The effects of acute blood loss on blood pressure recovery from the Valsalva maneuver.

Human baroreflex regulation plays an important role in stabilising blood pressure. Though we have several indices to quantify cardiovagal responses, sympathetic baroreflex gain remains difficult to assess. We investigated how the recently validated pressure recovery time (PRT) and sympathetic baroreflex gain (SBRS) derived from the Valsalva maneuver was influenced by acute blood loss. 26 healthy blood donors were included in the study (age 35 ± 15 years; 20 men). SBRS was derived from the blood pressure drop (SAP delta) and pressure recovery time during the Valsalva maneuver. Besides we calculated cardiovagal baroreflex parameters, the Valsalva ratio (VR) and a simplified baroreflex gain (VBRS). We compared these parameters before and after the withdrawal of 350-400 ml blood. The baseline systolic blood pressure was the same before and after blood donation (123 ± 17 vs 126 ± 23 mm Hg, NS). The minimum systolic pressure (SAP min) during phase III was significantly lower, and the SAP delta significantly greater after blood withdrawal (SAP min 83 ± 24 mm Hg vs 69 ± 27 mm Hg, p<0.001; SAP delta 41 ± 15 mm Hg vs 57 ± 16 mm Hg, p<0.001). PRT increased significantly (from 2.0 to 3.6s, p<0.006). SBRS did not change between the study conditions (24 ± 12 mm Hg/s vs 22 ± 10 mm Hg/s, NS), nor did the VR and the VBRS: In conclusion, after the acute loss of approximately 350-400 ml blood there was a greater blood pressure drop in phase II and III and a slower blood pressure recovery in phase IV of the Valsalva maneuver that resulted in an unchanged SBRS.

Bi-atrial and right atrial activation times help to differentiate focal from macroreentrant right atrial tachycardias.

OBJECTIVE: The objective was to study atrial activation intervals and their relation to the tachycardia cycle length (TCL) as electrophysiologic parameters differentiating focal (FAT) from macroreentrant atrial tachycardias (MRAT) originating in the right atrium. METHODS: In 21 patients (8 men) with 30 successfully ablated right atrial tachycardias (15 focal) the endocardial activity during tachycardia was registered using multipolar catheters in the right atrium and the coronary sinus. Using this catheter configuration we measured the tachycardia cycle length (TCL), biatrial activation (BAA), right atrial activation (RAA), left atrial activation (LAA), as well as the proportion of those intervals to TCL. In 14 patients, the measurements were repeated in sinus rhythm as well. The diagnostic accuracy of the ratio of BAA to TCL was assessed. RESULTS: TCL was longer, but all other intervals and ratios were significantly shorter in FAT compared to MRAT (P < 0.05 for all parameters, except for LAA - P = NS). During sinus rhythm, patients with MRAT had prolonged RAA (P = 0.003), but not BAA and LAA (P = NS), compared to patients with FAT. A discriminating value of 40% for the ratio of BAA to TCL, compared to 50% and 30%, was found to have the best sensitivity, specificity, positive and negative predictive values for MRAT, as well as for FAT. CONCLUSIONS: BAA, RAA, LAA and their relation to the TCL are significantly shorter in FATs compared to MRATs arising from the right atrium. The ratio of BAA to TCL obtained using a simple 2-catheter configuration, allows a rapid and reliable differentiation between FAT and MRAT.

[Treatment of arrhythmias associated with congenital heart disease using transcatheter ablation]. / Veleszületett szívbetegséghez társuló ritmuszavarok katéterablatiós kezelése.

UNLABELLED: Rhythm disturbances are common long after surgical repair of congenital heart disease. These arrhythmias caused by the progression of the disease itself, however, a significant proportion is a result of the presence of surgical scar. Although interventional electrophysiology procedures are complex and encounter difficulties, pharmacological therapy is often very disappointing. AIM AND METHODS: In the present study we aimed to describe our experience obtained between 2004 and 2006 in patients undergoing transcatheter ablation long after surgery for congenital heart disease. RESULTS: During this period 26 patients underwent catheter ablation. The procedure was successful in 24 out of the 26 patients (92%). Three patients required redo ablations due to arrhythmia recurrences (11%). There were no major complications related to the intervention. In four patients minor complications occurred (small hematomas). CONCLUSIONS: Our descriptive data indicate that transcatheter ablation for arrhythmias after surgery for congenital heart disease is a effective safe and more importantly curative procedure. It is associated with reasonable success rate, low complication rate, but slightly higher recurrence rate as compared to the classical electrophysiological interventions.

