Sander G. Molhoek

Usefulness of myocardial tissue Doppler echocardiography to evaluate left ventricular dyssynchrony before and after biventricular pacing in patients with idiopathic dilated cardiomyopathy

Tissue Doppler imaging allows assessment of left ventricular dyssynchrony and resynchronization after biventricular pacing.

QRS duration and shortening to predict clinical response to cardiac resynchronization therapy in patients with end-stage heart failure

Despite current selection criteria (NYHA Class III–IV, LVEF < 35%, QRS > 120 ms with LBBB), 30% of patients do not benefit from cardiac resynchronization therapy (CRT). The use of QRS duration as selection criteria for CRT has not been evaluated systematically yet. Accordingly, the value of QRS duration at baseline (and reduction in QRS duration after CRT) to predict responders was studied. Patients were evaluated at baseline and after 6 months of CRT for NYHA Class, quality of life score, and 6‐minute walk test. QRS duration was evaluated before, directly after implantation, and after 6 months of CRT. Sixty‐one patients were included; 45 (74%) patients were classified as responders (improvement of NYHA Class, 6‐minute walking distance and quality of life score) and 16 (26%) as nonresponders. QRS duration at baseline was similar between the two groups: 179 ± 30 ms versus 171 ± 32 ms, NS. Directly after implantation, QRS duration was reduced from 179 ± 30 ms to 150 ± 26 ms (P < 0.01) in responders; nonresponders did not exhibit this reduction (171 ± 32 ms vs 160 ± 26 ms, NS). After 6 months of CRT, QRS shortening was only observed in responders (from 179 ± 30 ms to 159 ± 25 ms, P < 0.01). ROC curve analysis showed that a reduction in QRS duration > 10 ms had a high sensitivity (73%) with low specificity (44%); conversely, a > 50 ms reduction in QRS duration was highly specific (88%) but not sensitive (18%) to predict response to CRT. No optimal cutoff value could be defined. QRS duration at baseline is not predictive for response to CRT; responders exhibit a significant reduction in QRS duration after CRT, but individual response varies highly, not allowing adequate selection of responders. (PACE 2004; 27:308–313)

Effectiveness of resynchronization therapy in patients with end-stage heart failure

Biventricular pacing has been introduced to treat patients with end-stage heart failure, and short-term results of this technique are promising. Because data on longer follow-up are limited to 3-month follow-up, the sustained effect of biventricular pacing is unclear and long-term survival is unknown. Forty patients with end-stage heart failure in New York Heart Association (NYHA) functional class III or IV with left ventricular (LV) ejection fraction (EF) <35%, QRS duration >120 ms, and left bundle branch block morphology received a biventricular pacemaker. At baseline, and at 3 and 6 months after implantation, the following parameters were evaluated: NYHA class, Minnesota quality-of-life score, QRS duration on surface electrocardiogram, 6-minute walking distance, and LVEF. Long-term follow-up was obtained for up to 2 years. All clinical parameters improved significantly at 3 months and remained unchanged at 6-month follow-up. LVEF increased from 24 +/- 9% to 34 +/- 11%. Before implantation, patients were hospitalized (for congestive heart failure) an average of 3.9 +/- 5.3 days/year compared with 0.5 +/- 1.5 days/year after implantation. Long-term follow-up showed a survival of 87.5% at 2 years. Thus, biventricular pacing resulted in improvement of symptoms and quality of life, accompanied by improvement in 6-minute walking distance and LVEF. These effects were observed at 3 months after implantation and were maintained at 6-month follow-up. Moreover, 2-year survival was excellent.

