Nogueira da Silva - Academia.edu (original) (raw)

Papers by Nogueira da Silva

Research paper thumbnail of P1461Risk of atrial fibrillation after catheter ablation of typical atrial flutter: a long-term outcome study

EP Europace, 2017

The apnea-hypopnea index decreased significantly after RFCA (baseline 28.7613.9, after RFCA 20.76... more The apnea-hypopnea index decreased significantly after RFCA (baseline 28.7613.9, after RFCA 20.7613.2, P<0.001) in OSA group. The prevalence of recurrence of AF at 1-year follow-up was equivalent between the two groups (OSA group: 20%, no OSA group: 21%). Conclusions: RFCA for paroxysmal AF decreased the apnea-hypopnea index. Neural ablation may contribute to improve sleep-disordered breathing and RFCA success rate in patients with OSA.

Research paper thumbnail of Alterations in autonomic response during head-up tilt testing in paroxysmal atrial fibrillation patients: A wavelet analysis

Revista portuguesa de cardiologia: orgao oficial da Sociedade Portuguesa de Cardiologia = Portuguese journal of cardiology: an official journal of the Portuguese Society of Cardiology

ABSTRACT

Research paper thumbnail of R on T phenomenon

Revista portuguesa de cardiologia : orgão oficial da Sociedade Portuguesa de Cardiologia = Portuguese journal of cardiology : an official journal of the Portuguese Society of Cardiology

Research paper thumbnail of Remote monitoring for follow-up of patients with implantable cardiac devices

Revista Portuguesa de Cardiologia (English Edition), 2013

With a widening of indications for cardiac devices, especially in view of the clinical benefits o... more With a widening of indications for cardiac devices, especially in view of the clinical benefits of implantable cardioverter-defibrillators and cardiac resynchronization therapy, the number of patients with such devices is growing steadily. However, the resources required, and the need for long-term regular interrogation in dedicated clinics, represent a significant burden for already overstretched electrophysiology teams and hospital services. Remote telemonitoring is increasingly used for such follow-up, as it is a safe and effective alternative to conventional follow-up programs in outpatient clinics. This technology has been shown to be technically reliable, enabling early identification of device malfunction, arrhythmic events and heart failure decompensation, while reducing the risk of under-reporting, the number of outpatient clinic visits and hospitalizations due to cardiac events, and healthcare costs. Further studies are needed to determine how best to implement this new technology in a cost-effective manner, and what new legislation governing the use of remote monitoring in clinical practice may be required. In this article, we describe current systems, review the technical and clinical evidence in the literature regarding remote monitoring of implantable cardiac devices, and expand on outstanding questions.

Research paper thumbnail of Impacto da terapia de ressincronização cardíaca na qualidade de vida em doentes com insuficiência cardíaca congestiva refractária

Research paper thumbnail of Influência do género na qualidade de vida em doentes com insuficiência cardíaca

Research paper thumbnail of Inducibility of atrial fibrillation during electrophysiologic evaluation is associated with increased dispersion of atrial refractoriness

International Journal of Cardiology, 2009

The impact of atrial dispersion of refractoriness (Disp_A) in the inducibility and maintenance of... more The impact of atrial dispersion of refractoriness (Disp_A) in the inducibility and maintenance of atrial fibrillation (AF) has not been fully resolved. Aim: To study the Disp_A and the vulnerability (A_Vuln) for the induction of self-limited (b 60 s) and sustained episodes of AF. Methods and results: Forty-seven patients with paroxysmal AF (PAF): 29 patients without structural heart disease and 18 with hypertensive heart disease. Atrial effective refractory period (ERP) was assessed at five sites-right atrial appendage and low lateral right atrium, high interatrial septum, proximal and distal coronary sinus. We compared three groups: group A-AF not inducible (n = 13); group B-AF inducible, self-limited (n = 18); group C-AF inducible, sustained (n = 16). Age, lone AF, hypertension, left atrial and left ventricular (LV) dimensions, LV systolic function, duration of AF history, atrial flutter/tachycardia, previous antiarrhythmics, and Disp_A were analysed with logistic regression to determine association with A_Vuln for AF inducibility. The ERP at different sites showed no differences among the groups. Group A had a lower Disp_A compared to group B (47 ± 20 ms vs 82 ± 65 ms; p = 0.002), and when compared to group C (47 ± 20 ms vs 80 ± 55 ms; p = 0.008). There was no significant difference in Disp_A between groups B and C. By means of multivariate regression analysis, the only predictor of A_Vuln was Disp_A (p = 0.04). Conclusion: In patients with PAF, increased Disp_A represents an electrophysiological marker of A_Vuln. Inducibility of both self-limited and sustained episodes of AF is associated with similar values of Disp_A. These findings suggest that the maintenance of AF is influenced by additional factors.

