes accompanying RA requires additional studies.
RESUMEN
INTRODUCTION: It has been claimed that patients with systemic sclerosis (SSc) have an increased risk of developing cardiac arrhythmias and atrioventricular conduction disorders, but it is unknown whether SSc may be a cause of sinoatrial conduction abnormalities. AIM: To establish the incidence of sinoatrial conduction abnormalities in patients with SSc and verify the relationship of these disorders with various clinical descriptors of SSc. MATERIAL AND METHODS: Forty women with systemic sclerosis of varying duration and severity underwent 24-hour ambulatory ECG monitoring. The occurrence of type I second-degree sinoatrial block (SA-block) and calculation of sinoatrial conduction time (SACT) were evaluated to establish the incidence of sinoatrial conduction abnormalities. The measurements of SACT were obtained using spontaneous atrial premature beats. The effect of various clinical descriptors on sinoatrial conduction abnormalities was assessed. RESULTS: The mean ± SD SACT for the 40 patients was 150 ±15 ms. Prolonged (> 150 ms) SACT was found in 20 patients. In 14 (35%) patients SA-block occurred during ambulatory ECG monitoring. The discriminant analysis identified the severity of SSc cutaneous manifestation as an independent marker for developing SA-block (p < 0.005) and SACT prolongation (p < 0.0002). CONCLUSIONS: Patients with SSc are at an increased risk of developing type I second-degree sinoatrial block and prolonged sinoatrial conduction time. The occurrence of these abnormalities is related to the severity of skin involvement. Therefore, cardiological diagnosis using 24-hour ambulatory ECG in this group of patients should be focused also on this type of disorders. Prospective, controlled studies are needed to assess their prognostic role.
RESUMEN
INTRODUCTION: It is known that the administration of the drug during the oral aspirin challenge (OAC) can cause hypersensitivity symptoms not only from the respiratory system or skin, but also from the cardiovascular system. AIM: To assess the occurrence and nature of cardiovascular adverse events during the OAC in patients suspected of hypersensitivity to nonsteroidal anti-inflammatory drugs (NSAIDs). MATERIAL AND METHODS: The study included 52 patients with symptoms of hypersensitivity to aspirin (ASA) or other NSAIDs in the form of skin reactions or respiratory response in anamnesis. Patients were treated with OAC and simultaneously were subject to monitoring of clinical manifestations of hypersensitivity to ASA/NSAIDs, ventilation disorders and cardiovascular functions. RESULTS: The most common reaction of the cardiovascular system during OAC was tachycardia or supraventricular and ventricular extrasystoles, regardless of the day of the study and the result of OAC. Supraventricular and ventricular tachycardia was recorded incidentally. Atrial or ventricular fibrillation or flutter was not observed. There was no evidence of any ischemic heart disease. In 2 patients, hypotension was registered, but only 1 of them required typical treatment of anaphylaxis. CONCLUSIONS: No clinically significant cardiac arrhythmias were recorded during OAC. The changes observed in the records of blood pressure and ECG monitoring show that OAC performed in accordance with the current guidelines does not pose a high risk to the patient's health and life as a result of cardiovascular reactions.
RESUMEN
INTRODUCTION: Ion channel gene mutations are risk factors for SCD. THE AIM: To assess the prognostic value of A2753831C, C2505734T, C2505846A, G2753881A, T2755854C and T2755875G mutations in the KCNQ1 gene in patients after MI. MATERIAL AND METHODS: The study group of 100 patients after MI was divided into two groups: patients with mutations (n=23) and patients without mutations (n=77). The subjects underwent physical examinations, laboratory tests, ECG, Holter ECG and echocardiography. The examinations were repeated every 12 months. Cardiac events including deaths occurred during the observation period. RESULTS: The mean observation time was 8 ± 4,3 years. KCNQ1 gene mutations were found in 23 subjects and were four times more frequent in men than in women. Parameters such as QRS ≥ 110 ms, QTc ≥ 440 ms, VEBs ≥ 100 per 24 hours, nsVT and LVEF ≤40% showed statistically significant differences between the group of patients who died and the group of patients who survived. LVEF ≤ 40% and VEBs ≥ 100/24 h were the factors that correlated the most with deaths. KCNQ1 gene mutations, PQ interval ≥ 200ms and QTd ≥ 60ms had no impact on death. CONCLUSIONS: The occurrence of KCNQ1 gene mutations in patients after MI is higher in men than in women. The presence of KCNQ1 gene mutations is not an additional risk factor for increased mortality in patients after MI. LVEF ≤40% and VES ≥100/24 h have a significant prognostic value in predicting deaths in patients after MI.
