Plasma atrial natriuretic polypeptide concentrations during and after reversion of paroxysmal supraventricular tachycardias

Clinical presentation of paroxysmal supraventricular tachycardia: evaluation of usual and unusual symptoms

Objective

Clinical presentation of paroxysmal supraventricular tachycardia may vary from asymptomatic occurrence or mild perception of palpitation to severe chest pain or syncope. This variation is the most challenging issue in the diagnostic evaluation of rhythm disturbances and paroxysmal supraventricular tachycardia as well. This study sought to evaluate the symptoms during the tachycardia attack or index event in patients who underwent electrophysiological study and ablation procedure.

Methods

This retrospective study included 100 consecutive patients who underwent electrophysiological study and ablation procedures due to supraventricular tachycardia. Structural heart disease, moderate/severe valvular pathology, systemic pathologies, such as connective tissue disease and chronic obstructive lung disease, history of pacemaker implantation was defined as exclusion criteria. In addition, medically managed patients and patients with unsuccessful ablation were not included in the study.

Results

Palpitation was the most frequently observed symptom in 84% of patients, followed by chest pain in 47%, dyspnea in 38%, syncope 26%, lightheadedness in 19%, and sweating in 18% of the patients. The most common symptoms after tachycardia event were fatigue and lightheadedness with frequencies of 56% and 55%, respectively. Forty-five percent of the patients reported more than one, unusually frequent urination within the following 1-3 hours after the index event.

Conclusions

Paroxysmal supraventricular tachycardia might manifest itself as gastrointestinal, neurological, psychosomatic symptoms, and unusual complaints in association with or without main symptoms, including palpitation, chest pain, syncope, and dyspnea. Symptoms after tachycardia or index event should be questioned systematically.

Biomarkers and arrhythmia recurrence following radiofrequency ablation of atrial fibrillation

Objective

Atrial fibrillation (AF) is the most common cardiac arrhythmia, and radiofrequency catheter ablation of AF (RCAAF) has become increasingly popular. Cardiac stress and inflammation have been associated with AF. This study was performed to determine whether the pre- or post-AF ablation levels of high-sensitivity C-reactive protein (hs-CRP) and N-terminal pro–B-type natriuretic peptide (NT-proBNP) are predictive of AF recurrence.

Methods

This multicenter prospective cohort study involved patients undergoing RCAAF in Switzerland and Canada. The primary endpoint was the recurrence of AF or atrial flutter at 6 months.

Results

Of 202 patients, 195 completed follow-up (age, 57.5 ± 9 years; mean left ventricular ejection fraction, 62%; mean left atrial size, 19.4 cm²). Patients with AF recurrence had larger atrial surfaces and longer total RCAAF times. Both the pre-ablation hs-CRP level and 1-day post-RCAAF NT-proBNP level were significantly associated with an increased risk of recurrence.

Conclusions

The pre-ablation hs-CRP level and immediate post-ablation NT-proBNP level were markers for atrial arrhythmia recurrence after RCAAF. This confirms growing evidence of the role of inflammation in the pathogenesis of AF. These biomarkers appear to be promising stratification tools for selection and management of patients undergoing RCAAF.

Diagnostic challenges in supraventricular tachycardia: anticipating value of natriuretic peptides

It is important not to overlook supraventricular tachycardia (SVT) in patients complaining of palpitation or tachycardia-related symptoms but with normal ECG and heart rate in emergency department or outpatient clinics. The severity and presentation of symptoms is highly variable and depends on features including heart rate, duration of tachycardia, underlying heart disease, and individual patient perception. Early measurement of natriuretic peptides in patients presenting with palpitation and/or tachycardia-related symptoms would guide the clinician to rule out tachycardia and/or SVT. High levels of natriuretic peptides within 30 min of postattack period would certainly increase the likelihood of SVT.

