Relationship between the electrical (electrocardiographic) and mechanical (echocardiographic) events in Wolff-Parkinson-White syndrome

Iatrogenic cardiomyopathy in patients with manifest right supero-paraseptal accessory pathways

INTRODUCTION

We describe two patients with right supero-paraseptal accessory pathway (SPAP) who developed left ventricular dysfunction associated with an increased degree of ventricular pre-excitation and frequent orthodromic reciprocating tachycardia (ORT) due to worsening atrioventricular (AV) node conduction.

METHODS AND RESULTS

Case 1: 48-year-old female with a history of normally functioning mechanical mitral valve, CABG, and ventricular pre-excitation that worsened after her open heart surgery. She presented with frequent palpitations with documented supraventricular tachycardia (SVT) and found to have a new left ventricular dysfunction with decrease in left ventricular ejection fraction (LVEF) from 55% to 46% with dyssynchrony. An electrophysiological study confirmed a right SPAP and ORT. The pathway was successfully ablated from the antegrade approach after careful mapping. After ablation and 6-month follow up echocardiogram showed improvement of EF to 54% and the LV dyssynchrony resolved. Case 2: 51-year-old male with a history of frequent SVT with recent unsuccessful ablations that resulted in worsening ventricular pre-excitation, more frequent SVT, and new left ventricular dysfunction (LVEF from 60% to 40%). He was started on amiodarone which resulted in significant sinus bradycardia, intermittent ventricular pre-excitation, and first degree AV block with significant increase in ORT events. His electrophysiology study confirmed SPAP which was successfully ablated from the antegrade approach after careful mapping. After 1 month, follow-up echocardiogram showed an improved ejection fraction to 60%.

CONCLUSION

Left ventricular dysfunction due to dyssynchrony and symptomatic frequent ORT of right SPAP can develop in the setting of new iatrogenic diminished AV node conduction. Successful ablation will result in LV function recovery to baseline.

Altered myocardial characteristics of the preexcited segment in Wolff-Parkinson-White syndrome: A pilot study with cardiac magnetic resonance imaging

Purpose

The preexcited myocardium of Wolff-Parkinson-White (WPW) syndrome would have different characteristics from normal myocardium and these findings might be related to persistent left ventricular systolic dysfunction. We evaluated myocardial tissue characteristics at the preexcited segment in adult WPW syndrome patients and their implicated findings.

Methods

For this prospective study, we enrolled 22 adult WPW syndrome patients (16 male, mean 45.4 ± 17.8 years) with echocardiographic findings of regional wall motion abnormality in our electrophysiology clinic. Of these patients, 14 underwent radiofrequency ablation before cardiac magnetic resonance imaging. All patients underwent cardiac magnetic resonance imaging including cine and late gadolinium enhancement. The ventricular morphology, function and myocardial characteristics of the preexcited segment were analyzed.

Results

A relatively high prevalence of late gadolinium enhancement (9/22, 40.9%) was observed exclusively at the basal septum. The septal accessory pathway was significantly more prevalent in patients with late gadolinium enhancement (P = 0.011). The prevalences of regional myocardial wall thinning and regional akinesia were significantly higher (P = 0.001 for both) and left ventricular function was significantly decreased in patients with late gadolinium enhancement (P < 0.001). In addition, there were no significant relationships between radiofrequency ablation and regional akinesia (P > 0.999), regional myocardial wall thinning (P > 0.999), late gadolinium enhancement (P = 0.662) and low ejection fraction (P > 0.999).

Conclusion

Myocardial fibrosis was observed at the preexcited myocardium of adult WPW syndrome patients with septal accessory pathway, which could accompany regional akinesia and regional myocardial wall thinning and might be related to persistent left ventricular systolic dysfunction even after radiofrequency ablation.