Cardiac resynchronisation therapy in chronic atrial fibrillation: impact on left atrial size and reversal to sinus rhythm

Objective: To evaluate the impact of long term cardiac resynchronisation therapy (CRT) on left atrial and left ventricular (LV) reverse remodelling and reversal to sinus rhythm (SR) in patients with heart failure with atrial fibrillation (AF). Patients: 74 consecutive patients (age 68 (8) years; 67 men) with advanced heart failure and AF (20 persistent and 54 permanent) were implanted with a CRT device. Main outcome measures: Patients were evaluated clinically (New York Heart Association (NYHA) class, quality of life, six minute walk test) and echocardiographically (LV ejection fraction, LV diameters, and left atrial diameters) before and after six months of CRT. Additionally, restoration of SR was evaluated after six months of CRT. Results: NYHA class, quality of life score, six minute walk test, and LV ejection fraction had improved significantly after six months of CRT. In addition, left atrial and LV end diastolic and end systolic diameters had decreased from 59 (9) to 55 (9) mm, from 72 (10) to 67 (10) mm, and from 61 (11) to 56 (11) mm, respectively (all p < 0.01). During implantation 18 of 20 (90%) patients with persistent AF were cardioverted to SR. At follow up 13 of 18 (72%) patients had returned to AF and none had spontaneously reverted to SR; thus, only 5 of 74 (7%) were in SR. Conclusion: Six months of CRT resulted in significant clinical benefit with significant left atrial and LV reverse remodelling. Despite these beneficial effects, 93% of patients had not reverted to SR.

Atrial and brain natriuretic peptides as markers of response to resynchronisation therapy

Cardiac resynchronisation therapy (CRT) has recently been introduced to treat patients with drug refractory heart failure.1,2 Studies have demonstrated immediate haemodynamic improvement after CRT, followed by improvement in symptoms, quality of life, and exercise capacity.1,2 Although the majority of patients respond well to CRT, in 20% of patients symptoms do not improve. The main problem is the lack of objective parameters to measure the effect of CRT. Natriuretic peptides are now used in studies involving patients with heart failure.3 The value of these markers to objectively assess response to CRT was evaluated in this study. Based on traditional selection criteria (New York Heart Association (NYHA) functional class III–IV, left ventricular ejection fraction (LVEF) 120 ms, and left bundle branch block configuration), 30 consecutive patients, of whom 23 were men (mean (SD) age 65 (12) years), underwent biventricular pacemaker implantation; 13 had ischaemic and 17 had idiopathic dilated cardiomyopathy. Medication consisted of diuretics, angiotensin converting enzyme inhibitors, spironolactone, β blockers, and/or amiodarone, and remained unchanged during the entire study. The day before implantation, echocardiography was performed in combination with tissue Doppler imaging (TDI) (to assess left ventricular dyssynchrony). Clinical evaluation included assessment of NYHA class, ECG (QRS duration, morphology), quality of life, and six minute walking distance. Blood samples were obtained for the analysis of atrial natriuretic peptide (ANP) …

Requirement for coronary sinus lead interventions and effectiveness of endovascular replacement during long-term follow-up after implantation of a resynchronization device

AIMS The aim of this study was to assess the requirement for coronary sinus (CS) lead intervention after cardiac resynchronization therapy (CRT) and to evaluate the effectiveness of endovascular replacement. METHODS AND RESULTS All patients receiving a CRT device with CS lead in the Leiden University Medical Center in the period from 1999 to 2007 were prospectively evaluated and followed. Five hundred and seventy-seven patients were successfully implanted with a CRT device. Nine (1.6%) patients were lost to follow-up. The remaining 568 patients were included in the analysis. During a median follow-up time of 645 days (inter-quartile range, 260-1148), 7% of the patients required a CS lead intervention. Cause of the intervention was an elevated threshold (n = 13), loss of capture (n = 20), or intractable phrenic nerve stimulation (n = 6). Fifteen patients (38%) required a CS lead intervention before first scheduled follow-up (2 months after implantation). Thirteen patients (33%) warranted a CS lead intervention more than 6 months after implantation. The first endovascular replacement was successful in 86% (32 of 37), whereas a second endovascular approach failed in 66% (2 of 3). CONCLUSION The long-term requirement for CS lead interventions is 7%. Endovascular repositioning or replacement is successful in the majority of cases.