Research paper thumbnail of False positive responses to head-up tilt testing in elderly patients with paroxysmal atrial fibrillation

Revista portuguesa de cardiologia : orgão oficial da Sociedade Portuguesa de Cardiologia = Portuguese journal of cardiology : an official journal of the Portuguese Society of Cardiology, 2008

The autonomic nervous system (ANS) plays a role as a modulator in the pathogenesis of paroxysmal ... more The autonomic nervous system (ANS) plays a role as a modulator in the pathogenesis of paroxysmal atrial fibrillation (PAF). The clinical pattern of vagally mediated PAF has been observed mainly in young patients. Neurocardiogenic responses during orthostatic stress are related to autonomic reflexes in which the vagal influence predominates. To evaluate the susceptibility of elderly patients with PAF to activation of vasovagal syncope mechanisms. We performed passive head-up tilt testing (HUT) in 34 patients (62% women, aged 72 +/- 7 years), with > or = 1 year of clinical history of PAF--19 without structural heart disease, 11 with hypertensive heart disease and 4 with coronary artery disease (who had no previous myocardial infarction, had undergone myocardial revascularization, and had no documented ischemia) (PAF group), and compared the results with those obtained in a group of 34 age-matched patients (53% women, aged 74 +/- 6 years), who underwent HUT due to recurrent syncope ...

Research paper thumbnail of Sequências Short-Long-Short Como Indutores de Taquicardia Ventricular

Revista Portuguesa De Cardiologia, Jan 12, 2011

Research paper thumbnail of Alterations in autonomic response during head-up tilt testing in paroxysmal atrial fibrillation patients: A wavelet analysis

Revista portuguesa de cardiologia: orgao oficial da Sociedade Portuguesa de Cardiologia = Portuguese journal of cardiology: an official journal of the Portuguese Society of Cardiology

ABSTRACT

Research paper thumbnail of Hemodynamic device-based optimization in cardiac resynchronization therapy: concordance with systematic echocardiographic assessment of AV and VV intervals

Research Reports in Clinical Cardiology, 2015

Research paper thumbnail of Short QT syndrome presenting as syncope: How short is too short?

Revista Portuguesa de Cardiologia (English Edition), 2014

We report the case of a 52-year-old man who presented to our emergency department (ED) after thre... more We report the case of a 52-year-old man who presented to our emergency department (ED) after three episodes of syncope in the seven hours before admission. During his stay in the ED he had recurrent ventricular tachycardia (VT) requiring external electrical cardioversion. A 12-lead electrocardiogram (ECG) showed a short QT (SQT) interval (270 ms, QTc 327 ms), with frequent R-on-T extrasystoles triggering sustained polymorphic VT. After exclusion of other precipitating causes, the patient was diagnosed as having SQT syndrome (SQTS) according to the Gollob criteria. To our knowledge, this is the first known documentation of an SQT-caused arrhythmic episode on a 12-lead ECG, as well as the first reported case of SQTS in Portugal. The patient received an implantable cardioverter-defibrillator and was discharged. At a follow-up assessment 14 months later he was symptom-free, interrogation of the device showed no arrhythmic events, and the ECG showed a QT interval of 320 ms (QTc 347 ms).

Research paper thumbnail of Assessment of T-wave alternans after acute myocardial infarction: influence of the timing of PTCA on cardiac electrical stabilization

Revista portuguesa de cardiologia : orgão oficial da Sociedade Portuguesa de Cardiologia = Portuguese journal of cardiology : an official journal of the Portuguese Society of Cardiology, 2006

