Effects of renal denervation on 24-h heart rate and heart rate variability in resistant hypertension.

BACKGROUND: Catheter-based renal sympathetic denervation (RDN) can reduce sympathetic activity and blood pressure (BP) in patients with hypertension. The present study aimed at investigating the effects of RDN on heart rate (HR), number of premature captions, and heart rate variability (HRV). METHODS: A total of 105 patients (67% male, age 63.5 ± 10 years) with resistant hypertension (BP 169 ± 22/89 ± 14 mmHg) underwent bilateral RDN using a radiofrequency catheter (Symplicity Flex, Medtronic). 24-h Holter monitoring was performed at baseline and after 6 months. Besides HR profile, the number of premature atrial (PAC) and ventricular captions (PVC), time and frequency domain-based HRV were analyzed. Data are presented as mean ± standard deviation or median (interquartile range). RESULTS: Office systolic and diastolic BP were reduced after RDN by 21.8 ± 25.2 mmHg and 8 ± 18.7 mmHg (p < 0.001 for both), respectively. Twenty-eight (27%) patients had a reduction of < 10 mmHg in systolic BP. At baseline, mean 24-h HR was 65.7 ± 9.9 bpm. The prevalence of PAC [median 1.2 (0.3-6.2)] and PVC [median 1.2 (0.1-13.9)] was low and values of HRV were within normal limits and not different between responders and non-responders. After 6 months, patients with a baseline HR > 72 min had a significant reduction in HR by 2.3 ± 7.1 bpm. Parameters of HRV did not significantly change during follow-up. In patients with ≥ 6 PAC per hour at baseline, a significant median reduction of - 12.4 (- 37.4 to - 2.3) PAC after 6 months was documented (p = 0.002), which occurred independently from BP effects. The number of PVC was not significantly altered after RDN. CONCLUSION: In patients with resistant hypertension and elevated HR or high burden of PACs, RDN was associated with a reduction of HR and number of PAC. Parameters of HRV were not changed after RDN nor were predictive of response to RDN.

Predictors of atrial ectopy and their relationship to atrial fibrillation risk.

AIMS: Premature atrial contractions (PACs) are known to trigger and predict atrial fibrillation (AF). We sought to identify the determinants of PACs and the degree to which PACs mediate the effects of established risk factors for AF. METHODS AND RESULTS: Predictors of baseline PAC frequency were examined using a Holter Study among 1392 participants in the Cardiovascular Health Study, a community-based cohort of individuals aged ≥65 years. Participants were then followed for their first diagnosis of AF. Independent predictors of PACs were identified, and the extent to which PACs might mediate the relationship between those predictors and AF was determined. The median hourly frequency of PACs was 2.7 (interquartile range 0.8-12.1). After multivariable adjustment, increasing age, increasing height, decreasing body mass index, and a history of myocardial infarction were each associated with more PACs. Regarding modifiable predictors, participants using beta-blockers had 21% less [95% confidence interval (95% CI) 9-30%, P = 0.001] and those performing at least moderate intensity exercise vs. lower intensity exercisers had 10% less (95% CI 1-18%, P = 0.03) PACs. Higher PAC frequency explained 34% (95% CI 22-57%, P < 0.0001) of the relationship between increasing age and AF risk and 27% (95% CI 10-75%, P = 0.004) of the relationship between taller height and AF risk. CONCLUSION: Enhancing physical activity and use of beta-blockers may represent fruitful strategies to mitigate PAC frequency. A substantial proportion of the excess risk of AF due to increasing age and taller height may be explained by an increase in PAC frequency.

Atrial Remodeling Following Catheter-Based Renal Denervation Occurs in a Blood Pressure- and Heart Rate-Independent Manner.