What Is High Enough? Elevated NT-pro-BNP in Decompensated Paroxysmal Supraventricular Tachycardia

Since the late 1980s, elevated atrial natriuretic peptide (ANP) was considered the cause of brisk diuresis in adult patients with paroxysmal supraventricular tachycardia (PSVT). Pro-brain natriuretic peptide (pro-BNP) and related molecules, e.g., N-terminal pro b-type natriuretic peptide (NT-pro-BNP) are known biomarkers of heart failure in adult patients from many causes with probable relevance in children. Perhaps, pro-BNP or related molecules such as NT-pro-BNP are useful in the management of PSVT in infants, thus hastening treatment in children who may otherwise significantly decompensate. Case series of one infant and two neonates presenting with cardiogenic shock and evidence of heart failure are presented. Cardiac monitoring or electrocardiogram (ECG) confirmed the presence of PSVT. Adenosine was administered resulting in successful chemical cardioversion with each case. Significantly elevated NT-pro-BNP levels correlated with heart failure prior to cardioversion. In each case, patients were discharged home with lower NT-pro-BNP levels and maintenance with a β-blocker. Due to documented relationships between elevated pro-BNP level and heart failure in adults, the authors measured the related biomarker NT-pro-BNP in each case, as the relationship could be similar in pediatric PSVT. Based on our experience with children in acute heart failure from other causes, NT-pro-BNP can increase to potentially extreme levels in infants. It appears to correlate with clinical signs of insufficient cardiac output, such as tachycardia, respiratory distress, and moribund appearance. Indeed, in the case series, extremely high NT-pro-BNP values were obtained when the patients appeared moribund from decompensated PSVT. The question arising from these observations is: At what level of elevated NT-pro-BNP, would patients be identified for cardioversion prior to appearance of other signs and symptoms? For each patient within the case series, NT-pro-BNP levels of approximately 20,000 pg/mL were indicative of decompensated heart failure, which was subsequently confirmed by examination of the patient. Further investigation is needed to determine the clinical significance of NT-pro-BNP and related peptides in pediatric patients with PSVT and intermittent PSVT. However, the possibility exists that an increase in NT-pro-BNP and related peptides could be a biomarker for cardiac decompensation after prolonged or intermittent PSVT, thereby shortening the time of diagnosis and intervention, and hence, potentially preventing morbidity, mortality, and extended hospitalization. Additional evidence-based research would help provide biomarker information during PSVT allowing practitioners to more objectively analyze risks.

Responses of cardiac natriuretic peptides after paroxysmal supraventricular tachycardia: ANP surges faster than BNP and CNP

Atrial natriuretic peptide (ANP) secretion increases after 30 min of paroxysmal supraventricular tachycardia (PSVT). Whether this phenomenon also applies to brain or C-type natriuretic peptides (BNP or CNP) remains unknown. Blood samples of 18 patients (41 ± 11 yr old; 4 men) with symptomatic PSVT and normal left ventricular systolic function (ejection fraction 65 ± 6%) were collected from the coronary sinus (CS) and the femoral artery (FA) before and 30 min after the induction, and 30 min after the termination of PSVT. The results showed that the ANP levels rose steeply after the PSVT and then reduced at 30 min after the termination (baseline vs. post-PSVT vs. posttermination: CS: 34.0 ± 29.6 vs. 74.1 ± 42.3 vs. 46.1 ± 32.9; FA: 5.9 ± 3.24 vs. 28.2 ± 20.7 vs. 10.0 ± 4.6 pg/ml; all P < 0.05). In contrast, compared with ANP, the increases of BNP and CNP in CS after the PSVT were less sharp, but continued to rise after the termination of tachycardia (BNP, 10.2 ± 6.4 vs. 11.3 ± 7.1 vs. 11.8 ± 7.9; CNP, 4.5 ± 1.2 vs. 4.9 ± 1.4 vs. 5.0 ± 1.4 pg/ml; all P < 0.05). The rise of BNP and CNP in FA was similarly less sharp after the PSVT and remained stationary after the termination. PSVT exerted differential effects on cardiac natriuretic peptide levels. ANP increased greater after a 30-min induced PSVT, but dropped faster after termination of PSVT, compared with BNP and CNP.

