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Biomedical subjects

Albert Meijer

Publications and source records attributed to Albert Meijer.

At least 19 recordsLinked to original sources
PubMed2006

Relation of isovolumic times after cardiac resynchronization therapy to improvement in exercise capacity.

Isovolumic times (IVTs) comprise a determinant of exercise capacity in cardiomyopathy. We postulated that an increase in exercise capacity after cardiac resynchronization therapy (CRT) might be related to a more efficient cardiac cycle due to decreasing IVTs and increased filling times. According to standard selection criteria, a CRT device was implanted in 52 patients (37 men; 69 +/- 8 years) with a QRS duration of 174 +/- 30 ms. The etiology was ischemic in 22 and idiopathic in 30 patients. A 6-minute walking test (MWT) and echocardiographic Doppler were performed before and 3 and 6 months after CRT. Timing cycles were obtained with echocardiographic Doppler. An improvement in MWT by >15% (responders) after 6 months of CRT was observed in 46% of patients. The MWT was moderately correlated with baseline time intervals (IVT r = -0.44, filling time r = 0.52), but not to baseline left ventricular ejection fraction (r = -0.06). However, change in the MWT after 3 and 6 months was best related to changes in IVT (r = -0.66 and -0.68, respectively). Receiver-operating characteristic curve analysis of baseline IVT showed that an IVT >29% predicted exercise response with a positive predictive value of 89% and a negative predictive value of 77%. In conclusion, improvement in exercise tolerance after CRT is associated with a decrease in prolonged IVT. Baseline IVT might be used as an adjunctive parameter for selecting symptomatic responders to CRT.

Aged↗
PubMed2006

Paradoxical atrial undersensing: noise rate reversion or amplifier ringing?

Atrial tachy-arrhythmias may give rise to mode switching or noise rate reversion in dual-chamber pacemakers. In case of high amplitude of the atrial electrogram during tachycardia, a paradoxical behavior of atrial sensitivity programming can be observed. Two patients with implanted dual-chamber pacemakers showed intermittent and complete loss of atrial sensing during atrial tachycardia during device programming to a higher atrial sensitivity setting. This phenomenon is caused by amplifier ringing and can be considered as a state of amplifier saturation, which disables atrial sensing in spite of the high amplitude of the atrial signal. In patients with high amplitude of the atrial electrogram during atrial tachycardia, a paradoxical behavior of sensitivity programming resulting in atrial undersensing can be observed.

Adult↗
PubMed2006

Correlation of echo-Doppler optimization of atrioventricular delay in cardiac resynchronization therapy with invasive hemodynamics in patients with heart failure secondary to ischemic or idiopathic dilated cardiomyopathy.

This study investigated the optimal echocardiographic indexes to determine the most hemodynamically appropriate atrioventricular (AV) delay in cardiac resynchronization therapy (CRT) for heart failure. Doppler echocardiographic optimization of AV delay in CRT has not been correlated with invasive hemodynamic indexes. In 30 patients who underwent CRT, invasive left ventricular (LV) pressure measurements with a sensor-tipped pressure guidewire and Doppler echocardiographic examination were performed <24 hours after pacemaker implantation. Invasively, the optimal sensed AV delay was determined by LV dP/dt(max). The Doppler echocardiographic methods evaluated were the velocity-time integral (VTI) of the transmitral flow (EA VTI), diastolic filling time (EA duration), the VTI of the LV outflow tract or aorta (LV VTI), and Ritter's formula. Biventricular pacing with optimized interventricular and AV delay increased LV dP/dt(max) from 777 +/- 149 to 1,010 +/- 163 dynes/s (p<0.0001). The optimal AV delay with the EA VTI method was concordant with LV dP/dt(max) in 29 of 30 patients (r = 0.96), with EA duration in 20 of 30 patients (r= 0.83), with LV VTI in 13 patients (r = 0.54), and with Ritter's formula in none of the patients (r = 0.35). In conclusion, to obtain the optimal acute hemodynamic benefit of CRT, Doppler echocardiography is a reliable tool to optimize the AV delay compared with the invasive LV dP/dt(max). The measurement of the maximal VTI of mitral inflow is the most accurate method.

Aged↗
PubMed2006

Optimization of pulsed wave tissue Doppler to predict left ventricular reverse remodeling after cardiac resynchronization therapy.