OBJECTIVES: This study sought to investigate left atrial (LA) remodeling in relation to blood pressure (BP) and heart rate (HR) after renal sympathetic denervation (RDN). BACKGROUND: In addition to reducing BP and HR in certain patients with hypertension, RDN can decrease left ventricular (LV) mass and ameliorate LV diastolic dysfunction. METHODS: Before and 6 months after RDN, BP, HR, LV mass, left atrial volume index (LAVI), diastolic function (echocardiography), and premature atrial contractions (PAC) (Holter electrocardiogram) were assessed in 66 patients with resistant hypertension. RESULTS: RDN reduced office BP by 21.6 ± 3.0/10.1 ± 2.0 mm Hg (p < 0.001), and HR by 8.0 ± 1.3 beats/min (p < 0.001). At baseline, LA size correlated with LV mass, diastolic function, and pro-brain natriuretic peptide, but not with BP or HR. Six months after RDN, LAVI was reduced by 4.0 ± 0.7 ml/kg/m(2) (p < 0.001). LA size decrease was stronger when LAVI at baseline was higher. In contrast, the decrease in LAVI was not dependent on LV mass or diastolic function (E/E' or E/A) at baseline. Furthermore, LAVI decreased without relation to decrease in systolic BP or HR. Additionally, occurrence of PAC (median of >153 PAC/24 h) was reduced (to 68 PAC/24 h) by RDN, independently of changes in LA size. CONCLUSIONS: In patients with resistant hypertension, LA volume and occurrence of PAC decreased 6 months after RDN. This decrease was independent of BP and HR at baseline or the reduction in BP and HR reached by renal denervation. These data suggest that there is a direct, partly BP-independent effect of RDN on cardiac remodeling and occurrence of premature atrial contractions.

Predictors of ectopic firing from the superior vena cava in patients with paroxysmal atrial fibrillation.

PURPOSE: Although catheter ablation targeting the pulmonary vein (PV) is a well-known therapy for patients with paroxysmal atrial fibrillation (PAF), ectopic firings from the superior vena cava (SVC) can initiate PAF. The purpose of this study was to investigate predictors of SVC firing. METHODS: The subjects included 336 consecutive PAF patients (278 males, age 56.1 ± 10.8 years) undergoing atrial fibrillation (AF) ablation. The appearance of SVC firing was monitored throughout the procedure using a decapolar catheter with multiple electrodes to record electrograms of the coronary sinus and SVC. In addition to PV isolation, SVC isolation was performed only in patients with documented SVC firing. RESULTS: SVC firing was observed in 43/336 (12.8 %) of the patients, among whom complete isolation of the SVC was achieved in 40/43 (93 %) patients. A lower body mass index (BMI) (22.8 ± 2.8 vs 24.1 ± 3.1 kg/m(2), p = 0.007) and higher prevalence of prior ablation procedures (58 vs 18 %, p = 0.0001) were related to the presence of SVC firing. In a multivariate analysis, a lower BMI (p = 0.012; odds ratio 0.83, 95 % CI 0.72 to 0.96) and history of prior ablation procedures (p < 0.0001; odds ratio 5.37, 95 % CI 2.71 to 10.63) were found to be independent predictors of the occurrence of SVC firing. Among 96 patients undergoing repeat ablation procedures, less PV-left atrial re-conduction was observed in patients with SVC firing than in those without (2.7 ± 1.2 vs 3.2 ± 0.8, p = 0.02). CONCLUSIONS: The presence of SVC firing in patients with PAF is associated with a history of repeat ablation procedures and lower BMI values.

Redução da densidade de extrassístoles e dos sintomas relacionados após administração de magnésio por via oral / Successful improvement of frequency and symptoms of premature complexes after oral magnesium administration

FUNDAMENTO: As extrassístoles ventriculares e supraventriculares (EV e ESSV) são frequentes e muitas vezes sintomáticas. O íon magnésio (Mg) desempenha um papel importante na fisiologia do potencial de ação transmembrana celular e do ritmo cardíaco. OBJETIVO: Avaliar se a administração do pidolato de magnésio (PMg) em pacientes com EV e ESSV tem desempenho superior ao uso do placebo (P) na melhora dos sintomas e densidade das extrassístoles (DES). MÉTODOS: Estudo duplo-cego, randomizado, com 60 pacientes sintomáticos consecutivos, com mais de 240/EV ou ESSV ao Holter de 24 horas e selecionados para receber P ou PMg. Para avaliar a melhora da sintomatologia, foi feito um questionário categórico e específico de sintomas relacionados às extrassístoles. Após o tratamento, foi considerada significante uma redução de mais de 70% na DES por hora. A dose do PMg foi de 3,0 g/dia por 30 dias, equivalente a 260 mg do elemento Mg. Nenhum paciente tinha cardiopatia estrutural ou insuficiência renal. RESULTADOS: Dos 60 pacientes estudados, 33 eram do sexo feminino (55%). A faixa etária variou de 16 a 70 anos. No grupo PMg, 76,6% dos pacientes tiveram redução maior que 70%, 10% deles maior que 50% e somente 13,4% tiveram redução menor que 50% na DES. No grupo P, 40% dos pacientes tiveram melhora de apenas 30% na frequência de extrassístoles (p < 0,001). A melhora dos sintomas foi alcançada em 93,3% dos pacientes do grupo PMg, comparada com somente 16,7% do grupo P (p < 0,001). CONCLUSÃO: A suplementação de Mg via oral reduziu a DES, resultando em melhora dos sintomas.