Evaluation of resynchronization of contractile function following biventricular pacing using colour tissue Doppler imaging

Biventdcular (BV) pacing is evaluated as an alternative treatment for patients with dilated cardiomyppathy (both ischemic and non-ischemic) and end-stage heart failure. Colour tissue Doppler imaging using echocardiography allows noninvasive, quantitative assessment of radial motion in the long-axis with measurement of peak systolic velocity timing. The aim of the present study was to evaluate quantitatively, the systolic performance of the left ventricle and the resynchrenization of contraction (before vs after implantation). Patients and methods: 25 patients with dilated cardiomyopathy (11 ischemic), NYHA class III or IV, QRS duration >120 ms received a biventricular pacemaker. Routine 2D echo and colour tissue Doppler imaging were performed before and within 1 week following implantation. LVEF was assessed using the biplane Sampsons method.Peak systolic velocity (PSV) and time to PSV (TPV) were assessed in 4 regions (basal anterior, inferior, lateral and septal). By averaging the TPV from all 4 regions, a synchronization index was dedved from these measurements. Reaults: LVEF improved by 9±9% following pacing; 17 patients improved LVEF 5% or more. The change in PSV in the septal and lateral regions related significantly to the change in LVEF (r=0.74, r=0.62).The change in synchronization index before vs after pacing (as a measurement of REsynchronization) was related to the change in LVEF (y=120x+5.6, r=0.79, P<0,01). Using a change in synchronization of 40, a sensitivity of 76% and a specificity of 100% were obtained to predict improvement of LVEE Conclusion: Colour tissue Doppler imaging allows assessment of resynchronization of contraction following BV pacing and may be used to predict change in LVEE

Anatomical perspective on radiofrequency ablation of AV nodal reentry tachycardia after Mustard correction for transposition of the great arteries.

A case of radiofrequency catheter ablation of atrioventricular (AV) nodal reentry tachycardia, in a patient with transposition of the great arteries after venous rerouting according to Mustard, is described. An electroanatomical map of the His and AV nodal region was created from inside the systemic venous atrium. Retrograde mapping of the pulmonary venous atrium was performed and the arterial catheter retracted to a position in close proximity to the venous catheter inside the intraatrial baffle. This position was chosen to deliver radiofrequency current. (PACE 2012; 35:e287–e290)

Cyclic Appropriate Mode Switching and Inappropriate Back Switching of a Biventricular Pacemaker During Atrial Tachyarrhythmia

In patients with resynchronization devices and intact intrinsic AV conduction, atrial tachyarrhythmias may give rise to high ventricular rates, resulting in inhibition of (bi)ventricular pacing and concomitant lack of therapeutic effects of the device. This report presents a patient with atrial arrhythmias in whom mode switching and back switching of the biventricular pacemaker occurred, due to special timing of the atrial and ventricular deflections. This case report stresses the importance of strenuous treatment of atrial arrhythmias in patients with resynchronization devices. (PACE 2004; 27:249–251)

Eligibility for biventricular pacing in patients with an implantable cardioverter defibrillator

Implantable cardioverter defibrillator (ICD)-therapy prevents sudden death in patients at high risk, but incidence of death due to heart failure remains unaltered. Recent data suggest that biventricular (BV) pacing is useful in patients with heart failure. It is unclear, how many patients with an ICD indication may have an indication for BV pacing. Therefore all patients who received an ICD were analyzed for eligibility of BV pacing using the following criteria: NYHA class III or IV, QRS duration >120 ms, depressed LVEF. Three hundred and ninety consecutive patients received an ICD from June 1996 to March 2001. Underlying disease was ischemic heart disease in 66%. In the 390 patients the mean LVEF was 36+/-17%, 20% were in NYHA class III-IV and 16% were in NYHA class II with an LVEF <30%. Of these 140 patients, 79 had a QRS duration >120 ms. Thus, 79 (20%) patients were eligible for BV pacing in addition to ICD-therapy. Patients who received a BV pacemaker in addition to ICD-therapy had a superior survival, improved in NYHA class and showed a significantly lower hospitalization rate as compared to patients who received an ICD only. Screening for eligibility of BV pacing may be considered in patients with CHF scheduled for ICD implantation.