OBJECTIVE: The optimal use of pulsed wave Doppler tissue imaging (DTI) in predicting left ventricular (LV) reverse remodeling after cardiac resynchronization therapy (CRT) was investigated. METHODS: DTI was performed in 69 patients before and 3 months after CRT. Echocardiographic reverse remodeling was observed in 38 patients. LV dyssynchrony was measured with the time to onset or peak systolic velocity in 2- and 6-basal segment models. RESULTS: The time to onset and either the standard deviation of 6 segments of > 20 ms or a delay of > or = 60 ms between any 2 of 6 segments had a similar predictive accuracy (sensitivity, 97% and 95%, respectively; specificity, 74% and 73%, respectively). The time to peak systolic velocity or evaluating 2 segments was less accurate. CONCLUSIONS: Evaluation of 6 segments is necessary to predict LV reverse remodeling after CRT. The time to onset of systolic velocity is superior to the time to peak velocity.

Aged↗
PubMed2006

Determination of the spatial orientation and shape of pulmonary vein ostia by contrast-enhanced magnetic resonance angiography.

AIMS: For catheter ablation of atrial fibrillation (AF), proper catheter positioning is crucial and depends on knowledge of pulmonary vein (PV) anatomy. The aim of this study was to assess PV spatial orientation and ostial shape by contrast-enhanced magnetic resonance angiography (CE-MRA). METHODS AND RESULTS: In 30 consecutive AF patients, CE-MRA was performed prior to ostial ablation. Using a centre-line technique, the PV ostium was defined perpendicular to this centre-line. Minimal and maximal ostial diameters, ostial perimeter, and angles in the anatomical frontal and transverse planes were measured. Twenty-one patients had four separate PVs. In four patients, there was a distinct right-middle PV and in five a common left common PV was found. Left-sided PV ostia were smaller and more elliptical than right-sided PVs. In the transverse plane, the ostia of both superior PVs were directed anteriorly (LS -15 +/- 13 degrees , RS -13 +/- 11 degrees ) and both inferior PV ostia were directed posteriorly (LI 23 +/- 15 degrees , RI 39 +/- 15 degrees ). In the frontal plane, both superior PV ostia pointed upwards (LS -27 +/- 14 degrees , RS -33 +/- 12 degrees ) while the inferior ostia were directed horizontally (LI 2 +/- 11 degrees , RI 3 +/- 13 degrees ). CONCLUSION: PV ostial shape and spatial orientation are variable and can be visualized adequately by CE-MRA.

Analysis of Variance↗
PubMed2006

Preservation of ventricular capture by anodal stimulation after dislodgment of an epicardial electrode.

A 58-year-old man had a bipolar epicardial left ventricular (LV) implanted for cardiac resynchronization therapy after a failed transvenous approach. The system was programmed in an LV tip-right ventricular coil configuration, but during follow-up loss of LV capture with recurrence of symptoms occurred. Changing to an LV tip-LV ring configuration restored LV pacing through anodal capture. Loss of cathodal capture was caused by dislodgment of the cathodal electrode due to a broken fixation suture. Anodal capture was used to reinstall resynchronization therapy, which resulted in clinical improvement. There were no adverse effects from anodal stimulation in a follow-up period of 6 months.

Bundle-Branch Block↗
PubMed2005

The hemodynamic effect of intrinsic conduction during left ventricular pacing as compared to biventricular pacing.

OBJECTIVES: We sought to investigate the effect of intrinsic conduction over the right bundle on the maximum rate of left ventricular pressure rise (LVdP/dt(max)) during left ventricular (LV) pacing compared to biventricular (BiV) pacing. BACKGROUND: Simultaneous BiV pacing and LV pacing both improve LV function in patients with heart failure and LV asynchrony. We studied the hemodynamic effect of intrinsic conduction leading to ventricular fusion during LV pacing. METHODS: In 34 patients with New York Heart Association functional class III or IV, sinus rhythm with normal atrioventricular (AV) conduction, left bundle branch block, QRS >130 ms, and optimal medical therapy, LVdP/dt(max) was measured invasively during LV and simultaneous BiV pacing. The AV interval was varied in four steps starting (AV1) with an AV interval 40 ms shorter than the intrinsic PQ time and decreased with 25% for each step. RESULTS: At AV1, LVdP/dt(max) was 996 +/- 194 mm Hg/s for LV pacing and 960 +/- 200 mm Hg/s for BiV pacing (p = 0.0009), with all patients showing ventricular fusion during LV pacing. At AV2, 21 patients had ventricular fusion with a LVdP/dt(max) of 983 +/- 213 mm Hg/s and 957 +/- 202 mm Hg/s for LV and BiV pacing, respectively. In the remaining 13 patients without fusion these values were 919 +/- 164 mm Hg/s and 957 +/- 174 mm Hg/s, respectively. The difference between LV and BiV at AV2 is significantly higher when fusion is present (p = 0.01). CONCLUSIONS: The LVdP/dt(max) is higher in LV than in BiV pacing provided that LV pacing is associated with ventricular fusion caused by intrinsic activation.