BACKGROUND: Premature ventricular and supraventricular complexes (PVC and PsVC) are frequent and often symptomatic. The magnesium (Mg) ion plays a role in the physiology of cell membranes and cardiac rhythm. OBJECTIVE:We evaluated whether the administration of Mg Pidolate (MgP) in patients with PVC and PsVC is superior to placebo (P) in improving symptoms and arrhythmia frequency. METHODS: Randomized double-blind study with 60 consecutive symptomatic patients with more than 240 PVC or PsVC on 24-hour Holter monitoring who were selected to receive placebo or MgP. To evaluate symptom improvement, a categorical and a specific questionnaire for symptoms related to PVC and PsVC was made. Improvement in premature complex density (PCD) per hour was considered significant if percentage reduction was >70% after treatment. The dose of MgP was 3.0 g/day for 30 days, equivalent to 260mg of Mg element. None of the patients had structural heart disease or renal failure. RESULTS: Of the 60 patients, 33 were female (55%). Ages ranged from 16 to 70 years old. In the MgP group, 76.6% of patients had a PCD reduction >70%, 10% of them >50% and only 13.4% <50%. In the P group, 40% showed slight improvement, <30%, in the premature complexes frequency (p < 0.001). Symptom improvement was achieved in 93.3% of patients in the MgP group, compared with only 16.7% in the P group (p < 0.001). CONCLUSION: Oral Mg supplementation decreases PCD, resulting in symptom improvement.

Successful improvement of frequency and symptoms of premature complexes after oral magnesium administration.

BACKGROUND: Premature ventricular and supraventricular complexes (PVC and PsVC) are frequent and often symptomatic. The magnesium (Mg) ion plays a role in the physiology of cell membranes and cardiac rhythm. OBJECTIVE: We evaluated whether the administration of Mg Pidolate (MgP) in patients with PVC and PsVC is superior to placebo (P) in improving symptoms and arrhythmia frequency. METHODS: Randomized double-blind study with 60 consecutive symptomatic patients with more than 240 PVC or PsVC on 24-hour Holter monitoring who were selected to receive placebo (P) or MgP. To evaluate symptom improvement, a categorical and a specific questionnaire for symptoms related to PVC and PsVC was made. Improvement in premature complex density (PCD) per hour was considered significant if percentage reduction was >70% after treatment. The dose of MgP was 3.0 g/day for 30 days, equivalent to 260 mg of Mg element. Any patient had structural heart disease or renal failure. RESULTS: Of the 60 patients, 33 were female (55%). Ages ranged from 16 to 70 years old. In the MgP group, 76.6% of patients had a PCD reduction >70%, 10% of them >50% and only 13.4% <50%. In the P group, 40% showed slight improvement, <30%, in the PC frequency (p < 0.001). Symptom improvement was achieved in 93.3% of patients in the MgP group, compared with only 16.7% in the P group (p < 0.001). CONCLUSION: Oral Mg supplementation decreases PCD, resulting in symptom improvement.

Influence of patient-controlled i.v. analgesia with opioids on supraventricular arrhythmias after pulmonary resection.