Mid-term echocardiographic follow up of left ventricular function with permanent right ventricular pacing in pediatric patients with and without structural heart disease.

BACKGROUND: Chronic right ventricular apical pacing may have detrimental effect on left ventricular function and may promote to heart failure in adult patients with left ventricular dysfunction. METHODS: A group of 99 pediatric patients with previously implanted pacemaker was studied retrospectively. Forty-three patients (21 males) had isolated congenital complete or advanced atrioventricular block. The remaining 56 patients (34 males) had pacing indication in the presence of structural heart disease. Thirty-two of them (21 males) had isolated structural heart disease and the remaining 24 (13 males) had complex congenital heart disease. Patients were followed up for an average of 53 +/- 41.4 months with 12-lead electrocardiogram and transthoracic echocardiography. Left ventricular shortening fraction was used as a marker of ventricular function. QRS duration was assessed using leads V5 or II on standard 12-lead electrocardiogram. RESULTS: Left ventricular shortening fraction did not change significantly after pacemaker implantation compared to preimplant values overall and in subgroups. In patients with complex congenital heart malformations shortening fraction decreased significantly during the follow up period. (0.45 +/- 0.07 vs 0.35 +/- 0.06, p = 0.015). The correlation between the change in left ventricular shortening fraction and the mean increase of paced QRS duration was not significant. Six patients developed dilated cardiomyopathy, which was diagnosed 2 months to 9 years after pacemaker implantation. CONCLUSION: Chronic right ventricular pacing in pediatric patients with or without structural heart disease does not necessarily result in decline of left ventricular function. In patients with complex congenital heart malformations left ventricular shortening fraction shows significant decrease.

[Valsalva maneuver, Müller maneuver: hemodynamic and reflex mechanisms, relevance]. / Valsalva-manover, Müller-manover: Keringési és reflexmechanizmusok, relevanciák.

The time honored ancient reflex tests, the Valsalva and Müller maneuvers are still popular in the everyday clinical practice. These maneuvers are capable of imitating both trivial situations and significant pathological conditions. The Valsalva maneuver is still frequently used for the assessment of autonomic neuropathy. Addition of continuous noninvasive blood pressure monitoring allows assessment of both cardiac vagal and sympathetic driven peripheral vasomotor responses. The Müller maneuver has recently gained renewed popularity in simulating episodes of obstructive sleep apnea (OSA). Continuous monitoring of arterial pressure and muscle sympathetic nerve activity (MSNA) casts light on the close relationship between OSA and circulatory abnormalities.

Evolution of left ventricular function in paediatric patients with permanent right ventricular pacing for isolated congenital heart block: a medium term follow-up.

AIMS: We aimed to assess the evolution of left ventricular (LV) systolic function in children with right ventricular apical (RVA) pacing for isolated congenital heart block (ICHB) and to identify possible predictors of LV function deterioration. Right ventricular apical pacing can be detrimental to LV function in a significant number of adults. Effects in children are still controversial. METHODS AND RESULTS: Left ventricular shortening fraction (LV SF) and QRS duration were retrospectively assessed in 45 children with RVA pacing for ICHB: before pacemaker (PM) implantation, immediately after and then regularly during a follow-up of 58.69 +/- 45.23 months. Patients were categorized as stable or deteriorators according to an arbitrarily chosen cut-off point of > or =7% decrease in LV SF. Lupus status was unknown. Overall LV SF did not change significantly (41.42% +/- 8.21 before pacing, 39.77% +/- 7.03 immediately after PM implant, 37.43% +/- 9.91 with chronic pacing, P = NS). Deteriorators (n = 13) had significantly higher baseline heart rate (57.5 +/- 8.7 vs. 46.9 +/- 10.5 bpm, P < 0.05) and baseline LV SF (46.17 +/- 8.13 vs. 38.4 +/- 6.4%; P < 0.05), a significantly higher proportion of them being implanted before 2 years of age: 8 of 13 (61.5%) vs. 5 of 25 (20%) in the stable group (P < 0.05). Deteriorators had a higher incidence of an initial epicardial lead and narrower native QRS. CONCLUSION: Permanent RVA pacing for ICHB does not necessarily affect LV function in children. The risk of deterioration of LV function seems to be higher in children with higher baseline heart rate and better baseline LV SF, especially with pacing at a younger age, a narrower native QRS and RVA epicardial pacing site.

Ice mapping during tachycardia in close proximity to the AV node is safe and offers advantages for transcatheter ablation procedures.