Aged↗
PubMed2005

The effect of anodal stimulation on V-V timing at varying V-V intervals.

We studied the effect of anodal capture at the ring electrode of the right ventricular (RV) lead on interventricular (V-V) timing during biventricular (BiV) pacing, in which left ventricular (LV) pacing was preceding RV pacing. The V-V interval was programmed from 80 to 4 ms (LV first) in the LV unipolar (LV tip--generator can) followed by the LV tip-RV ring pacing configuration. In the LV unipolar configuration, V-V programming leads to a continuous change in morphology of the QRS complex according to a change in collision of both activation fronts. When using the LV tip-RV ring configuration with anodal capture at the RV ring electrode no change in QRS morphology was recorded varying the V-V interval from 80 to 60 and 40 ms. However, at V-V intervals between 20 and 4 ms a change in morphology of the QRS complex was recorded, which was due to additional cathodal stimulation of the RV tip electrode during RV stimulation.

Aged↗
PubMed2004

Effect of optimizing the VV interval on left ventricular contractility in cardiac resynchronization therapy.

Simultaneous biventricular pacing improves left ventricular (LV) function in patients with heart failure and LV asynchrony. Proper timing of the interventricular pacing interval (VV interval) may further optimize LV function. We investigated the acute hemodynamic response of changing the VV interval using maximum LV dP/dt (LV dP/dt(max)) as a parameter for LV function. A biventricular pacemaker was implanted in 53 patients with severely impaired LV function, New York Heart Association class III and IV heart failure, left bundle branch block, LV asynchrony, and a QRS interval >150 ms. Optimization of the atrioventricular and VV intervals was based on measurement of LV dP/dt(max) by a 0.014-in sensor-tipped pressure guidewire. Measurement of LV dP/dt(max) was obtained without complications in all patients. In patients in sinus rhythm with ischemic cardiomyopathy or idiopathic dilated cardiomyopathy, mean improvements by simultaneous biventricular pacing were 17% and 18%, respectively. Patients in atrial fibrillation showed an improvement of 21%. Optimizing the VV interval resulted in further absolute increases of 8%, 7%, and 3%, respectively, in dP/dt(max) in the 3 groups. Maximum dP/dt was achieved with LV pacing first in 44 patients, simultaneous right and left ventricular pacing in 6 patients, and right ventricular pacing first in 3 patients. The mean optimal VV intervals were 37 +/- 32 ms in the atrial fibrillation group, 28 +/- 30 ms in the idiopathic dilated cardiomyopathy group, and 52 +/- 31 ms in the ischemic cardiomyopathy group. Optimization of the VV interval significantly increased LV dP/dt(max) compared with simultaneous biventricular pacing, and such optimization could be easily, accurately, and reliably evaluated by a 0.014-in sensor-tipped pressure guidewire.

Aged↗
PubMed2003

Successful implantation of a coronary sinus lead after stenting of a coronary vein stenosis.

Dislodgment of the coronary sinus lead was observed in a 79-year-old patient 8 months after implantation of a biventricular pacing system. A severe stenosis in the posterolateral branch, in which the lead was previously positioned, prohibited reinsertion of the lead. Because no other branches with adequate anatomy for lead insertion were available in the targeted area, the stenosis was dilated and stented. Subsequently, the left ventricular lead could be reimplanted in the same vessel.

Aged↗
PubMed2003

Implantation of a biventricular pacing system in a patient with a coronary sinus not communicating with the right atrium.

Intubation of the coronary sinus failed during implantation of a biventricular pacing system. An angiogram of the left coronary artery showed in the venous phase a coronary sinus not communicating with the right atrium. The coronary sinus was draining into a persistent left superior vena cava communicating with the left subclavian vein. The coronary sinus lead was successfully implanted through the persistent left superior vena cava, whereas the atrial and ventricular leads were implanted through the right superior vena cava in a conventional way.

Aged↗
PubMed2003

Lead extraction via the femoral artery of a left ventricular pacing lead inserted in the subclavian artery.

We describe the extraction of a pacing lead via the femoral artery 5 months after it was inadvertently introduced through the right subclavian artery and positioned in the left ventricle. The lead was dislocated from the myocardium by traction from the subpectoral area and subsequently removed with a retriever inserted through the femoral artery in order to minimize the risk of cerebral embolization and bleeding at the entry site. Bleeding was controlled at the subclavian artery entry site by temporary inflation of a balloon catheter inserted through the brachial artery, and at the insertion site of the retriever in the femoral artery with a closure device.

Catheterization, Peripheral↗
PubMed2003

Venous occlusion of the access vein in patients referred for lead extraction: influence of patient and lead characteristics.