Asunto(s)
Muerte Súbita Cardíaca/etiología , Canal de Potasio KCNQ1/genética , Infarto del Miocardio/genética , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Mutación , Pronóstico , Factores de Riesgo , Volumen Sistólico , Tasa de SupervivenciaRESUMEN
BACKGROUND: In animals, hemodynamic conditions during left ventricular (LV) end-diastole are crucial for the excitation of autonomic afferents distributed throughout cardiac chambers and large thoracic vessels. The objective of the study was to select the echocardiographic indices of LV diastolic function that are the most potent predictors of the heart's spontaneous baroreflex in humans. METHODS: In 47 untreated hypertensive patients (26 with normal and 21 with increased left atrium diameter) and 24 healthy controls, baroreflex sensitivity (BRS) was assessed in the low (αLF; 0.04-0.15 Hz) and high frequency (αHF; 0.15-0.4 Hz) components in the supine and during tilting. The [Formula: see text] normalized to LV end-diastolic diameter (the [Formula: see text] index) is a marker of the septum late diastolic distension rate ([Formula: see text] denotes peak late diastolic velocity at the septal mitral annulus) under the corresponding transmitral pressure gradient that determines the peak velocity of blood flow (A) into the LV chamber. RESULTS: The [Formula: see text] markedly stronger than [Formula: see text] ratio correlated with the BRS. In the best-fit models of multivariable linear regression, the [Formula: see text] index was the independent predictor of the αLF BRS at tilting (ß = -0.3; p = 0.01). Independent of clinical and echocardiographic parameters, the [Formula: see text] index predicted also both the αHF BRS in the supine position (ß = -0.23; p = 0.01) and the αHF BRS reinforcement due to increased preload (ß = -0.28; p = 0.001). CONCLUSIONS: The [Formula: see text] index is a reliable marker of diastolic dysfunction that evokes significant heart's baroreflex impairment and is markedly stronger than [Formula: see text] ratio associated with these systemic consequences of altered LV diastole hemodynamics.
Asunto(s)
Barorreflejo/fisiología , Hemodinámica/fisiología , Hipertensión/prevención & control , Función Ventricular Izquierda/fisiología , Adulto , Diástole/fisiología , Ecocardiografía , Femenino , Inclinación de Cabeza , Atrios Cardíacos/fisiopatología , Ventrículos Cardíacos/fisiopatología , Humanos , Hipertensión/fisiopatología , Masculino , Persona de Mediana Edad , Válvula Mitral/fisiología , Posición Supina , Disfunción Ventricular Izquierda/fisiopatologíaRESUMEN
BACKGROUND: The reliability of noninvasive Holter method for the calculation of sinoatrial conduction time (SACT) has not been confirmed by results of invasive electrophysiological studies of sinus nodal function. The aim of this study was to compare the values of SACT obtained by Holter method with values estimated by premature atrial stimulation method. METHODS: The study population consisted of 61 patients, in whom the 24-hour ambulatory ECG monitoring had shown the occurrence of atrial premature beats. All these subjects were undergoing electrophysiological study including programmed atrial and ventricular stimulation. The measurements of SACT were obtained using spontaneous atrial premature beats (Holter method) and high right atrial stimulation (Strauss method). RESULTS: There was a good correlation between measurements of SACT by Holter method and Strauss method (r = 0.79; P < 0.001). There was no significant difference between values of SACT estimated by two compared methods. However, in certain patients, there were appreciable differences and SACT measured using spontaneous premature beats was shorter in 34 and longer in 23 patients than that estimated by the Strauss method. The values of SACT calculated by Holter method and Strauss method were significantly (P < 0.001) higher in patients with sick sinus syndrome than in those without evidence of sinus node dysfunction. CONCLUSIONS: Good correlation between values of SACT obtained by two compared methods suggests that single measurement performed using Holter method may be adequate for reliable calculation of SACT.