BACKGROUND: Ablation during ongoing orthodromic reentry tachycardia (AVRT) and atrioventricular nodal reentry tachycardia (AVNRT) is not recommended using radiofrequency energy when the arrhythmia substrate is located in close proximity to the atrioventricular (AV) node due to a significant risk for inadvertent AV block. The aim of the study is to test the feasibility of ice mapping during tachycardias involving arrhythmia substrate located in close proximity to the AV node. METHODS: This was a single-centre, prospective, randomized study. A total of 65 patients was screened and 30 patients with supraventricular arrhythmias were assigned either to a cryo or RF energy group after diagnosis of AVNRT (17 pts) or AVRT (13 pts) with an anteroseptal accessory pathway. RF ablation was performed using standard ablation techniques. In the cryo group, ice mapping was performed during tachycardia with cooling of the catheter tip temperature to a maximum of -40 degrees C. Ablation was performed only if ice mapping terminated the tachycardia without prolongation of the AV conduction. RESULTS: The overall acute success rate was 84%, and was not different in the cryo and RF groups (85% vs. 82.4%, P = 0.43). Both fluoroscopy and the procedure times were comparable. There was a marked reduction in the mean number of applications in the cryo group [2 (1-6) vs. 7 (1-41), P = 0.002]. In one patient ablation was not attempted in the cryo group because of AV prolongation, and in two patients temporary second-degree AV block was observed in the RF group. After 12 months follow-up the long-term success rate was similar between the two groups. CONCLUSIONS: (I) Ice mapping is a feasible method to determine the exact location of accessory pathways and of the slow pathway during tachycardia. (2) Ice mapping performed during tachycardia causes less ablation lesions without increasing the procedure and fluoroscopy times.

Unusual Wenckebach phenomenon due to an atrial tachycardia arising from the apex of Koch's triangle in the presence of dual AV nodal physiology.

A case of a patient with narrow QRS tachycardia and without structural heart disease is presented. The electrophysiologic study revealed an atrial tachycardia in the presence of dual atrioventricular (AV) nodal physiology and AV block at suprahisian level, the latter two leading to an unusual Wenckebach periodicity. The entire septal area was mapped as was the coronary sinus (CS) os and the earliest atrial activation was found at the apex of Koch's triangle in close vicinity to the His bundle (HB). Cryomapping at that point reproducibly terminated the tachycardia without impairing AV conduction. Cryoablation rendered the tachycardia non-inducible. Discontinuous AV conduction persisted but AV nodal reentrant tachycardia (AVNRT) was not inducible. Six months later the patient is arrhythmia-free.

A simple algorithm for defining the mechanism and the chamber of origin in atrial tachycardias.

INTRODUCTION: Although macroreentrant atrial tachycardia (MRAT) and focal atrial tachycardia (FAT) can be successfully cured by catheter ablation, the proper diagnosis and treatment of these arrhythmias can still be challenging. AIM: The objective of this study is to develop an algorithm allowing rapid diagnosis of the mechanism and the chamber of origin of atrial tachycardia based on intracardiac catheter recordings from the right atrium and the coronary sinus (CS). METHODS: A 2-stepped algorithm was designed: (1) The time of biatrial activation expressed as a percentage of the tachycardia cycle length served to discriminate FAT from MRAT. (2) In FAT, the direction of activation of the CS catheter and the earliest atrial activation were used to define the chamber of origin. In MRAT, the time of right atrium activation was determined or entrainment was used at different sites. Thirty-two intracardiac recordings were reviewed off-line after the algorithm by 4 electrophysiologists blinded to the mechanism and the chamber of origin. The results of their analysis were compared with the intraoperative diagnosis. RESULTS: The algorithm correctly identified 11 (100%) of 11 FATs and 19 (90.4%) of 21 MRATs. The site of origin was correctly identified in 8 (72.7%) of 11 FATs and in 20 of 21 (95.2%) MRATs. The site of origin was misidentified in 3 FATs, all arising from the CS ostium. CONCLUSIONS: This algorithm allows rapid discrimination between FAT and MRAT. The chamber of origin is detected with a high accuracy in MRAT. However, the earliest atrial activation taken as an isolated event is not a good predictor for the chamber of origin in FAT arising from the ostium of the CS.

Right diaphragmatic paralysis following endocardial cryothermal ablation of inappropriate sinus tachycardia.