The aim of this study was to determine the effect of patient and lead characteristics on occlusion of the access vein in pacemaker and ICD patients. Contrast venography of the access vein was obtained in 89 patients (17 patients with an ICD) scheduled for lead extraction. The indication for extraction was infection in 57 patients (systemic infection in 9) and lead malfunction in 32 patients. In 6 of the 89 patients, leads were introduced in both the right and left subpectoral area, resulting in a total of 95 venous entry sites. In 22 of these entry sites one lead was present, in 61 two leads, in 11 three, and in 1 four leads. The vessel patency was graded open or occluded. Occlusion of the subclavian vein occurred in four (13%) patients with lead malfunction versus 18 (32%) patients with infection (P = 0.07). In patients with systemic infection, 5 of 9 showed venous occlusion (P = 0.01 when compared to patients with malfunction, odds ratio 8.75, 95% confidence interval 1.21-64.11). Considered per entry site, the incidence of occlusion was 7 of 22 with one lead present, 17 of 61 with two leads, 0 of 11 with three leads, and 0 of 1 with four leads (P = 0.13). No patient had a superior vena caval occlusion. Patients with systemic infection have an increased risk of occlusion of the access vein. On the contrary, the study found no support for the concept that the risk of venous occlusion increases with a higher number of leads present.

Angiography, Digital Subtraction↗
PubMed2002

Cardiac stimulation caused by biogalvanic current during pacemaker implantation.

After lead positioning during implantation of a biventricular pacing system intermittent ventricular simulation was observed. There was no pacemaker connected to any of the leads, but ventricular capture could be provoked by an intermittent contact between the lead stylet, which was still partially inserted, and a self-retaining retractor. The same phenomenon was observed from the atrial lead.

Bundle-Branch Block↗
PubMed2002

Extraction of pacemaker and implantable cardioverter defibrillator leads: patient and lead characteristics in relation to the requirement of extraction tools.

Effective tools for extraction of pacemaker and ICD leads have been developed in the past decennium. This study investigated the necessity of using these tools in addition to direct traction in relation to patient and lead characteristics. The study encompasses first attempts at extraction of consecutive pacemaker and ICD leads from the subpectoral area. A stepwise extraction protocol was used with traction first (directly or with a locking stylet) followed by laser sheath extraction if not successful. The indication, patient age, time from implant, fixation mechanism, location, and insertion site of the leads were studied in relation to the outcome of traction. A total of 145 leads in 83 patients were extracted. Leads were implanted for 71 +/- 61 months. Indication for extraction was infection in 96 leads and malfunction in 49 leads. There were 90 ventricular leads including 16 ICD leads. Forty-nine (34%) leads were extracted with traction; in 96 (66%) leads a laser sheath was necessary. All leads implanted for < 6 months could be removed with traction alone. In a multivariate logistic regression model, time from implant was the main factor determining success of traction (P < 0.001), but in case of infection the success rate increased (P = 0.004). In conclusion, time from implant is the decisive factor to judge the potential efficacy of lead extraction with direct traction. If leads are implanted for 6 months, the availability of additional extraction tools is necessary when lead extraction is considered. In addition to time from implant, infected leads have a better chance to be removed with traction although it is a much weaker predictor.

Defibrillators, Implantable↗
PubMed2002

Transesophageal echocardiographic evaluation of tricuspid valve regurgitation during pacemaker and implantable cardioverter defibrillator lead extraction.

Chronically implanted ventricular pacing and defibrillator (ICD) leads can adhere to the tricuspid valve. This study examined the effect of lead extraction, and laser sheath extraction in particular, on tricuspid valve regurgitation. Lead extraction was first tried with traction using limited force followed by a laser sheath if not successful. Tricuspid valve regurgitation before and after extraction was evaluated with transesophageal echocardiography and graded from 0 (none) to 4 (severe). A change in regurgitation was considered clinically relevant if it increased with two grades or more and resulted in at least grade 3 regurgitation. Fifty ventricular leads were extracted in 43 consecutive patients, including 14 ICD leads. In 20 patients (group I) leads were removed without a (laser) sheath crossing the tricuspid valve, in 23 patients (group II) leads were extracted with lasing across the valve. The mean time from implant was 43 +/- 43 months and 99 +/- 78 months, respectively, (P = 0.007). Tricuspid regurgitation increased in five (12%) patients. In group I only in one patient the laser failed proximal of the valve and forceful traction was subsequently used, and in group II this occurred in four (17%) patients. This difference did not reach statistical significance even excluding the patient from group I (P = 0.111). The increase of tricuspid regurgitation cautions against indiscriminate extraction of superfluous leads. There is a trend that when tools like a laser sheath are necessary the chance of tricuspid valve damage increases.

Defibrillators, Implantable↗