The diagnostic significance of NT-proBNP and troponin I in emergency department patients presenting with palpitations

OBJECTIVE

This prospective study investigated the diagnostic significance of the N-terminal pro-brain natriuretic (NT-proBNP) and troponin I peptides in emergency department patients presenting with palpitations.

METHODS

Two groups of patients with palpitations but without documented supraventricular tachycardia were compared: a group with supraventricular tachycardia (n = 49) and a control group (n = 47). Both groups were diagnosed using electrophysiological studies during the study period. Blood samples were obtained from all of the patients to determine the NT-proBNP and troponin I levels within the first hour following arrival in the emergency department.

RESULT

The mean NT-proBNP levels were 207.74±197.11 in supraventricular tachyarrhythmia group and 39.99±32.83 pg/mL in control group (p<0.001). To predict supraventricular tachycardia, the optimum NT-proBNP threshold was 61.15 pg/mL, as defined by the receiver operating characteristic (ROC) curve, with a non-significant area under the ROC curve of 0.920 (95% CI, 0.86-0.97, p<0.001). The NT-proBNP cut-off for diagnosing supraventricular tachycardia had 81.6% sensitivity and 91.5% specificity. Supraventricular tachycardia was significantly more frequent in the patients with NT-proBNP levels ≥61.15 pg/mL (n = 44, 90.9%, p>0.001). The mean troponin I levels were 0.17±0.56 and 0.01±0.06 pg/mL for the patients with and without supraventricular tachycardia, respectively (p<0.05). Of the 96 patients, 21 (21.87%) had troponin I levels ≥0.01: 2 (4.25%) in the control group and 19 (38.77%) in the supraventricular tachycardia group (p<0.001).

CONCLUSION

Troponin I and, in particular, NT-proBNP peptide were helpful for differentiating supraventricular tachycardia from non- supraventricular tachycardia palpitations. Further randomized, large, multicenter trials are needed to define the benefit and diagnostic role of NT-proBNP and troponin I in the management algorithm of patients presenting with palpitations in emergency departments.

Circulating surfactant protein-B levels increase acutely in response to exercise-induced left ventricular dysfunction

1. As a result of its enormous surface area and necessary thinness for gas exchange, the alveolocapillary barrier is vulnerable to mechanical disruption from raised pulmonary microvascular pressure (Pmv). 2. Because surfactant protein-B (SP-B) leaks into the blood stream from the alveoli in response to alveolocapillary barrier damage and exercise leads to increased Pmv, we sought to determine whether exercise results in increased plasma SP-B. Moreover, in the setting of exercise-induced left ventricular dysfunction, the consequent increase in left heart filling pressure and, therefore, P(mv) would be expected to further increase plasma SP-B levels. 3. Twenty consecutive subjects referred for treadmill exercise stress echocardiography (ESE) had venous blood sampled immediately before and after ESE for batch atrial natriuretic peptide (ANP) and SP-B assay. Echocardiographic measures of pulmonary haemodynamics (pulmonary artery flow acceleration time (pafAT) and right ventricular outflow tract velocity time integral (rVTI)) were also taken pre- and post-exercise. 4. Although circulating ANP levels increased following exercise (P < 0.001), there was no change in circulating SP-B levels in the entire cohort. 5. Ten subjects had a positive ESE for ventricular dysfunction. Although circulating ANP was increased post-exercise in both the negative and positive ESE groups (P < 0.05 and P < 0.01, respectively), circulating SP-B only increased post-exercise in the positive ESE group (P < 0.05). Echocardiographic parameters supported an increment in P(mv) in the cohort with exercise-induced left ventricular dysfunction because this group had an increase in pafAT (P < 0.05; reflecting pulmonary artery pressure) and no change in rVTI. 6. Physical exertion associated with a Bruce protocol ESE is insufficient to increase circulating SP-B, despite evidence of increased left atrial and pulmonary vascular pressure. However, in the setting of exercise-induced myocardial dysfunction, there is a detectable increase in circulating SP-B. 7. The exaggerated increase in pulmonary vascular pressure in exercise-induced myocardial dysfunction may result in increased SP-B leakage from the alveoli into the circulation by altering the integrity of the alveolocapillary barrier to protein.