Detecting Regional Myocardial Abnormalities in Patients With Wolff-Parkinson-White Syndrome With the Use of ECG-Gated Cardiac MDCT

OBJECTIVE

Myocardial dyskinesia caused by the accessory pathway and related reversible heart failure have been well documented in echocardiographic studies of pediatric patients with Wolff-Parkinson-White (WPW) syndrome. However, the long-term effects of dyskinesia on the myocardium of adult patients have not been studied in depth. The goal of the present study was to evaluate regional myocardial abnormalities on cardiac CT examinations of adult patients with WPW syndrome.

MATERIALS AND METHODS

Of 74 patients with WPW syndrome who underwent cardiac CT from January 2006 through December 2013, 58 patients (mean [± SD] age, 52.2 ± 12.7 years), 36 (62.1%) of whom were men, were included in the study after the presence of combined cardiac disease was excluded. Two observers blindly evaluated myocardial thickness and attenuation on cardiac CT scans. On the basis of CT findings, patients were classified as having either normal or abnormal findings. We compared the two groups for other clinical findings, including observations from ECG, echocardiography, and electrophysiologic study.

RESULTS

Of the 58 patients studied, 16 patients (27.6%) were found to have myocardial abnormalities (i.e., abnormal wall thinning with or without low attenuation). All abnormal findings corresponded with the location of the accessory pathway. Patients with abnormal findings had statistically significantly decreased left ventricular function, compared with patients with normal findings (p < 0.001). The frequency of regional wall motion abnormality was statistically significantly higher in patients with abnormal findings (p = 0.043). However, echocardiography documented structurally normal hearts in all patients.

CONCLUSION

A relatively high frequency (27.6%) of regional myocardial abnormalities was observed on the cardiac CT examinations of adult patients with WPW syndrome. These abnormal findings might reflect the long-term effects of dyskinesia, suggesting irreversible myocardial injury that ultimately causes left ventricular dysfunction.

Left ventricular dysfunction and dilated cardiomyopathy in infants and children with wolff-Parkinson-white syndrome in the absence of tachyarrhythmias

Left ventricular (LV) dysfunction and dilated cardiomyopathy (DCM) are rarely attributable to sustained or incessant tachyarrhythmias in infants and children with Wolff-Parkinson-White (WPW) syndrome. However, several recent reports suggested that significant LV dysfunction may develop in WPW syndrome in the absence of tachyarrhythmias. It is assumed that an asynchronous ventricular activation over the accessory pathway, especially right-sided, induces septal wall motion abnormalities, ventricular remodeling and ventricular dysfunction. The prognosis of DCM associated with asymptomatic WPW is excellent. Loss of ventricular pre-excitation results in mechanical resynchronization and reverse remodeling where LV function recovers completely. The reversible nature of LV dysfunction after loss of ventricular pre-excitation supports the causal relationship between LV dysfunction and ventricular pre-excitation. This review summarizes recent clinical and electrophysiological evidence for development of LV dysfunction or DCM in asymptomatic WPW syndrome, and discusses the underlying pathophysiological mechanism.

Septal dyskinesia and global left ventricular dysfunction in pediatric Wolff-Parkinson-White syndrome with septal accessory pathway

INTRODUCTION

Echocardiographic studies have shown that some patients with Wolff-Parkinson-White (WPW) syndrome have myocardial dyskinesia in the segments precociously activated by an accessory pathway (AP). The aim of the present study was to determine the extent to which the AP contributes to global left ventricular (LV) dysfunction.

METHODS

Electrophysiological and echocardiographic data from 62 children with WPW (age at diagnosis = 5.9 +/- 4.2 years) were retrospectively analyzed.