Asunto(s)
Electrocardiografía Ambulatoria , Síndrome del Seno Enfermo/diagnóstico , Síndrome del Seno Enfermo/fisiopatología , Nodo Sinoatrial/fisiopatología , Femenino , Frecuencia Cardíaca , Humanos , Masculino , Persona de Mediana Edad , Reproducibilidad de los ResultadosRESUMEN
AIMS: To determine the clinical significance of the sinoatrial block II° of the Wenckebach type (block W) identified during Holter monitoring. METHODS AND RESULTS: The study included 300 patients (mean age 54 ± 17 years; 130 women) with symptoms suggestive of arrhythmia who underwent Holter monitoring. Block W was identified by a dedicated computer program and subsequently confirmed by a cardiologist. Block W was diagnosed in 88 patients (29%). It occurred only during sleep in 37 (12%) patients and during both daytime activity and sleep in 51 (17%) patients. Block W only during sleep happened predominately in young patients aged between 20 and 30 years, whereas episodes that occurred during both daytime and sleep were found mainly in patients between 60 and 70 years of age. Prospective observation time averaged 41 ± 11 months, and the time to the diagnosis of sinus node disease was 26 ± 10 months. Cox multivariate analyses showed that block W during both daytime and sleep is an independent predictor for the future diagnosis of sinus node disease [hazard ratio-13.6 (5.2-35.5); P < 0.0001]. Age-specific analyses confined this effect to the patients ≥50 years of age. The results also suggest that in patients ≥50 years of age block W during both daytime and sleep may be related to a significant improvement in survival [hazard ratio-0.03 (0.007-0.16); P < 0.0001]. CONCLUSION: Block W during daytime activity in patients with symptoms suggestive of arrhythmia indicates an increased likelihood of the future diagnosis of sinus node disease.
Asunto(s)
Electrocardiografía Ambulatoria/estadística & datos numéricos , Bloqueo Sinoatrial/diagnóstico , Bloqueo Sinoatrial/mortalidad , Síncope/diagnóstico , Síncope/mortalidad , Adolescente , Adulto , Distribución por Edad , Anciano , Anciano de 80 o más Años , Causalidad , Comorbilidad , Electrocardiografía Ambulatoria/métodos , Femenino , Humanos , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Polonia/epidemiología , Prevalencia , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Distribución por Sexo , Bloqueo Sinoatrial/clasificación , Tasa de Supervivencia , Evaluación de Síntomas/métodos , Evaluación de Síntomas/estadística & datos numéricos , Síncope/clasificación , Adulto JovenRESUMEN
A 57 year-old man treated with amitriptyline was admitted because of several episodes of syncope. In ECG, the incomplete left bundle branch block was masked by the complete right bundle branch block and left anterior fascicular block.