The Role of Endothelin in Mediating Ischemia/Hypoxia-Induced Atrial Natriuretic Peptide Release

The aim of the present study was to investigate the putative role of endothelin (ET) in mediating ischemia/hypoxia-induced ANP release utilizing exogenous ET-1 or ET receptor antagonists (BQ-123 or Bosentan). Isolated rat hearts with non-distended atria were perfused using a Langendorff apparatus and heart rate maintained constant via atrial pacing. Global ischemia was induced either by direct reduction in perfusion or by infusion of exogenous ET-1 (5 x 10(-10) M) for 30 minutes. Perfusion with the ET receptor antagonists, BQ-123 (10(-6) M) or Bosentan (10(-5) M) was initiated 10 minutes before onset of ischemia. Moderate or severe ischemia was induced by reduction (52-61% and 70-82%, respectively) in perfusate flow. Thirty minutes of ischemia/hypoxia (5% O2) was followed by 30 minutes of reperfusion/re-oxygenation. Both moderate and severe ischemia increased ANP release. BQ-123 and Bosentan did not affect basal or ischemia-induced ANP release. Exogenous ET-1 perfusion induced a late increase in ANP release (P < 0.01) that did not exceed the increase in ANP release associated with equivalent direct flow reduction. Hypoxia induced an 8-fold increase in ANP release rate. The ANP release rate returned toward basal levels after re-oxygenation. Bosentan, but not BQ-123, significantly attenuated (P < 0.01) hypoxia-induced ANP release. In conclusion, in this system, ANP release is stimulated by moderate (or severe) ischemia and severe hypoxia independent of change in atrial distension; endogenous ET does not mediate basal and ischemia-induced ANP release; and hypoxia-induced ANP release is partially modulated via interaction with endogenous ET.

N-terminal pro-atrial natriuretic peptide as a biochemical marker of long-term interventional success after radiofrequency catheter ablation of paroxysmal supraventricular tachyarrhythmias

Radiofrequency (RF) catheter ablation has been shown to be highly effective in the treatment of supraventricular tachycardias. Atrial natriuretic peptide (ANP) and brain natriuretic peptide (B-type natriuretic peptide; BNP) are secreted by the heart mainly in response to myocardial stretch induced by volume load. The aim of the present study was to determine the time course of the N-terminal prohormone forms of ANP (NT-proANP) and BNP (NT-proBNP) in patients undergoing radiofrequency (RF) catheter ablation for paroxysmal supraventricular tachycardias.

Serial blood samples were taken from 13 patients with symptomatic paroxysmal supraventricular tachycardias undergoing RF ablation and from 13 age- and gender-matched healthy controls. Blood was taken before ablation (day 0, baseline), and at day one and day 120 after ablation. Levels of NT-proANP were significantly higher before RF ablation (4862 ± 726 pmol/l) as compared to day one (2021 ± 220 pmol/l) and day 120 after RF ablation (2470 ± 349 pmol/l) (with p < 0.01 on day one and p < 0.05 on day 120; n = 13). The size of the left atrium decreased from 41.0 ± 5.5 mm before ablation to 34.9 ± 5.9 mm (n = 13; p < 0.05) on day 120 as measured by M-mode echocardiography. Levels of NT-proBNP showed comparable values before and on day one and day 120 after ablation and were not significantly elevated as compared to healthy controls.

NT-proANP levels are increased in patients presenting with paroxysmal supraventricular tachycardias and decrease one day after radiofrequency catheter ablation, possibly reflecting a transient reduction of ANP secretion from injured myocardial cells. Lower NT-proANP levels in the long-term time course may result from reduction of atrial volume load and reconstitution of atrial architecture after successful treatment of supraventricular tachycardias. NT-proANP may serve as a useful laboratory marker to describe the long-term interventional success after RF ablation.

Gene expression of the natriuretic peptide system in atrial tissue of patients with paroxysmal and persistent atrial fibrillation

INTRODUCTION

Circulating cardiac natriuretic peptides play an important role in maintaining volume homeostasis, especially during conditions affecting hemodynamics. During atrial fibrillation (AF), levels of plasma atrial natriuretic peptide (ANP) becomes elevated. The aim of this study was to gather information about gene expression of the natriuretic peptide system on the atrial level in patients with AF.