RESULTS

The left ventricular ejection fraction (LVEF) of patients with septal APs (53 +/- 11%) was significantly lower than that of patients with right (62 +/- 5%) or left (61 +/- 4%) APs (P = 0.001). Compared to patients with normal septal motion (n = 56), patients with septal dyskinesia (n = 6) had a reduced LVEF (61 +/- 4% and 42 +/- 5%, respectively) and an increased LV end diastolic dimension (P < 0.001 for both comparisons). Multivariate analysis identified septal dyskinesia as the only significant risk factor for reduced LVEF. All 6 patients with septal dyskinesia had right septal APs, and a preexcited QRS duration that was longer than that of patients with normal septal motion (140 +/- 18 ms and 113 +/- 32 ms, respectively; P = 0.045). After RFA there were improvements in both intraventricular dyssynchrony (septal-to-posterior wall motion delay, from 154 +/- 91 ms to 33 +/- 17 ms) and interventricular septal thinning (from 3.0 +/- 0.5 mm to 5.3 +/- 2.6 mm), and a significant increase in LVEF (from 42 +/- 5% to 67 +/- 8%; P = 0.001).

CONCLUSION

The dyskinetic segment activated by a right septal AP in WPW syndrome may lead to ventricular dilation and dysfunction. RFA produced mechanical resynchronization, reverse remodeling, and improvements in LV function.

Segmental dyskinesia in Wolff–Parkinson–White syndrome: A possible cause of dilatative cardiomyopathy

Wolff-Parkinson-White (WPW) is a syndrome characterized by the presence of an accessory pathway that skipping A-V node may lead the electrical stimulus from the atrium directly to the ventricle. Some studies reported the finding of myocardial dyskinesia in the segments precociously activated by the accessory pathway, at echocardiogram and at nuclear cardiac study. Soria et al. reported, in 1985, an increased incidence of dilative cardiomyopathy in patients with WPW. The pathophysiological pathway that leads to ventricular dilation may be due to the increase of end-diastolic pressure secondary to a tachycardia-induced cardiomyopathy. Tachycardia-induced cardiomyopathy is usually secondary to frequent and prolonged tachycardia episodes. In this paper we report the cases of three patients affected by WPW who developed dilative cardiomyopathy during the follow-up. Particularly dyskinetic segments, working such as a functional aneurysm, could induce deep modifications of intraventricular haemodynamics, leading to remodelling and progressive ventricular dilation. This hypothesis could have important empirical consequences because it could imply the necessity of a precocious ablative therapy in this kind of patients.

Live Three-Dimensional Echocardiographic Assessment of Mitral Stenosis

In the present study, we describe our experience in using live three-dimensional transthoracic echocardiography in the assessment of mitral stenosis.

Ventricular excitation maps using tissue Doppler acceleration imaging: potential clinical application

OBJECTIVES

The purpose of this study is to validate the use of tissue Doppler acceleration imaging (TDAI) for evaluation of the onset of ventricular contraction in humans.

BACKGROUND

Tissue Doppler acceleration imaging can display the distribution, direction and value of ventricular acceleration responses to myocardial contraction and electrical excitation.

METHODS

Twenty normal volunteers underwent TDAI testing to determine the normal onset of ventricular acceleration. Two patients with paroxysmal supraventricular tachycardia and 30 patients with permanent pacemakers underwent introduction of esophageal and right ventricular pacing electrodes, respectively, and were studied to visualize the onset of pacer-induced ventricular acceleration. Eight patients with dual atrioventricular (AV) node and 20 patients with Wolff-Parkinson-White (WPW) syndrome underwent TDAI testing to localize the abnormal onset of ventricular acceleration, and the results were compared with those of intracardiac electrophysiology (ICEP) tests.

RESULTS

The normal onset and the onset of dual AV node were localized at the upper interventricular septum (IVS) under the right coronary cusp within 25 ms before the beginning of the R wave in the electrocardiogram (ECG). In all patients in the pacing group, the location and timing of the onset conformed to the positions and timing of electrodes (100%). In patients with WPW syndrome, abnormal onset was localized to portions of the ventricular wall other than the upper IVS at the delta wave or within 25 ms after the delta wave in the ECG. The agreement was 90% (18 of 20) between the abnormal onset and the position of the accessory pathways determined by ICEP testing.