It is accepted that the timing of myocardial revascularization in patients undergoing PTCA for th... more It is accepted that the timing of myocardial revascularization in patients undergoing PTCA for the treatment of acute myocardial infarction (AMI) may improve the clinical outcome. However, its impact on microvolt T-wave alternans (TWA), a recognized tool for assessing vulnerability to ventricular tachyarrhythmias that can cause sudden cardiac death in infarction survivors, remains unknown. To analyze TWA in patients with AMI treated by PTCA and assess whether the timing of myocardial revascularization can influence TWA measurements. We studied 79 patients (67 male; 57 +/- 11 years) who underwent successful PTCA for the treatment of AMI. The presence of TWA was assessed using a HearTwave system (Cambridge Heart, Inc.) within 30 days of AMI. Orthogonal Frank XYZ leads and associated vector magnitude (microvolt alternans sensors) and 7 standard ECG leads were recorded during a treadmill manual exercise protocol to increase heart rate slowly to approximately 110 bpm. TWA was considered ...

Research paper thumbnail of Acesso femoral venoso: uma alternativa excecional para a implantação de pacemaker definitivo

Revista Portuguesa de Cardiologia, 2014

The classic transvenous implantation of a permanent pacemaker in a pectoral location may be precl... more The classic transvenous implantation of a permanent pacemaker in a pectoral location may be precluded by obstruction of venous access through the superior vena cava or recent infection at the implant site. When these barriers to the procedure are bilateral and there are also contraindications or technical difficulties to performing a thoracotomy for an epicardial approach, the femoral vein, although rarely used, can be a viable alternative. We describe the case of a patient with occlusion of both subclavian veins and a high risk for mini-thoracotomy or videothoracoscopy, who underwent implantation of a permanent single-chamber pacemaker via the right femoral vein.

Research paper thumbnail of Enhanced dispersion of atrial refractoriness as an electrophysiological substrate for vulnerability to atrial fibrillation in patients with paroxysmal atrial fibrillation

Revista portuguesa de cardiologia : orgão oficial da Sociedade Portuguesa de Cardiologia = Portuguese journal of cardiology : an official journal of the Portuguese Society of Cardiology

Atrial electrical remodeling plays a part in recurrence of atrial fibrillation (AF). It has been ... more Atrial electrical remodeling plays a part in recurrence of atrial fibrillation (AF). It has been related to an increase in heterogeneity of atrial refractoriness that facilitates the occurrence of multiple reentry wavelets and vulnerability to AF. To examine the relationship between dispersion of atrial refractoriness (Disp_A) and vulnerability to AF induction (A_Vuln) in patients with clinical paroxysmal AF (PAF). Thirty-six patients (22 male; age 55+/-13 years) with > or =1 year of history of PAF (no underlying structural heart disease--n=20, systemic hypertension--n=14, mitral valve prolapse--n=1, surgically corrected pulmonary stenosis--n=1), underwent electrophysiological study (EPS) while off medication. The atrial effective refractory period (AERP) was assessed at five different sites--high (HRA) and low (LRA) lateral right atrium, high interatrial septum (IAS), proximal (pCS) and distal (dCS) coronary sinus--during a cycle length of 600 ms. AERP was taken as the longest S...

Research paper thumbnail of Alterations in autonomic response head-up tilt testing in paroxysmal atrial fibrillation patients: a wavelet analysis

Revista portuguesa de cardiologia : orgão oficial da Sociedade Portuguesa de Cardiologia = Portuguese journal of cardiology : an official journal of the Portuguese Society of Cardiology, 2009

The autonomic nervous system (ANS) is known to be an important modulator in the pathogenesis of p... more The autonomic nervous system (ANS) is known to be an important modulator in the pathogenesis of paroxysmal atrial fibrillation (PAF). Changes in ANS control of heart rate variability (HRV) occur during orthostatism to maintain cardiovascular homeostasis. Wavelet transform has emerged as a useful tool that provides time-frequency decomposition of the signal under investigation, enabling intermittent components of transient phenomena to be analyzed. To study HRV during head-up tilt (HUT) with wavelet transform analysis in PAF patients and healthy individuals (normals). Twenty-one patients with PAF (8 men; age 58 +/- 14 yrs) were examined and compared with 21 normals (7 men, age 48 +/- 12 yrs). After a supine resting period, all subjects underwent passive HUT (60 degrees) while in sinus rhythm. Continuous monitoring of ECG and blood pressure was carried out (Task Force Monitor, CNSystems). Acute changes in RR-intervals were assessed by wavelet analysis and low-frequency power (LF: 0.04...

