Dalmo Antonio Ribeiro Moreira

6-Month Outcomes in Patients With Implantable Cardioverter-Defibrillators Undergoing Renal Sympathetic Denervation for the Treatment of Refractory Ventricular Arrhythmias.

OBJECTIVES This study aimed to assess 6-month outcomes in patients with implantable cardioverter-defibrillators (ICDs) undergoing renal sympathetic denervation (RSD) for refractory ventricular arrhythmias (VAs). BACKGROUND ICDs are generally indicated for patients at high risk of malignant VAs. Sympathetic hyperactivity plays a critical role in the development, maintenance, and aggravation of VAs. METHODS A total of 10 patients with refractory VA underwent RSD. Underlying conditions were Chagas disease (n = 6), nonischemic dilated cardiomyopathy (n = 2), and ischemic cardiomyopathy (n = 2). Information on the number of ventricular tachycardia (VT)/ventricular fibrillation (VF) episodes and device therapies (antitachycardia pacing/shocks) in the previous 6 months as well as 1 and 6 months post-treatment was obtained from ICD interrogation. RESULTS The median number of VT/VF episodes/antitachycardia pacing/shocks 6 months before RSD was 28.5 (range 1 to 106)/20.5 (range 0 to 52)/8 (range 0 to 88), respectively, and was reduced to 1 (range 0 to 17)/0 (range 0 to 7)/0 (range 0 to 3) at 1 month and 0 (range 0 to 9)/0 (range 0 to 7)/0 (range 0 to 3) at 6 months afterward, respectively. There were no major procedure-related complications. Two patients experienced sustained VT within the first week; in both cases, no further episodes occurred during follow-up. Two patients were nonresponders: 1 with persistent idioventricular rhythm and 1 with multiple renal arteries and incomplete ablation. Three patients died during follow-up. None of the deaths was attributed to VA. CONCLUSIONS In patients with ICDs and refractory VAs, RSD was associated with reduced arrhythmic burden with no procedure-related complications. Randomized controlled trials investigating RSD for treatment of refractory VAs in patients with increased sympathetic activity are needed.

Efeitos cardiovasculares da anestesia local com vasoconstritor durante exodontia em coronariopatas

OBJECTIVE: To evaluate the occurrence of variables detecting myocardial ischemia during or after dental treatment under anesthesia with vasoconstrictor (epinephrine). METHODS: A total of 54 coronary patients undergoing dental extraction under local anesthesia with or without vasoconstrictor were included. They were divided into two groups (by drawing envelopes): group I (27 patients) using anesthetics with vasoconstrictor, and group II (27 cases) without vasoconstrictor. 24-hour Holter monitoring, Doppler-echocardiogram before and after dental intervention, and determination of biochemical markers (CK-MB mass, CK-MB activity, and troponin T) before and 24 hours after dental extraction were performed in all patients. Heart rate and blood pressure were also measured in the pre, post-anesthesia and post-dental extraction phases. Doppler echocardiography assessed left ventricular segmental contractility and the occasional occurrence of mitral regurgitation. The usual pharmaceutical treatment prescribed by the cardiologist was maintained in all cases. RESULTS: Three patients in group I presented ST-segment depression (1.0 mm) during administration of anesthesia; two other patients in group I had CK-MB mass elevation, and ischemia was not observed in any other case, as assessed by the other methods. No chest pain, arrhythmias, occurrence or worsening of left ventricular segmental hypocontractility or mitral regurgitation were observed in the study. CONCLUSION: Dental extraction performed under anesthesia with 1:100,000 epinephrine does not imply additional ischemic risks, as long as performed with good anesthetic technique and maintenance of the pharmacological treatment prescribed by the cardiologist.

Renal Denervation Using an Irrigated Catheter in Patients with Resistant Hypertension: A Promising Strategy?