METHODS AND RESULTS

Right atrial appendages of 36 patients with either paroxysmal or persistent AF were compared with 36 case matched controls in sinus rhythm for mRNA expression of pro- atrial natriuretic peptide (pro-ANP), pro-brain natriuretic peptide (pro-BNP), and their natriuretic peptide receptor type-A (NPR-A). We investigated patients without (n = 36) and with (n = 36) valvular disease. Persistent AF was associated with higher mRNA expression of pro-BNP (+66%, P = 0.04, in patients without valvular disease, and +69%, P < 0.01, in patients with valvular disease) and lower mRNA expression of NPR-A (-58%, P = 0.02, in patients without valvular disease, and -62 %, P < 0.01, in patients with valvular disease). The mRNA content of pro-ANP was only increased in patients with valvular disease (+12%, P = 0.03). No changes were observed in patients with paroxysmal AF.

CONCLUSION

This study demonstrates that persistent, but not paroxysmal, AF induces alterations in gene expression of pro-BNP and NPR-A on the atrial level. Although AF generally is associated with an increase of plasma ANP level, a change in mRNA content of pro-ANP is only observed in the presence of concomitant valvular disease and is of minor magnitude.

Plasma concentration of atrial natriuretic peptide in spontaneous atrioventricular re-entrant tachycardias of childhood

Plasma atrial natriuretic peptide was measured in 13 children between the ages of 1 week and 2 years 9 months during atrioventricular re-entrant tachycardia and 15 minutes after the restoration of sinus rhythm. There was a significant decline in atrial natriuretic peptide during sinus rhythm. Plasma concentrations of the peptide were significantly higher during tachycardia in seven infants under 1 year than in the six older children. The heart rates and the duration of tachycardia were not significantly different in the two age groups. Cardiac failure was present in five of seven children under 18 weeks of age during tachycardia but in none of the older children. The plasma concentration of atrial natriuretic peptide did not significantly correlate with duration of tachycardia or heart rate. If tachycardia occurs in young infants the low functional reserve capacity of the developing heart leads to cardiac failure more frequently and it is likely that this was the cause of the significantly higher plasma concentration of atrial natriuretic peptide in the younger children.

Cardiovascular protective properties of indapamide

Although indapamide has been used for many years as a first-line treatment of hypertension, it is only recently that some of its activities on the changes of the cardiovascular system, brought on by age and high blood pressure, have been studied. Indapamide appears to reduce blood pressure by a combined diuretic and direct vascular activity reducing vascular reactivity and total peripheral resistance. In addition, it has discrete effects on a number of interrelated systems that may protect the cardiovascular system. Indapamide reduces intracellular calcium levels, maintains magnesium ions, but reduces phosphate ions that may be involved in arterial rigidity. Circulating catecholamines remain unchanged but there is a reduction in normetanephrine, suggesting a reduction in sympathetic tone. It stimulates prostacyclin synthesis, increases levels of circulating prostacyclin, reduces platelet aggregation and stimulates the vasodilation elicited by endothelium-derived relaxing factor in the presence of bradykinin. In addition, it inhibits the formation of the vasoconstrictor prostanoid, thromboxane A2. The free radical scavenging activity of indapamide could also protect the vascular smooth muscle from the reperfusion injury of cerebral and myocardial ischemia. Indapamide induces a reduction in cerebral ischemia after carotid ligation. Unlike some other antihypertensives, it does not upset the high-density/low-density lipoprotein-cholesterol balance, reducing the possible risk of atherosclerosis. Moreover, the combination of binding to elastin and reduction in uptake of calcium and phosphate into the smooth muscle could be a mechanism for reducing arterial rigidity seen in the elderly and hypertensive patient. In hypertensive patients, these properties induce an improvement in arterial compliance, and in the long term a reduction in left ventricular hypertrophy. These pharmacologic and clinical results, together with a good antihypertensive efficacy and acceptability, suggest that indapamide may be a preferential agent in the long-term cardiovascular protection of the hypertensive patient.