Research paper thumbnail of Effects of stimulation and blockade of the autonomic nervous system on atrial refractoriness in patients with lone paroxysmal atrial fibrillation

Revista portuguesa de cardiologia : orgão oficial da Sociedade Portuguesa de Cardiologia = Portuguese journal of cardiology : an official journal of the Portuguese Society of Cardiology, 2009

Heterogeneous shortening of the atrial effective refractory period (AERP) and increased dispersio... more Heterogeneous shortening of the atrial effective refractory period (AERP) and increased dispersion of refractoriness (disp_A) predispose to recurrent episodes of atrial fibrillation (AF). To evaluate the effects of stimulation and blockade of the autonomic nervous system (ANS) on atrial refractoriness in patients with > or = 1 year clinical history of lone paroxysmal AF (PAF). Ten patients (6 men, aged 55 +/- 14 years) underwent electrophysiological study while off medication. AERP was assessed at 5 sites--right atrial appendage (RAA) and low lateral right atrium (LRA), high interatrial septum (IAS), proximal (pCS) and distal (dCS) coronary sinus in basal conditions, during handgrip (HG) and carotid sinus massage (CSM), and after ANS blockade (ANSB) (atropine 0.04 mg/kg + propranolol 0.15 mg/kg). The AERP was taken as the longest S1-S2 interval that failed to initiate a response. Disp_A was calculated as the difference between the longest and shortest AERP. RR intervals were 853 ...

Research paper thumbnail of Utility of continuous monitoring of heart rate variability in the early detection of heart failure decompensation

Revista portuguesa de cardiologia: orgao oficial da Sociedade Portuguesa de Cardiologia = Portuguese journal of cardiology: an official journal of the Portuguese Society of Cardiology

Research paper thumbnail of Long-term clinical outcome in patients with severe left ventricular dysfunction and an implantable cardioverter-defibrillator after ventricular tachyarrhythmias

Revista portuguesa de cardiologia : orgão oficial da Sociedade Portuguesa de Cardiologia = Portuguese journal of cardiology : an official journal of the Portuguese Society of Cardiology, 2005

Left ventricular ejection fraction (LVEF) is accepted as an important prognostic marker in patien... more Left ventricular ejection fraction (LVEF) is accepted as an important prognostic marker in patients (pts) with implantable cardioverter-defibrillators (ICD). The impact of this therapeutic approach in the survival of pts with life-threatening arrhythmias and severe left ventricular dysfunction remains a matter of discussion. To evaluate the long-term clinical implications of severe left ventricular dysfunction in pts with an ICD implanted for secondary prevention of sudden cardiac death (SD). Out of 70 pts undergoing ICD implantation in our institution over four consecutive years, we studied 24 pts with LVEF <35% and a post-ICD follow-up of >12 months (87.5% male; age 62.79 years). The index arrhythmia was ventricular tachycardia in 19 cases and SD with ventricular fibrillation in 5 cases. The underlying disease was ischemic cardiomyopathy (n=19), dilated cardiomyopathy (n=4) and hypertensive heart disease (n=1). Mean LVEF at the time of implant was 25 +/- 7% (between 11% and ...

Research paper thumbnail of False positive responses to head-up tilt testing in elderly patients with paroxysmal atrial fibrillation

Revista portuguesa de cardiologia : orgão oficial da Sociedade Portuguesa de Cardiologia = Portuguese journal of cardiology : an official journal of the Portuguese Society of Cardiology, 2008

The autonomic nervous system (ANS) plays a role as a modulator in the pathogenesis of paroxysmal ... more The autonomic nervous system (ANS) plays a role as a modulator in the pathogenesis of paroxysmal atrial fibrillation (PAF). The clinical pattern of vagally mediated PAF has been observed mainly in young patients. Neurocardiogenic responses during orthostatic stress are related to autonomic reflexes in which the vagal influence predominates. To evaluate the susceptibility of elderly patients with PAF to activation of vasovagal syncope mechanisms. We performed passive head-up tilt testing (HUT) in 34 patients (62% women, aged 72 +/- 7 years), with > or = 1 year of clinical history of PAF--19 without structural heart disease, 11 with hypertensive heart disease and 4 with coronary artery disease (who had no previous myocardial infarction, had undergone myocardial revascularization, and had no documented ischemia) (PAF group), and compared the results with those obtained in a group of 34 age-matched patients (53% women, aged 74 +/- 6 years), who underwent HUT due to recurrent syncope ...