CONCLUSIONS

These results suggest that TDAI is a useful noninvasive method that frequently is successful in visualizing the intramural site of origin of ventricular mechanical contraction.

Correlations between the localization of accessory atrioventricular pathway and Doppler indices of left ventricular output and function in patients with Wolff-Parkinson-White syndrome

Left ventricular (LV) output and function was investigated, using pulsed Doppler echocardiography in 52 patients with various localizations of accessory AV pathway (AP) in sinus rhythm and during paroxysm of AV reentrant tachycardia. In patients with sinus rhythm and ventricular preexcitation the most marked decrease in LV output and function (reduced aortic flow peak velocity [PV], mean acceleration [MA], stroke distance [SD], minute distance [MD], and lengthened time to peak velocity [TTP]) was noted in the presence of right parietal AP and less marked changes (decreased MA, lengthened TTP)--in the presence of posteroseptal AP, in comparison with the controls (P less than 0.005). During antidromic tachycardia the pronounced decrease in PV, MA, SD, and MD was noted, especially in patients with left parietal and posteroseptal AP, while in the case of right parietal AP changes in MA and MD were insignificant. During orthodromic tachycardia the decrease in LV function was less marked and no significant differences in the magnitude of LV output and function changes were found in various localizations of AP, except MA, which was more severely decreased in patients with posteroseptal AP. We conclude, that the alterations in Doppler indices of LV output and function are related to the localization of AP during AV reentrant tachycardia and regular sinus rhythm.

Two-dimensional echocardiographic phase analysis. Its potential for noninvasive localization of accessory pathways in patients with Wolff-Parkinson-White syndrome

BACKGROUND

In patients with the preexcitation syndrome who are undergoing transcatheter or surgical ablation, accurate localization of accessory pathways is critical. Because preexcitation is known to alter ventricular activation sequence and result in focal areas with presystolic contraction, we investigated whether phase analysis applied to two-dimensional echocardiographic cine loops objectively identifies these focal areas and can be used to localize ventricular insertion sites of accessory pathways.

METHODS AND RESULTS

We prospectively obtained phase images in 17 patients (11 males; age range, 11-35 years) during minimal preexcitation in normal sinus rhythm and during maximal preexcitation induced by right atrial pacing. A group of 11 normal subjects (six men; age range, 26-37 years) served as controls. Pathway locations predicted from phase imaging were compared with those predicted from routine 12-lead ECGs, from visual inspection of cine loop images, and from catheter-mounted electrode endocardial mapping. Cross-sectional views in a digital cine loop format were mathematically transformed using a first harmonic Fourier algorithm to obtain the corresponding phase images. Phase angle histograms were derived in eight wall segments. Mean and earliest phase angles were derived by computer analysis to quantitate contraction sequence. We found that during right atrial pacing, phase angles in focal areas markedly deviated from normal--mean phase angles from 33 degrees to 164 degrees, and earliest phase angles from 50 degrees to 180 degrees. Accessory pathways could be precisely localized in 53% of the patients by 12-lead ECG, in 59% by visual inspection of cine loop images, in 82% by phase imaging, and in 94% by a combination of the three methods.

CONCLUSIONS

Our results suggest that phase imaging, especially when used in combination with cine loop and 12-lead ECG, can be used to localize ventricular insertion sites of accessory pathways and may be clinically useful as a noninvasive adjunct to endocardial mapping in patients with Wolff-Parkinson-White syndrome.