Asunto(s)
Amitriptilina/efectos adversos , Antidepresivos Tricíclicos/efectos adversos , Bloqueo de Rama/inducido químicamente , Síncope/inducido químicamente , Bloqueo de Rama/diagnóstico , Electrocardiografía , Humanos , Masculino , Persona de Mediana Edad , Síncope/diagnósticoRESUMEN
BACKGROUND: To evaluate the usefulness of the Holter method of sinoatrial conduction time (SACT) calculation in predicting the future occurrence of sinus node disease, and the emergence of indications for permanent pacing in patients with unexplained syncope. METHODS: The study group included 218 patients (mean age 55 ± 17 years, 116 men) with syncope of unknown etiology in whom spontaneous atrial premature depolarizations (APDs) occurred during Holter monitoring and SACT could be calculated. A SACT value during daily activity > 150 ms was assumed as abnormal. RESULTS: The prospective observation time was 48 ± 11 months. During follow-up sinus node disease was diagnosed in 22 persons, including 18 patients with baseline SACT > 150 ms and 4 with SACT < 150 ms. Indications for pacemaker implantation were found in 16 patients, including 13 patients with baseline SACT > 150 ms and 3 with SACT < 150 ms. In subjects with and without sinus node disease diagnosed during the observation period, baseline SACTvalues were 175 ± 52 ms and 87 ± 34 ms, respectively (p < 0.01), and in patients qualified and not qualified for permanent pacing, the respective values were 178 ± 59 ms and 81 ± 38 ms(p < 0.01). Multivariate Cox analysis showed a significant relationship between baseline SACT > 150 ms and a future diagnosis of sinus node disease and pacemaker implantation. CONCLUSIONS: The results suggest that the Holter method of SACT calculation is useful in predicting sinus node disease and indications for permanent pacing in patients with unexplained syncope.
Asunto(s)
Electrocardiografía Ambulatoria , Síndrome del Seno Enfermo/diagnóstico , Nodo Sinoatrial/fisiopatología , Potenciales de Acción , Adulto , Anciano , Anciano de 80 o más Años , Estimulación Cardíaca Artificial , Distribución de Chi-Cuadrado , Femenino , Humanos , Masculino , Persona de Mediana Edad , Análisis Multivariante , Valor Predictivo de las Pruebas , Pronóstico , Modelos de Riesgos Proporcionales , Estudios Prospectivos , Síndrome del Seno Enfermo/fisiopatología , Síndrome del Seno Enfermo/terapia , Síncope/diagnóstico , Síncope/fisiopatología , Factores de Tiempo , Adulto JovenRESUMEN
BACKGROUND: The present study of patients with Wenckebach-type second-degree sinoatrial block (W-block) evaluated the probability of the development of a more advanced grade of sinoatrial block. Data on the clinical significance of W--block are limited. It is unknown whether W-block predicts a more advanced grade of sinoatrial block. METHODS: Standard ECGs of 412 patients with symptoms that might have been related to cardiac arrhythmias were reviewed for the presence of W-block. In the initial ECG W-block occurred in 29. During the follow-up period of 62 +/- 35 months the main end-point was the first episode of type II second-degree sinoatrial block. An additional end-point was the occurrence of a sinus pause greater than 3 s or the development of type II second-degree sinoatrial block. RESULTS: Of the 29 patients with W-block initially, 6 (20.7%) developed higher grade sinoatrial block, and sinoatrial arrhythmic events occurred in 9 (31%). In the 383 patients without W-block subsequent episodes of higher grade sinoatrial block occurred in 14 (3.7%) and sinoatrial arrhythmic events in 28 (7.3%). A multivariate Cox analysis identified W-block as an independent marker for developing type II second-degree sinoatrial block (HR = 3.72, 95% CI 1.39-9.99) and for the occurrence of sinoatrial arrhythmic events (HR 3.01, 95% CI 1.37-6.58). CONCLUSIONS: In patients with symptoms that might be caused by cardiac arrhythmias the presence of W-block in a standard ECG indicates a high probability of developing a more advanced grade of sinoatrial block. (Cardiol J 2007; 14: 391-395).