Research paper thumbnail of P1461Risk of atrial fibrillation after catheter ablation of typical atrial flutter: a long-term outcome study

EP Europace, 2017

The apnea-hypopnea index decreased significantly after RFCA (baseline 28.7613.9, after RFCA 20.76... more The apnea-hypopnea index decreased significantly after RFCA (baseline 28.7613.9, after RFCA 20.7613.2, P<0.001) in OSA group. The prevalence of recurrence of AF at 1-year follow-up was equivalent between the two groups (OSA group: 20%, no OSA group: 21%). Conclusions: RFCA for paroxysmal AF decreased the apnea-hypopnea index. Neural ablation may contribute to improve sleep-disordered breathing and RFCA success rate in patients with OSA.

Research paper thumbnail of Alterations in autonomic response during head-up tilt testing in paroxysmal atrial fibrillation patients: A wavelet analysis

Revista portuguesa de cardiologia: orgao oficial da Sociedade Portuguesa de Cardiologia = Portuguese journal of cardiology: an official journal of the Portuguese Society of Cardiology

ABSTRACT

Research paper thumbnail of R on T phenomenon

Revista portuguesa de cardiologia : orgão oficial da Sociedade Portuguesa de Cardiologia = Portuguese journal of cardiology : an official journal of the Portuguese Society of Cardiology

Research paper thumbnail of Remote monitoring for follow-up of patients with implantable cardiac devices

Revista Portuguesa de Cardiologia (English Edition), 2013

With a widening of indications for cardiac devices, especially in view of the clinical benefits o... more With a widening of indications for cardiac devices, especially in view of the clinical benefits of implantable cardioverter-defibrillators and cardiac resynchronization therapy, the number of patients with such devices is growing steadily. However, the resources required, and the need for long-term regular interrogation in dedicated clinics, represent a significant burden for already overstretched electrophysiology teams and hospital services. Remote telemonitoring is increasingly used for such follow-up, as it is a safe and effective alternative to conventional follow-up programs in outpatient clinics. This technology has been shown to be technically reliable, enabling early identification of device malfunction, arrhythmic events and heart failure decompensation, while reducing the risk of under-reporting, the number of outpatient clinic visits and hospitalizations due to cardiac events, and healthcare costs. Further studies are needed to determine how best to implement this new technology in a cost-effective manner, and what new legislation governing the use of remote monitoring in clinical practice may be required. In this article, we describe current systems, review the technical and clinical evidence in the literature regarding remote monitoring of implantable cardiac devices, and expand on outstanding questions.

Research paper thumbnail of Impacto da terapia de ressincronização cardíaca na qualidade de vida em doentes com insuficiência cardíaca congestiva refractária

Research paper thumbnail of Influência do género na qualidade de vida em doentes com insuficiência cardíaca

Research paper thumbnail of Inducibility of atrial fibrillation during electrophysiologic evaluation is associated with increased dispersion of atrial refractoriness

International Journal of Cardiology, 2009

The impact of atrial dispersion of refractoriness (Disp_A) in the inducibility and maintenance of... more The impact of atrial dispersion of refractoriness (Disp_A) in the inducibility and maintenance of atrial fibrillation (AF) has not been fully resolved. Aim: To study the Disp_A and the vulnerability (A_Vuln) for the induction of self-limited (b 60 s) and sustained episodes of AF. Methods and results: Forty-seven patients with paroxysmal AF (PAF): 29 patients without structural heart disease and 18 with hypertensive heart disease. Atrial effective refractory period (ERP) was assessed at five sites-right atrial appendage and low lateral right atrium, high interatrial septum, proximal and distal coronary sinus. We compared three groups: group A-AF not inducible (n = 13); group B-AF inducible, self-limited (n = 18); group C-AF inducible, sustained (n = 16). Age, lone AF, hypertension, left atrial and left ventricular (LV) dimensions, LV systolic function, duration of AF history, atrial flutter/tachycardia, previous antiarrhythmics, and Disp_A were analysed with logistic regression to determine association with A_Vuln for AF inducibility. The ERP at different sites showed no differences among the groups. Group A had a lower Disp_A compared to group B (47 ± 20 ms vs 82 ± 65 ms; p = 0.002), and when compared to group C (47 ± 20 ms vs 80 ± 55 ms; p = 0.008). There was no significant difference in Disp_A between groups B and C. By means of multivariate regression analysis, the only predictor of A_Vuln was Disp_A (p = 0.04). Conclusion: In patients with PAF, increased Disp_A represents an electrophysiological marker of A_Vuln. Inducibility of both self-limited and sustained episodes of AF is associated with similar values of Disp_A. These findings suggest that the maintenance of AF is influenced by additional factors.