Inappropriate sinus tachycardia (IST) is a rare disorder amenable to catheter ablation when refractory to medical therapy. Radiofrequency (RF) catheter modification/ablation of the sinus node (SN) is the usual approach, although it can be complicated by right phrenic nerve paralysis. We describe a patient with IST, who had symptomatic recurrences despite previous acutely successful RF SN modifications, including the use of electroanatomical mapping/navigation system. We decided to try transvenous cryothermal modification of the SN. We used 2 min applications at -85 degrees C at sites of the earliest atrial activation guided by activation mapping during isoprenaline infusion. Every application was preceded by high output stimulation to reveal phrenic nerve proximity. During the last application, heart rate slowly and persistently fell below 85 bpm despite isoprenaline infusion, but right diaphragmatic paralysis developed. At 6 months follow-up, the patient was asymptomatic and the diaphragmatic paralysis had partially resolved. This is the first report, we believe, of successful SN modification for IST by endocardial cryoablation, although this case also demonstrates the considerable risk of right phrenic nerve paralysis even with this ablation energy.

[Intracardiac echocardiography in clinical cardiac electrophysiology: review and first Hungarian experience]. / Az intracardialis ultrahangvizsgálat használata a szív elektrofiziológiában: attekintés az elso hazai vizsgálatok kapcsán.

During the last two decades revolutionary diagnostic and therapeutic changes were implemented in the management of patients with arrhythmias. Since the arrhythmia substrate is frequently associated with certain anatomical structures or morphological variants, improved imaging has increasing role in the improvement of these treatments. Furthermore, novel catheter ablation approaches require catheter placement to sites, which may be associated with increased complication risk. Therefore imaging has a crucial role both in guiding and improving safety of electrophysiology procedures. Recently, intracardiac echocardiography became available providing excellent accuracy in direct visualization of anatomical landmarks. Intracardiac echocardiography is therefore a potentially useful tool for guiding electrophysiology procedures. The first two Hungarian cases with intracardiac echocardiography are presented with a broad background in this comprehensive review.

Preventing complicated transseptal puncture with intracardiac echocardiography: case report.

BACKGROUND: Recently, intracardiac echocardiography emerged as a useful tool in the electrophysiology laboratories for guiding transseptal left heart catheterizations, for avoiding thromboembolic and mechanical complications and assessing the ablation lesions characteristics. Although the value of ICE is well known, it is not a universal tool for achieving uncomplicated access to the left atrium. We present a case in which ICE led to interruption of a transseptal procedure because several risk factors for mechanical complications were revealed. CASE PRESENTATION: A case of a patient with paroxysmal atrial fibrillation and atrial flutter, and distorted intracardiac anatomy is presented. Intracardiac echocardiography showed a small oval fossa abouting to an enlarged aorta anteriorly. A very small distance from the interatrial septum to the left atrial free wall was seen. The latter two conditions were predisposing to a complicated transseptal puncture. According to fluoroscopy the transseptal needle had a correct position, but the intracardiac echo image showed that it was actually pointing towards the aortic root and most importantly, that it was virtually impossible to stabilize it in the fossa itself. Based on intracardiac echo findings a decision was made to limit the procedure only to ablation of the cavotricuspid isthmus and not to proceed further so as to avoid complications. CONCLUSION: This case report illustrates the usefulness of the intracardiac echocardiography in preventing serious or even fatal complications in transseptal procedures when the cardiac anatomy is unusual or distorted. It also helps to understand the possible mechanisms of mechanical complications in cases where fluoroscopic images are apparently normal.

Human autonomic responses to blood donation.

In order to characterize autonomic responses to acute volume loss, supine ECG, blood pressure (BP) and uncalibrated breathing signal (UBS) recordings were taken before and after blood donation in 48 healthy volunteers. Time and frequency domain parameters of RR interval (RRI), BP and UBS variability were determined. Baroreflex gain was calculated by the technique of the spontaneous sequences and cross-spectral analysis. The systolic (SAP), diastolic (DAP) and mean BP (MAP) increased after the blood withdrawal. The central frequency of breathing and mean heart rate did not change. RRI variability increased in low frequency band (LF), tended to decrease in high frequency band (HF). Systolic BP variability increased in both frequency bands, but was statistically significant only in the high frequency band. Diastolic BP power increased in both frequencies. From the different baroreflex gain estimates, up sequence BRS and HF alpha index decreased significantly. The phase angle between RRI and systolic blood pressure powers in LF band did not change (-58 +/- 24 degrees and -54 +/- 26 degrees ). In the high frequency range, the phase became more negative (-1 +/- 29 degrees and -17 +/- 32 degrees, p = 0.001). The withdrawal of 350-400 ml blood in 5 min resulted in sympathetic activation, which was reflected in increased systolic, diastolic and mean BP. The increased BP oscillation was a sensitive marker of the minor volume depletion. This was coupled by increased RRI oscillation via baroreflex mechanisms in the LF band. Changes in the RRI and BP oscillations in the HF band showed no similar coupling. That points to the fact that RRI oscillations in this band should not be explained entirely by baroreflex mechanisms. Vagal withdrawal was reflected in decreased root mean square of successive differences (RMSSD), decreased HF RRI power and decreased up sequence BRS.