Background Systemic hypertension is an important public health problem and a significant cause of cardiovascular mortality. Its high prevalence and the low rates of blood pressure control have resulted in the search for alternative therapeutic strategies. Percutaneous renal sympathetic denervation emerged as a perspective in the treatment of patients with resistant hypertension. Objective To evaluate the feasibility and safety of renal denervation using an irrigated catheter. Methods Ten patients with resistant hypertension underwent the procedure. The primary endpoint was safety, as assessed by periprocedural adverse events, renal function and renal vascular abnormalities at 6 months. The secondary endpoints were changes in blood pressure levels (office and ambulatory monitoring) and in the number of antihypertensive drugs at 6 months. Results The mean age was 47.3 (± 12) years, and 90% of patients were women. In the first case, renal artery dissection occurred as a result of trauma due to the long sheath; no further cases were observed after technical adjustments, thus showing an effect of the learning curve. No cases of thrombosis/renal infarction or death were reported. Elevation of serum creatinine levels was not observed during follow-up. At 6 months, one case of significant renal artery stenosis with no clinical consequences was diagnosed. Renal denervation reduced office blood pressure levels by 14.6/6.6 mmHg, on average (p = 0.4 both for systolic and diastolic blood pressure). Blood pressure levels on ambulatory monitoring decreased by 28/17.6 mmHg (p = 0.02 and p = 0.07 for systolic and diastolic blood pressure, respectively). A mean reduction of 2.1 antihypertensive drugs was observed. Conclusion Renal denervation is feasible and safe in the treatment of resistant systemic arterial hypertension. Larger studies are required to confirm our findings.

Ablação da atividade simpática renal com cateter de ponta irrigada: uma opção atraente?

BACKGROUND: Catheter-based renal sympathetic denervation has emerged as an adjunct strategy to control refractory hypertension. No studies have yet compared the tissue effects of different catheters, powers and time periods of radiofrequency application, which was the objective of this study. METHODS: Six porcine renal arteries were sectioned in their longitudinal axis and placed in the flow chamber designed to simulate physiological renal flow conditions. The catheters were placed obliquely to the artery with constant contact pressure. Radiofrequency ablations were performed using three different catheters: 4 mm/5 F solid-tip electrode, 4 mm/7 F solid-tip electrode, and open irrigated-tip 4 mm/7 F electrode. Two different powers were used (8 W and 15 W) for 30, 60 and 120 seconds. RESULTS: A total of 18 ablations were performed. More significant nerve damage was observed with the 4 mm/5 F catheter and power of 8 W only when the application duration was extended to 120 seconds. On the other hand, significant nerve damage was observed with the 4 mm/7 F catheter with all power (8 W and 15 W) and duration (30, 60, and 120 seconds) options tested. Deeper lesions were observed with the use of the irrigated catheter, regardless of power and time periods of radiofrequency application. CONCLUSIONS: The irrigated-tip catheters produce deeper lesions than solid-tip catheters and their use might be more beneficial in treating patients with renal sympathetic denervation. The clinical applicability of these results, however, should be confirmed.

Unilateral Renal Artery Sympathetic Denervation May Reduce Blood Pressure in Patients With Resistant Hypertension