Research paper thumbnail of False positive responses to head-up tilt testing in elderly patients with paroxysmal atrial fibrillation

Revista portuguesa de cardiologia : orgão oficial da Sociedade Portuguesa de Cardiologia = Portuguese journal of cardiology : an official journal of the Portuguese Society of Cardiology, 2008

The autonomic nervous system (ANS) plays a role as a modulator in the pathogenesis of paroxysmal ... more The autonomic nervous system (ANS) plays a role as a modulator in the pathogenesis of paroxysmal atrial fibrillation (PAF). The clinical pattern of vagally mediated PAF has been observed mainly in young patients. Neurocardiogenic responses during orthostatic stress are related to autonomic reflexes in which the vagal influence predominates. To evaluate the susceptibility of elderly patients with PAF to activation of vasovagal syncope mechanisms. We performed passive head-up tilt testing (HUT) in 34 patients (62% women, aged 72 +/- 7 years), with > or = 1 year of clinical history of PAF--19 without structural heart disease, 11 with hypertensive heart disease and 4 with coronary artery disease (who had no previous myocardial infarction, had undergone myocardial revascularization, and had no documented ischemia) (PAF group), and compared the results with those obtained in a group of 34 age-matched patients (53% women, aged 74 +/- 6 years), who underwent HUT due to recurrent syncope ...

Research paper thumbnail of Sequências Short-Long-Short Como Indutores de Taquicardia Ventricular

Revista Portuguesa De Cardiologia, Jan 12, 2011

Research paper thumbnail of Alterations in autonomic response during head-up tilt testing in paroxysmal atrial fibrillation patients: A wavelet analysis

Revista portuguesa de cardiologia: orgao oficial da Sociedade Portuguesa de Cardiologia = Portuguese journal of cardiology: an official journal of the Portuguese Society of Cardiology

ABSTRACT

Research paper thumbnail of Hemodynamic device-based optimization in cardiac resynchronization therapy: concordance with systematic echocardiographic assessment of AV and VV intervals

Research Reports in Clinical Cardiology, 2015

Research paper thumbnail of Short QT syndrome presenting as syncope: How short is too short?

Revista Portuguesa de Cardiologia (English Edition), 2014

We report the case of a 52-year-old man who presented to our emergency department (ED) after thre... more We report the case of a 52-year-old man who presented to our emergency department (ED) after three episodes of syncope in the seven hours before admission. During his stay in the ED he had recurrent ventricular tachycardia (VT) requiring external electrical cardioversion. A 12-lead electrocardiogram (ECG) showed a short QT (SQT) interval (270 ms, QTc 327 ms), with frequent R-on-T extrasystoles triggering sustained polymorphic VT. After exclusion of other precipitating causes, the patient was diagnosed as having SQT syndrome (SQTS) according to the Gollob criteria. To our knowledge, this is the first known documentation of an SQT-caused arrhythmic episode on a 12-lead ECG, as well as the first reported case of SQTS in Portugal. The patient received an implantable cardioverter-defibrillator and was discharged. At a follow-up assessment 14 months later he was symptom-free, interrogation of the device showed no arrhythmic events, and the ECG showed a QT interval of 320 ms (QTc 347 ms).

Research paper thumbnail of Assessment of T-wave alternans after acute myocardial infarction: influence of the timing of PTCA on cardiac electrical stabilization

Revista portuguesa de cardiologia : orgão oficial da Sociedade Portuguesa de Cardiologia = Portuguese journal of cardiology : an official journal of the Portuguese Society of Cardiology, 2006

It is accepted that the timing of myocardial revascularization in patients undergoing PTCA for th... more It is accepted that the timing of myocardial revascularization in patients undergoing PTCA for the treatment of acute myocardial infarction (AMI) may improve the clinical outcome. However, its impact on microvolt T-wave alternans (TWA), a recognized tool for assessing vulnerability to ventricular tachyarrhythmias that can cause sudden cardiac death in infarction survivors, remains unknown. To analyze TWA in patients with AMI treated by PTCA and assess whether the timing of myocardial revascularization can influence TWA measurements. We studied 79 patients (67 male; 57 +/- 11 years) who underwent successful PTCA for the treatment of AMI. The presence of TWA was assessed using a HearTwave system (Cambridge Heart, Inc.) within 30 days of AMI. Orthogonal Frank XYZ leads and associated vector magnitude (microvolt alternans sensors) and 7 standard ECG leads were recorded during a treadmill manual exercise protocol to increase heart rate slowly to approximately 110 bpm. TWA was considered ...