Cardiovascular autonomic dysfunction in primary Sjögren's syndrome.

OBJECTIVE: To assess the occurrence and clinical significance of a cardiovascular autonomic nervous system dysfunction in primary Sjögren's syndrome (pSS). METHODS: Fifty-one pSS patients participated in this case-control study. Heart rate and blood pressure variability measurements, spontaneous baroreflex sensitivity examinations and cardiovascular reflex tests were performed. RESULTS: The results of the heart rate and blood pressure variability measurements and also the baroreflex sensitivity parameters of the pSS patients peaked in the lowest percentile ranges of a database on 559 healthy control subjects (P < 0.05). In three of the five cardiovascular reflex tests, the frequencies of abnormal results were significantly higher among the patients than among the controls (P < 0.05), and the median autonomic neuropathy score was also elevated (3 vs 0 in the controls; P < 0.0001). CONCLUSION: Signs of an autonomic nervous system dysfunction involving the cardiovascular system can be discerned in the majority of pSS patients.

Oesophageal acid stimulation in humans: does it alter baroreflex function?

The aim of this study was to investigate if oesophagel acid stimulation (Bernstein test) had an influence on heart rate and blood prsure variability and baroreflex gain. We compared the cardiovascular responses in 10 patients with established gastro-esophageal reflux disease (Group 1) and 10 control subjects (Group 2) during esophageal saline and 0.1 mol/l hydrochloric acid instillation. Indices of heart rate and blood pressure variability and baroreflex gain (derived from linear spontaneous sequences and cross spectral analysis) were calculated. In Group 1 the standard deviation of RR intervals (SDRR: 46 ms vs 51 ms, p=0.030) and the root mean square of successive differences (RMSSD: 24 ms vs. 26 ms p=0.027) were significantly lower during acid infusions, than during saline. We found no significant difference in minimum, maximum and mean RR intervals and systolic blood pressures and in the percentage of RR intervals, which differed from adjacent cycles by more than 50 ms (PNN50). The power spectra of RR intervals in the high frequency band tended to be lower during acid infusion (p=0.055). There was no significant difference in blood pressure spectra, neither in low nor in high frequency band. In Group 2 there was no significant difference between any parameters measured during acid and saline. The baroreflex gain was not changed during the studied conditions in any group. Neither increased vagal tone, nor increased vagal variability occurred and the baroreflex gain was not altered during oesophageal acid simulation.

Measures of cardiovascular autonomic regulation derived from spontaneous methods and the Valsalva maneuver.

The response of heart rate to a given change of systolic blood pressure is a fundamental characteristic of the cardiovascular system. The assessment of baroreflex gain (BRS) as an index of baroreflex function is based on the quantification of RR interval changes related to blood pressure changes. The spontaneous sequence and cross spectral methods describe baroreflex gain derived from spontaneous fluctuations of these parameters, yielding the up sequence and down sequence BRS and the alfa index. Phase IV of the Valsalva maneuver is also used to calculate cardiac vagal baroreflex gain. In this study, we compared the two spontaneous methods and the Valsalva maneuver in assessing baroreflex gain in 56 healthy volunteers. The BRS values calculated from different methods were as follows: up sequence BRS 12 +/- 8.6 ms/mm Hg, down sequence BRS 10 +/- 6.1 ms/mm Hg, low frequency alfa index 12.1 +/- 8.2 ms/mm Hg, Valsalva BRS 9.7 +/- 7.2 ms/mm Hg. We found close relationship between baroreflex gain derived from up and down sequences (R = 0.91, p < 0.001), down sequence BRS and low frequency alfa index (R = 0.81, p < 0.001); significant correlation between up sequence BRS and low frequency alfa index (R = 0.65, p < 0.001), the Valsalva-derived BRS and down sequence BRS (R = 0.37, p = 0.043), but no correlation between the Valsalva BRS and up sequence BRS, the Valsalva BRS and low frequency alfa index. BRS values calculated by different methods decreased with increasing age. There was no influence of age on mean arterial blood pressure elevation in late phase II of the Valsalva maneuver, nor any indication that the Valsalva BRS was related to the MAP changes. We concluded that all of these methods are useful in calculating baroreflex gain, but owing to the differences in underlying physiological mechanisms, they are not necessarily in correlation with each other.