A 29-year-old woman with essential resistant systemic hypertension for 17 years was referred for catheterbased renal sympatethic denervation (RSD). Despite optimal medical therapy including 9 different antihypertensive drugs (thiazides, angiotensin-converting enzyme inhibitors, calcium channel blockers, espironolactone, a-agonists, hidralazine, b-blockers, a-blockers, and amiloride), her mean blood pressure (BP) was 142/ 102 mm Hg (ambulatory BP monitoring measurement). The patient was hospitalized for 1 week before the procedure to exclude the diagnosis of pseudo-resistant hypertension. The benefits and complications were explained in detail before signing informed consent. Under conscious sedation, an 8F-long sheath was introduced into the right femoral artery and advanced to the aorta. Bilateral angiography revealed a left renal artery with a diameter of 5.2 mm and length of 10.9 mm and a right renal artery with a diameter of 5.1 mm and a length of 24 mm. A total of 5 lesions were circumferentially applied to the right renal artery with a distance of at least 5 mm between each lesion using an open-irrigated catheter. The duration of each lesion was 60 seconds. Satisfactory impedance drop was observed during each ablation point signifying appropriate tissue heating. At the end of the ablation, dye injection demonstrated signs of dissection most likely due to trauma caused by the long sheath at the ostia. A stent was immediately deployed with success and there were no apparent complications. Given that, in addition to unfavorable left renal artery anatomy, the decision was made to stop the procedure. The catheters were removed and manual compression was carried out. The patient was discharged 3 days later in stable condition and on 2 antihypertensive drugs. At 1-month follow-up, one more antihypertensive agent was added to the therapy (BP = 146/106 mm Hg). Ambulatory BP monitoring at 3 months demonstrated a mean BP of 133/ 82 mm Hg. At 6 months, the patient was still taking 3 medications, and mean BP was 132/78 mm Hg (Table). Renal angiography at 6 months revealed patent stent and no renal artery abnormalities. DISCUSSION This unique case suggests that unilateral catheter-based RSD may reduce BP in patients with resistant hypertension. Radiofrequency catheter ablation has been used for the treatment of cardiac arrhythmias for several decades. Recent studies have shown benefits of catheterbased RSD as an alternative strategy for BP control in patients with resistant chronic hypertension. Lesion formation depends on several factors such as proper electrode-tissue contact, power and duration applied, and type of catheter used, among others. In several clinical settings such as left ventricular tachycardia ablation, it is crucial to generate lesions deeply enough to penetrate into the myocardial tissue. However, excessive electrode tip temperature may lead to coagulum and char formation, which limits power delivery. That being said, many efforts have been undertaken in order to optimize power delivery into the myocardial tissue without exceeding electrode tip temperature. Irrigation of the catheter tip has been developed and is now a well-established method to enhance the depth of tissue penetration of radiofrequency energy without causing excessive electrode tip temperature, and therefore enlarging lesion size. Considering the location of the renal nerves deep into the adventitia, we hypothesized that the use of irrigated catheters could be more beneficial than solid-tip catheters in this setting. This could explain the better results observed in this case compared with previous published data. 1 On the other hand, our results are consistent with the publication of Ahmed and colleagues in which 10 patients with resistant hypertension underwent bilateral RSD with a saline-irrigated radiofrequency catheter. The authors showed reduction in the systolic/diastolic blood pressure of 21/11 mm Hg. 2 Large studies, however, need to be performed to demonstrate consistent benefit.

[Electrical cardioversion and myocardial injury: evaluation by new cardiac injury markers].

OBJECTIVE Evaluate, based on the evolution of new biochemical markers of cardiac damage, if electrical cardioversion (ECV) causes myocardial injury. METHODS Seventy-six patients (P) submitted to elective ECV for atrial fibrillation or atrial flutter were evaluated. Creatine phosphokinase (CPK), CK-MB activity, CK-MB mass, myoglobin and cardiac troponin I (cTnI) were measured before, and 6 and 24 hours after ECV. RESULTS ECV was successful in 58 P (76.3%). Cumulative energy (CE) was up to 350 joules (J) in 36 P, from 500 to 650 J in 20 P and from 900 to 960 J in 20 P; the mean energy delivered being 493 J (+/- 309). The levels of cTnI remained within normal limits in all 76 P. The increase of cumulative energy led to an elevation of CPK levels (> p value = 0.007), CK-MB activity (> p value = 0.002), CK-MB mass (> p value = 0.03), and myoglobin (> p value = 0.015). A positive correlation between the cumulative energy and CPK peaks was observed (r = 0.660; p < 0.001), CK-MB activity (r = 0.429; p < 0.0001), CK-MB mass (r = 0.265; p = 0.02), and myoglobin (r = 0.684; p < 0.0001), as well as between the number of shocks and the CPK peaks (r = 0.770; p < 0.001), CK-MB activity (r = 0.642; p < 0.0001), CK-MB mass (r = 0.430; p < 0.0001), and myoglobin (r = 0.745; p < 0.0001). CONCLUSION ECV does not cause myocardial injury detectable by cTnI measurement. Elevations of CPK, CK-MB activity, CK-MB mass and myoglobin result from skeletal muscle injury and are positively correlated with the CE delivered or with the number of shocks.OBJECTIVE: Evaluate, based on the evolution of new biochemical markers of cardiac damage, if electrical cardioversion (ECV) causes myocardial injury. METHODS: Seventy-six patients (P) submitted to elective ECV for atrial fibrillation or atrial flutter were evaluated. Creatine phosphokinase (CPK), CK-MB activity, CK-MB mass, myoglobin and cardiac troponin I (cTnI) were measured before, and 6 and 24 hours after ECV. RESULTS: ECV was successful in 58 P (76.3%). Cumulative energy (CE) was up to 350 joules (J) in 36 P, from 500 to 650 J in 20 P and from 900 to 960 J in 20 P; the mean energy delivered being 493 J (± 309). The levels of cTnI remained within normal limits in all 76 P. The increase of cumulative energy led to an elevation of CPK levels (> p value = 0.007), CK-MB activity (> p value = 0.002), CK-MB mass (> p value = 0.03), and myoglobin (> p value = 0.015). A positive correlation between the cumulative energy and CPK peaks was observed (r = 0.660; p < 0.001), CK-MB activity (r = 0.429; p < 0.0001), CK-MB mass (r = 0.265; p = 0.02), and myoglobin (r = 0.684; p < 0.0001), as well as between the number of shocks and the CPK peaks (r = 0.770; p < 0.001), CK-MB activity (r = 0.642; p < 0.0001), CK-MB mass (r = 0.430; p < 0,0001), and myoglobin (r = 0.745; p < 0.0001). CONCLUSION: ECV does not cause myocardial injury detectable by cTnI measurement. Elevations of CPK, CK-MB activity, CK-MB mass and myoglobin result from skeletal muscle injury and are positively correlated with the CE delivered or with the number of shocks.