RESUMEN
BACKGROUND: The use of tilt testing (TT) in guiding therapy in patients with syncope remains controversial. AIM: To assess the long-term effectiveness of TT-based therapy in patients with syncope of unknown origin. METHODS: The study group consisted of 340 patients (182 females, mean age 38.2+/-16.5 years, range 15-78 years) with at least two syncopal episodes during 6 months preceding the study. TT was performed at 60 degrees angle for 20 min, followed by sublingual nitroglycerine (NTG) challenge (250 microg) when necessary. After positive baseline TT and returning to supine position, 0.1 mg/kg of propranolol was intravenously administered and a second TT was performed. All patients with positive TT were advised to take propranolol, midodrine or fludrocortisone for 6 months -- the choice of agent was based on standard criteria. The time to first syncope was an indicator of the efficacy of treatment and a recurrence of syncope was the end-point of the study. In patients who did not faint during follow-up, the last date of contact was taken as the end of observation period. RESULTS: Out of 340 patients who underwent TT, 148 with positive TT and propranolol challenge were included in the study; 82 patients (group I) received long-term therapy whereas 66 did not (group II). During a 12.8+/-0.9 month follow-up, syncope recurred in 86 patients - 40 (49%) from group I and 46 (70%) from group II (p<0.01). Survival analysis showed that medical therapy was associated with a significant reduction of the risk of syncope recurrence (RRR: 36%, 95% CI: 23-47). The greatest benefit from long-term treatment was documented in patients taking propranolol (RRR: 42%; 95% CI: 18-58; p<0.008), particularly in those in whom intravenous propranolol prevented TT-induced syncope (RRR: 50%; 95% CI: 23-67; p<0.012). Risk reduction in patients treated with midodrine or fludrocortisone was moderate (RRR: 22%; 95% CI: 11-34; p>0.09). CONCLUSIONS: Carefully selected and TT-based long-term pharmacological treatment is associated with a 36% risk reduction of syncope recurrences in patients with syncope of unknown origin.
Asunto(s)
Síncope/tratamiento farmacológico , Pruebas de Mesa Inclinada , Adolescente , Antagonistas Adrenérgicos alfa/uso terapéutico , Antagonistas Adrenérgicos beta/uso terapéutico , Adulto , Anciano , Femenino , Fludrocortisona/uso terapéutico , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Midodrina/uso terapéutico , Nitroglicerina , Propranolol/uso terapéutico , Recurrencia , Pruebas de Mesa Inclinada/métodos , Factores de Tiempo , Resultado del Tratamiento , VasodilatadoresRESUMEN
UNLABELLED: To date, the clinical significance of fused T and U waves, termed as TU complexes, has not been evaluated. The aim of the study was to present the clinical characteristics of the patients with TU complexes and to assess the value of this ECG abnormality in risk stratification after myocardial infarction. In the group of 330 postinfarction patients (mean age 61 +/- 10 years, 279 men and 51 women), 50 (15%) had TU complexes in one or more leads of a standard ECG. In patients with TU complexes, the decreased left ventricular ejection fraction, frequent (> or = 10/hour) ventricular premature beats and non-sustained ventricular tachycardia detected on 24-hours ECG monitoring, increased QT dispersion, ST-segment depression and ST-segment elevation on a routine ECG were more common than in patients without TU complexes. During a follow-up period of 43 +/- 17 months, 88 patients died from all causes. At univariate Cox analysis the presence of TU complexes (hazard ratio 3.30; 95% confidence interval 2.09-5.21) and left ventricular ejection fraction < 40% (hazard ratio 3.82; 95% confidence interval 2.51-5.82) were the best predictors of mortality among the 9 evaluated clinical and electrocardiographic variables. The multivariate, stepwise Cox analysis selected ejection fraction < 40% (hazard ratio 3.09; 95% confidence interval 2.00-4.80), TU complexes (hazard ratio 2.28; 95% confidence interval 1.42-3.69), RR interval < 800 ms (hazard ratio 1.62; 95% confidence interval 1.06-2.47), and age of patients > 65 years (hazard ratio 1.58; 95% confidence interval 1.03-2.42) as an independent predictors of all cause mortality. CONCLUSION: The presence of TU complexes on a routine ECG is associated with impaired left ventricular function, increased predisposition to ventricular arrhythmias and higher risk of mortality. TU complexes may be considered as a new electrocardiographic marker of poor prognosis in patients after myocardial infarction.