Research paper thumbnail of Acesso femoral venoso: uma alternativa excecional para a implantação de pacemaker definitivo

Revista Portuguesa de Cardiologia, 2014

The classic transvenous implantation of a permanent pacemaker in a pectoral location may be precl... more The classic transvenous implantation of a permanent pacemaker in a pectoral location may be precluded by obstruction of venous access through the superior vena cava or recent infection at the implant site. When these barriers to the procedure are bilateral and there are also contraindications or technical difficulties to performing a thoracotomy for an epicardial approach, the femoral vein, although rarely used, can be a viable alternative. We describe the case of a patient with occlusion of both subclavian veins and a high risk for mini-thoracotomy or videothoracoscopy, who underwent implantation of a permanent single-chamber pacemaker via the right femoral vein.

Research paper thumbnail of Enhanced dispersion of atrial refractoriness as an electrophysiological substrate for vulnerability to atrial fibrillation in patients with paroxysmal atrial fibrillation

Revista portuguesa de cardiologia : orgão oficial da Sociedade Portuguesa de Cardiologia = Portuguese journal of cardiology : an official journal of the Portuguese Society of Cardiology

Atrial electrical remodeling plays a part in recurrence of atrial fibrillation (AF). It has been ... more Atrial electrical remodeling plays a part in recurrence of atrial fibrillation (AF). It has been related to an increase in heterogeneity of atrial refractoriness that facilitates the occurrence of multiple reentry wavelets and vulnerability to AF. To examine the relationship between dispersion of atrial refractoriness (Disp_A) and vulnerability to AF induction (A_Vuln) in patients with clinical paroxysmal AF (PAF). Thirty-six patients (22 male; age 55+/-13 years) with > or =1 year of history of PAF (no underlying structural heart disease--n=20, systemic hypertension--n=14, mitral valve prolapse--n=1, surgically corrected pulmonary stenosis--n=1), underwent electrophysiological study (EPS) while off medication. The atrial effective refractory period (AERP) was assessed at five different sites--high (HRA) and low (LRA) lateral right atrium, high interatrial septum (IAS), proximal (pCS) and distal (dCS) coronary sinus--during a cycle length of 600 ms. AERP was taken as the longest S...

Research paper thumbnail of Alterations in autonomic response head-up tilt testing in paroxysmal atrial fibrillation patients: a wavelet analysis

Revista portuguesa de cardiologia : orgão oficial da Sociedade Portuguesa de Cardiologia = Portuguese journal of cardiology : an official journal of the Portuguese Society of Cardiology, 2009

The autonomic nervous system (ANS) is known to be an important modulator in the pathogenesis of p... more The autonomic nervous system (ANS) is known to be an important modulator in the pathogenesis of paroxysmal atrial fibrillation (PAF). Changes in ANS control of heart rate variability (HRV) occur during orthostatism to maintain cardiovascular homeostasis. Wavelet transform has emerged as a useful tool that provides time-frequency decomposition of the signal under investigation, enabling intermittent components of transient phenomena to be analyzed. To study HRV during head-up tilt (HUT) with wavelet transform analysis in PAF patients and healthy individuals (normals). Twenty-one patients with PAF (8 men; age 58 +/- 14 yrs) were examined and compared with 21 normals (7 men, age 48 +/- 12 yrs). After a supine resting period, all subjects underwent passive HUT (60 degrees) while in sinus rhythm. Continuous monitoring of ECG and blood pressure was carried out (Task Force Monitor, CNSystems). Acute changes in RR-intervals were assessed by wavelet analysis and low-frequency power (LF: 0.04...