Characterization of left ventricular mechanical function during arrhythmias by two-dimensional echocardiography. II. Location of the site of onset of premature ventricular systoles

Two-dimensional echocardiography was applied experimentally in a closed chest dog model with intact pericardium to determine the location, magnitude and extent of contractile response during pacing from discrete ventricular sites. Midventricular short-axis tomographic images obtained during regular sinus rhythm and subsequent premature ventricular beats provided comparative measurements of global and segmental systolic changes of cross-sectional luminal areas and myocardial wall thickness. Computer-assisted standardized analysis of segmental systolic fractional area change and wall thickening was used to map left ventricular contraction during normal rhythm and premature beats of 70% coupling interval, induced alternately from anterior and lateral aspects of the mid-left ventricular short-axis cross-sectional plane. A characteristic pattern consisting of early systolic contraction and wall thickening was followed by paradoxical motion and wall thinning in late systole in segments corresponding to the region of direct electrical stimulation. Statistical analysis of segment by segment function indicated a maximal amount of premature beat contractile derangement at the site of the stimuli. Pacing from a right ventricular wall site in the midventricular plane caused a similar premature beat response at the anterior aspect of the interventricular septum. It is concluded that two-dimensional echographic analysis of segmental ventricular function can identify the location of electrical stimuli, and thus might noninvasively characterize regional patterns of contraction associated with ectopic foci during arrhythmias.

Mechanism of abnormal interventricular septal motion during delayed left ventricular activation

To evaluate the mechanism of the abnormal motion of the interventricular septum (IVS) seen echocardiographically in some patients with relatively delayed ventricular activation, we simultaneously recorded high-fidelity left and right ventricular pressures and electrograms and echocardiograms of the IVS in nine open-chest dogs. During sinus rhythm and during left IVS pacing, the IVS was activated from left to right, preejection left ventricular pressure exceeded right ventricular pressure, and IVS motion was normal. During right ventricular pacing from the outflow tract, apex, free wall or right IVS was activated from right to left, right ventricular pressure increased before left ventricular pressure and simultaneously there was an abrupt posterior IVS motion. Simultaneous pacing from the right IVS and left ventricular free wall activated the IVS from right to left and produced a normal transseptal preejection pressure gradient and normal IVS motion. Simultaneous pacing from the left IVS and right ventricular free wall activated the IVS from left to right, and produced abrupt preejection posterior IVS motion coincident with an altered transseptal pressure gradient. During right ventricular pacing, IVS motion after the abrupt preejection posterior movement was variable. Anterior motion was associated with a greater asynchrony of right and left ventricular contraction than was normal posterior motion. We conclude that abrupt preejection posterior IVS motion seen with delayed left ventricular activation from right ventricular pacing is due to passive IVS displacement from an altered transseptal pressure gradient, and subsequent IVS motion depends on the degree of asynchrony between right and left ventricular contraction.

Characterization of left ventricular mechanical function during arrhythmias with two dimensional echocardiography. I. Premature ventricular contractions

Two dimensional echocardiography was applied experimentally in the closed chest dog to quantitate left ventricular function during and immediately after single premature ventricular contractions induced through threshold stimulation at the apex. Coupling intervals were varied over a range from 35 to 85 percent of the R-R interval during normal sinus rhythm (920 to 980 ms). The quality of tomographic echocardiographic images during premature as well as postextrasystolic beats was found to be satisfactory for quantitating short axis section areas at end-diastole and end-systole. A systolic fractional area change was computed from two dimensional echocardiographic measurements to characterize mid ventricular cardiac function, which correlated significantly with peak left ventricular pressure and maximal first derivative of left ventricular pressure (dP/dt). Marked shortening of coupling intervals reduced fractional shortening during premature systole and enhanced the degree of potentiation during the postextrasystolic beat. By contrast, premature beats with relatively long coupling intervals caused less reduction in contraction and only minor postextrasystolic potentiation. Systolic shortening of left ventricular length as well as transverse diameters were studied in a two dimensional echocardiographic long axis cross section. During long coupling intervals contraction was normal except for distinct regional systolic outward "bulging" in the apical region. In contrast, short coupling intervals were associated with a more significant generalized derangement of ventricular wall motion during systole. It is concluded that the two dimensional echocardiographic method can be used to portray and quantitate global as well as regional left ventricular function during disturbances of cardiac rhythm.