Asunto(s)
Electrocardiografía , Sistema de Conducción Cardíaco/fisiopatología , Infarto del Miocardio/fisiopatología , Disfunción Ventricular Izquierda , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Infarto del Miocardio/complicaciones , Infarto del Miocardio/mortalidad , Valor Predictivo de las Pruebas , Pronóstico , Factores de Riesgo , Sensibilidad y Especificidad , Análisis de Supervivencia , Factores de Tiempo , Disfunción Ventricular Izquierda/fisiopatologíaRESUMEN
BACKGROUND: Patients with essential hypertension (EH) and left ventricular hypertrophy (LVH) have an increased risk of cardio-vascular complications. Alterations in the autonomic nervous system (ANS) activity may play a role in the development of serious cardiac arrhythmias and mortality in these patients. AIM: To examine the activity of ANS in patients with established EH in relation to the presence of LVH. METHODS: The study group consisted of 70 subjects: 50 patients with untreated EH (mean age 44.4+/-12.7 years, 28 patients without LVH and 22 with LVH), and 20 age-matched healthy volunteers. ANS reactivity was assessed using heart rate variability (HRV) analysed during tilt table testing at 60 degrees. The following 5-min time-periods were analysed: (A) before tilting (supine position), (B) initial period of tilting, (C) last 5 min of tilting, and (D) immediately after completion of tilt test (after return to supine position). RESULTS: Patients with EH without LVH had a higher increase of LF/HF values (period B versus period C) compared with controls (p<0.05). The change from tilt to supine position caused significantly lower change in lnHF values in patients with EH and LVH than in controls (p<0.01) or patients with EH without LVH (p<0.005). In patients with EH and LVH a significant correlation between HF and LVmass/height (r=-0.5, p<0.01) was noted. Compared with healthy controls, patients with EH and LVH had significantly lower HRV parameters [lnLF values were significantly lower in all analysed periods, (p<0.05), and lnHF - during period D, (p<0.01)] whereas LF/HF ratio assessed during period D was significantly higher (p<0.05). CONCLUSIONS: In patients with EH without LVH a relative dominance of sympathetic activity is present. LVH in EH leads to a decrease in vagal drive and progressive inhibition of parasympathetic activity, both of which decrease HRV. These changes may play an important role in the electrical instability of hypertrophied myocardium.
RESUMEN
BACKGROUND: Analysis of pathophysiological mechanisms responsible for vaso-vagal reaction reveals a close relationship between neurocardiogenic syncope and the preceding abnormalities of autonomic nervous system (ANS). Therefore, the interest in the assessment of heart rate variability (HRV) for detecting and establishing therapy in patients with syncope due to vaso-vagal mechanism is not surprising. AIM: To assess ANS changes during tilt testing in patients with syncope of unknown origin. METHODS: Forty patients (18 males, mean age 34.8+/-15.8 years) with a history of at least two syncopal episodes during the last 6 months and 24 healthy controls underwent tilt testing. Spectral HRV analysis was performed from ECG recorded 5 min before tilting (period A), 5 min after tilting (period B), and 5 min before syncope (or 20-25 min of tilt test when syncope did not occur) (period C). RESULTS: Tilt test was positive in 23 (58%) patients; 12 (30%) had mixed response, 10 (25%) - vasodepressive, and 1 (3%) - cardioinhibitory reaction. The mean time from tilt to syncope was 22.3 minutes. One (4%) control subject developed syncope. In all groups a decrease of LF and HF power, as well as an increase in the LF/HF ratio in response to tilting were observed. The LF/HF values were significantly different between patients with mixed vaso-vagal reaction and controls (1.9 vs 4.2; p=0.04). In the C-B periods the highest decrease in the HF spectra was found in patients with mixed reaction and was significantly greater than in other patients or controls. Also, patients with mixed reaction had the highest increase in LF values which was significantly more pronounced than in patients with vasodepressive reaction (10139.3 vs 466.9; p=0.003). As a result, the change in LF/HF ratio was positive in patients with mixed reaction, controls and patients with negative result of tilt test, and negative - in patients with vaso-depressive syncope, reaching statistical significance between patients with mixed and vaso-depressive response (2.04 vs -0.51; p=0.03). CONCLUSIONS: The pattern of HRV changes during tilt testing depends on the type of vaso-vagal reaction which leads to syncope. The most accurate HRV parameter for identification of patients with reflex syncope is the LF/HF ratio.