Denervação simpática renal e qualidade de vida

BACKGROUND: Renal sympathetic denervation (RSD) is a promising strategy in the treatment of resistant hypertension. No studies have assessed the effect of RSD on quality of life in our country, which was the aim of this study. METHODS: The EuroQol-5 Dimensions questionnaire (EQ-5D-5L) was chosen to evaluate quality of life in 10 patients undergoing RSD, and it was applied before and 3 months after the procedure. RESULTS: Mean age was 47.3 ± 12 years and 90% of the patients were female. Baseline blood pressure was 187 ± 37.5/104 ± 18.5 mmHg and the number of antihypertensive drugs was 7.6 ± 1.3. Before the procedure, the value assigned to health status was 37.5 ± 22.7, increasing at 3 months to 70.5 ± 20.9 (P = 0.01). In the follow-up, in addition to a decrease in the number of antihypertensive drugs (7.6 ± 1.3 vs. 6 ± 2.2; P = 0.05), a trend towards reduced levels of systolic blood pressure (187 ± 36 mmHg vs 170 ± 44 mmHg; P = 0.10) and diastolic blood pressure (104 ± 18 mmHg vs 98 ± 20 mmHg; P = 0.20) was observed. Health status improvement resulted from a reduction of problems related to mobility, usual activities, pain/discomfort and anxiety/depression. The magnitude of blood pressure reduction was not associated with improved quality in all of the patients. On the other hand, those who had a decrease in the number of antihypertensive drugs reported a better health status. CONCLUSIONS: Patients with resistant hypertension have poor health status scores. RSD improved quality of life in most patients. Further studies are required to confirm consistent benefits.

Analysis of Circulating miR-1, miR-23a, and miR-26a in Atrial Fibrillation Patients Undergoing Coronary Bypass Artery Grafting Surgery

Atrial fibrillation (AF) is the most common arrhythmia after cardiac surgery. From a pathophysiological point of view, a myriad of factors such as trauma, atrial dilation, ischemia, mechanical myopericarditis, autonomic imbalance, loss of connexins, AF nest remodeling, inflammation, sutures, and dysfunction caused by postextracorporeal circulation can contribute to postoperative atrial fibrillation (POAF) resulting in a longer hospital stay and consequently higher cost. Recent studies showed that short fragments of RNA, called microRNA (miRNA), can contribute to the development of several cardiovascular diseases, including AF. The aim of this study was to evaluate the levels of circulating miRNAs (miR‐1, ‐23a, and ‐26a) that can be involved in POAF. Patients submitted to coronary artery bypass graft surgery were grouped in POAF (24 patients) and without POAF (24 patients). Results showed older age, longer clamp‐time, and more days in the intensive care unit as well as a longer total hospital stay in the POAF group. Preoperative levels of circulating miRNAs were similar. Analysis of miRNAs revealed significantly lower circulating levels of miRNA‐23a (P  =  0.02) and ‐26a (P  =  0.01) in the POAF group during the postoperative period. Receiver operating characteristic (ROC) analysis showed the area under the ROC curve of miR‐23a and miR‐26a for predicting FA was 0.63 (95% confidence interval [CI]: 0.51–0.74; P  =  0.02) and 0.66 (95% CI: 0.55–0.77; P  =  0.01), respectively. Our data suggests that circulating miRNA‐23a and ‐26a may be involved in the underlying biology of postoperative AF development.