BACKGROUND: Postoperative supraventricular arrhythmias (SVA) are common after pulmonary resection and autonomic imbalance is thought to be one of the triggers. Opioids can increase parasympathetic activity and may balance heightened sympathetic tone after operation. We have examined the effect of postoperative patient-controlled analgesia (PCA) with opioids on postoperative SVA. METHODS: Forty-eight patients were randomly assigned to two groups. The GA group received general anaesthesia PCA and PCA with opioids (fentanyl 6 microg ml(-1) and tramadol 3 mg ml(-1)). The GEA group received combined general/epidural anaesthesia plus patient-controlled epidural analgesia (PCEA). Holter recording was completed for 12 h before operation and 12 and 48 h after operation. The incidence of supraventricular tachycardias (SVT), atrial fibrillation, and supraventricular ectopic beats (SVEBs) was evaluated. RESULTS: The incidence of postoperative SVT was significantly lower in the GA group than in the GEA group (3/22 vs 10/22, P=0.021). The incidence of postoperative SVEBs was not statistically different between the groups, but the frequency of postoperative SVEBs increased less in the GA than the GEA group (7/22 vs 15/22, P=0.016). CONCLUSIONS: PCA with opioids (fentanyl and tramadol) can reduce postoperative SVA after pulmonary resection compared with PCEA with ropivacaine.

Atrial premature complexes and heart rate have prognostic significance in 1-month atrial fibrillation recurrence after electrical cardioversion.

AIMS: The aim of this study was to investigate the significance of simple 24-h Holter (24H) data after electrical cardioversion (CV) for atrial fibrillation (AF) recurrence. METHODS: We prospectively studied 47 consecutive patients subjected to CV, who successfully converted to sinus rhythm. All underwent echocardiography and 24H after CV. AF recurrence was studied at 14 days and 1 month by second 24H or by interim report of AF. RESULTS: About 53.2% remained in sinus rhythm (group I) and the rest recurred to AF (group II). Group I had fewer atrial premature complexes per hour (APC/h) (P = 0.002) and lower maximum (max HR), average, and minimum heart rates compared with group II (all Ps < 0.05). The optimal value of APC/h and max HR with best sensitivity and specificity was 32 APC/h and 90 bpm, respectively. These findings were the predictors of AF recurrence [hazard ratio (HR) = 4.5 with 95% CI = 1.7-11.7 and HR = 4.3 with 95% CI = 1.7-10.9, respectively]. Patients with the combination of both predictors had greater HR of AF recurrence compared with those with < 32 APC/h and max HR < 90 bpm (HR = 8.8 with 95% CI = 2.5-31.4). CONCLUSION: Patients with frequent APC/h and high max HR are at high risk for 1-month AF recurrence after electrical CV.

Identification of "substrate fibrillators" and "trigger fibrillators" by pacemaker diagnostics.

BACKGROUND: The population of patients likely to respond to selected pacing algorithms for maintenance of sinus rhythm is unknown. OBJECTIVES: The purpose of this study was to identify patients with specific onset patterns of paroxysmal atrial fibrillation (AF). METHODS: Dual-chamber pacemakers with advanced diagnostic functions were implanted in 112 patients with conventional indications for antibradycardia pacing and a history of paroxysmal AF. Pacemaker diagnostic data were analyzed after 97.5 +/- 40.9 days. According to the frequency of premature atrial contractions (PACs) during the 5 minutes before AF onset, patients were assigned to one of three groups: group A (high PAC activity), group B (moderate PAC activity), or group C (low PAC activity). RESULTS: AF burden was lower in group A (4.6% +/- 2.4%) than group B (15.8% +/- 3.0%, P = .003) and group C (15.5% +/- 3.1%, P = .003). Fewer AF episodes occurred in group A (2.1 +/- 1.3 per day) than group B (3.8 +/- 1.2 per day, P = .006). Mean AF episode duration was shorter in group A (11.4 +/- 10.2 hours) than group C (41.4 +/- 27.5 hours, P = .03). CONCLUSION: The coincidence of low PAC activity before AF onset, high AF burden, and extended arrhythmia episode duration appears to be the consequence of a high atrial substrate factor. In these "substrate fibrillators," the efficacy of pacing algorithms for maintenance of sinus rhythm may be limited. In contrast, "trigger fibrillators" exhibiting low AF burden despite high PAC incidence may represent the target population for specific PAC-suppressing pacing algorithms.