Research paper thumbnail of Effects of stimulation and blockade of the autonomic nervous system on atrial refractoriness in patients with lone paroxysmal atrial fibrillation

Revista portuguesa de cardiologia : orgão oficial da Sociedade Portuguesa de Cardiologia = Portuguese journal of cardiology : an official journal of the Portuguese Society of Cardiology, 2009

Heterogeneous shortening of the atrial effective refractory period (AERP) and increased dispersio... more Heterogeneous shortening of the atrial effective refractory period (AERP) and increased dispersion of refractoriness (disp_A) predispose to recurrent episodes of atrial fibrillation (AF). To evaluate the effects of stimulation and blockade of the autonomic nervous system (ANS) on atrial refractoriness in patients with > or = 1 year clinical history of lone paroxysmal AF (PAF). Ten patients (6 men, aged 55 +/- 14 years) underwent electrophysiological study while off medication. AERP was assessed at 5 sites--right atrial appendage (RAA) and low lateral right atrium (LRA), high interatrial septum (IAS), proximal (pCS) and distal (dCS) coronary sinus in basal conditions, during handgrip (HG) and carotid sinus massage (CSM), and after ANS blockade (ANSB) (atropine 0.04 mg/kg + propranolol 0.15 mg/kg). The AERP was taken as the longest S1-S2 interval that failed to initiate a response. Disp_A was calculated as the difference between the longest and shortest AERP. RR intervals were 853 ...

Research paper thumbnail of Utility of continuous monitoring of heart rate variability in the early detection of heart failure decompensation

Revista portuguesa de cardiologia: orgao oficial da Sociedade Portuguesa de Cardiologia = Portuguese journal of cardiology: an official journal of the Portuguese Society of Cardiology

Research paper thumbnail of Long-term clinical outcome in patients with severe left ventricular dysfunction and an implantable cardioverter-defibrillator after ventricular tachyarrhythmias

Revista portuguesa de cardiologia : orgão oficial da Sociedade Portuguesa de Cardiologia = Portuguese journal of cardiology : an official journal of the Portuguese Society of Cardiology, 2005

Left ventricular ejection fraction (LVEF) is accepted as an important prognostic marker in patien... more Left ventricular ejection fraction (LVEF) is accepted as an important prognostic marker in patients (pts) with implantable cardioverter-defibrillators (ICD). The impact of this therapeutic approach in the survival of pts with life-threatening arrhythmias and severe left ventricular dysfunction remains a matter of discussion. To evaluate the long-term clinical implications of severe left ventricular dysfunction in pts with an ICD implanted for secondary prevention of sudden cardiac death (SD). Out of 70 pts undergoing ICD implantation in our institution over four consecutive years, we studied 24 pts with LVEF <35% and a post-ICD follow-up of >12 months (87.5% male; age 62.79 years). The index arrhythmia was ventricular tachycardia in 19 cases and SD with ventricular fibrillation in 5 cases. The underlying disease was ischemic cardiomyopathy (n=19), dilated cardiomyopathy (n=4) and hypertensive heart disease (n=1). Mean LVEF at the time of implant was 25 +/- 7% (between 11% and ...

Research paper thumbnail of False positive responses to head-up tilt testing in elderly patients with paroxysmal atrial fibrillation

Revista portuguesa de cardiologia : orgão oficial da Sociedade Portuguesa de Cardiologia = Portuguese journal of cardiology : an official journal of the Portuguese Society of Cardiology, 2008

The autonomic nervous system (ANS) plays a role as a modulator in the pathogenesis of paroxysmal ... more The autonomic nervous system (ANS) plays a role as a modulator in the pathogenesis of paroxysmal atrial fibrillation (PAF). The clinical pattern of vagally mediated PAF has been observed mainly in young patients. Neurocardiogenic responses during orthostatic stress are related to autonomic reflexes in which the vagal influence predominates. To evaluate the susceptibility of elderly patients with PAF to activation of vasovagal syncope mechanisms. We performed passive head-up tilt testing (HUT) in 34 patients (62% women, aged 72 +/- 7 years), with > or = 1 year of clinical history of PAF--19 without structural heart disease, 11 with hypertensive heart disease and 4 with coronary artery disease (who had no previous myocardial infarction, had undergone myocardial revascularization, and had no documented ischemia) (PAF group), and compared the results with those obtained in a group of 34 age-matched patients (53% women, aged 74 +/- 6 years), who underwent HUT due to recurrent syncope ...