Efeitos da estimulação com corrente elétrica contínua pulsátil sobre as propriedades eletrofisiológicas atriais: estudo experimental da fibrilação atrial em cães

OBJETIVO: Avaliar se a estimulacao atrial com corrente eletrica continua pulsatil induz fibrilacao atrial e os seus efeitos sobre as propriedades eletrofisiologicas atriais e as alteracoes histologicas atriais. METODOS: Foram submetidos a toracotomia lateral direita 22 caes e implantados eletrodos de marcapasso no sulcus terminalis (ST), apendice atrial direito (ADb) e na regiao postero-inferior do atrio esquerdo (AE); um par de eletrodos foi suturado na auriculeta direita para estimulacao com bateria alcalina de 9 Volts conectada a uma sistema (LM 555) que transforma a energia continua linear da bateria em corrente continua pulsatil, durante 60 min. A biopsia epicardica atrial foi realizada antes e apos a estimulacao atrial. RESULTADOS: Nao foram observadas diferencas nas duracoes dos periodos refratarios efetivos atriais. Os tempos de conducao intra-atrial, interatrial, bem como dos extra-estimulos atriais tambem prolongaram-se. A duracao dos eletrogramas atriais prolongou-se durante ritmo sinusal e estimulacao atrial programada; em 68% dos caes a fibrilacao atrial foi induzida e sustentou-se. Foram observados edema intersticial e bandas de contracao celular no subepicardio a microscopia optica, e intensa desorganizacao miofibrilar e aumento do tamanho das mitocondrias a microscopia eletronica. CONCLUSAO: Esta tecnica de estimulacao atrial induz fibrilacao atrial e provoca modificacoes atriais que aumentam sua vulnerabilidade para o surgimento de fibrilacao atrial.

Reproducibility for Heart Rate Variability Analysis during 6-Min Walk Test in Patients with Heart Failure and Agreement between Devices

Heart rate variability (HRV) analysis is a useful method to assess abnormal functioning in the autonomic nervous system and to predict cardiac events in patients with heart failure (HF). HRV measurements with heart rate monitors have been validated with an electrocardiograph in healthy subjects but not in patients with HF. We explored the reproducibility of HRV in two consecutive six-minute walk tests (6MW), 60-minute apart, using a heart rate monitor (PolarS810i) and a portable electrocardiograph (called Holter) in 50 HF patients (mean age 59 years, NYHA II, left ventricular ejection fraction ~35%). The reproducibility for each device was analysed using a paired t-test or the Wilcoxon signed-rank test. Additionally, we assessed the agreement between the two devices based on the HRV indices at rest, during the 6MW and during recovery using concordance correlation coefficients (CCC), 95% confidence intervals and Bland-Altman plots. The test-retest for the HRV analyses was reproducible using Holter and PolarS810i at rest but not during recovery. In the second 6MW, patients showed significant increases in rMSSD and walking distance. The PolarS810i measurements had remarkably high concordance correlation [0.86<CCC<0.99] based on Holter at rest, during 6MW and recovery. At higher rates, a small effect in increasing differences between Holter and Polar in R-R intervals was observed. In conclusion, our study showed good reproducibility of HRV at rest in two consecutive 6MW using Holter and PolarS810i. Additionally, PolarS810i produced good agreements in short-term HRV indices based on Holter simultaneous recordings at rest, during the 6MW and recovery in HF patients.