Atrial natriuretic peptide during different pacing modes in a comparison with hemodynamic changes

The study investigates the response of atrial natriuretic peptide (ANP) to different cardiac pacing modes in comparison with hemodynamic changes. Ten patients underwent Swan-Ganz catheterization during pacemaker implant. Atrioventricular and ventricular pacing were performed consecutively at three pacing rate levels (80, 100, and 110 ppm). Blood samples were taken from the pulmonary artery for ANP determination, both basally and at the end of each pacing period. Concomitantly, mean pulmonary capillary wedge pressure (PCWP) and mean pulmonary artery pressure (PAP) were measured. Cardiac output (CO) was determined by thermodilution both basally and during the 110 ppm steps. During atrioventricular pacing, whereas no significant changes were observed for ANP, PCWP and PAP, CO increased significantly (P less than 0.0005). At the beginning of ventricular pacing hemodynamic parameters and ANP levels were comparable with those of baseline conditions. During subsequent ventricular pacing PCWP and ANP increased significantly at the 110 ppm rate step (P less than 0.05). PAP did not change significantly, whereas CO decreased in all cases (P less than 0.01). A positive correlation was observed between ANP and PCWP during ventricular (P less than 0.001), but not atrioventricular pacing. The results, while confirming the hemodynamic advantages of atrioventricular pacing, point to a major stimulation of ANP secretion during ventricular pacing. This fact, together with the observed drop in CO and the correlation between ANP and PCWP, suggest that the increase of ANP in ventricular pacing may be the expression of a compensatory mechanism to the hemodynamic disadvantages of atrioventricular asynchrony.

The effect of tachycardia on right atrial dynamics and plasma atrial natriuretic factor in anaesthetized rabbits

1. The effect of tachycardia on right atrial pressure (RAP) and dimensions (RAD) and plasma immunoreactive atrial natriuretic factor (IR-ANF) was examined in anaesthetized rabbits before and after the administration of atenolol. 2. Small increases in plasma IR-ANF occurred during pacing at 6 Hz and after the administration of atenolol (0.4 mg kg-1). A significantly greater increase in IR-ANF occurred during pacing in the presence of atenolol. 3. Despite a significant rise in mean RAP, systolic RAD (SRAD) and diastolic RAD (DRAD) did not change during tachycardia. Systolic RAD increased after the administration of atenolol while both SRAD and DRAD increased during pacing in the presence of atenolol. 4. Systolic right atrial wall stress (SRAS) increased during tachycardia, did not change after the administration of atenolol, and increased during pacing in the presence of atenolol. Minute SRAS followed a similar pattern of changes except that it decreased after atenolol. 5. Diastolic right atrial wall stress (DRAS) did not change during tachycardia, and increased both after atenolol and after pacing in the presence of atenolol. Tachycardia led to an increase in minute DRAS; a significantly greater increase in minute DRAS occurred during tachycardia in the presence of atenolol. 6. The absence of alterations in RAD during tachycardia suggests that the release of ANF in response to tachycardia is not due to simple mechanical stretch of the atria. Both systolic and diastolic atrial wall stress may be determinants of ANF release: the influence of systolic factors appears to predominate during tachycardia while diastolic factors appear to be the major determinants of the effects of atenolol.

Concentrations of plasma atrial natriuretic factor during and after reversion of ventricular tachycardia

Plasma concentrations of immunoreactive atrial natriuretic factor were considerably increased (mean 745 (376) pg/ml) in 15 patients during spontaneous ventricular tachycardia. There was no significant relation, however, between concentrations of plasma atrial natriuretic factor and systolic arterial blood pressure during tachycardia. Samples taken 30 minutes and 24 hours after reversion of ventricular tachycardia to sinus rhythm showed that, although plasma concentrations of atrial natriuretic factor had fallen significantly, they were still raised after 24 hours. Raised concentrations of atrial natriuretic factor during ventricular tachycardia did not seem to contribute significantly to the hypotension that is often associated with the arrhythmia.