The main objective of this study was to assess if the benefits of biventricular (BiV) pacing observed during the crossover phase were sustained over 12 months.
MUltisite STimulation In ...Cardiomyopathies (MUSTIC) is a randomized controlled study intended to evaluate the effects of BiV pacing in patients with New York Heart Association (NYHA) class III heart failure and intraventricular conduction delay.
Of 131 patients included, 42/67 in sinus rhythm (SR) and 33/64 in atrial fibrillation (AF) were followed up longitudinally at 9 and 12 months by 6-min walked distance, peak oxygen uptake (peak VO2), quality of life by the Minnesota score, NYHA class, echocardiography, and left ventricular ejection fraction by radionuclide technique.
At 12 months, all SR and 88% of AF patients were programmed to BiV pacing. Compared with baseline, the 6-min walked distance increased by 20% (SR) (p = 0.0001) and 17% (AF) (p = 0.004); the peak VO2by 11% (SR) and 9% (AF); quality of life improved by 36% (SR) (p = 0.0001) and 32% (AF) (p = 0.002); NYHA class improved by 25% (SR) (p = 0.0001) and 27% (AF) (p = 0.0001). The ejection fraction improved by 5% (SR) and 4% (AF). Mitral regurgitation decreased by 45% (SR) and 50% (AF).
The clinical benefits of BiV pacing appeared to be significantly maintained over a 12-month follow-up period.
Obstructive sleep apnea (OSA) is associated with several cardiovascular conditions. Some pacemakers feature specific algorithms detecting respiratory cycles and deriving indices well correlated with ...the identification of polysomnography-confirmed severe OSA.
The purposes of this study were to analyze respiratory disturbances measured by a validated algorithm in clinical practice and to describe their variability over time and their association with atrial fibrillation.
Fifty-eight patients implanted with dual-chamber LivaNova REPLY 200 DR or KORA 100 DR pacemakers measuring a respiratory disturbance index (RDI) were included. An RDI >20 events per hour of sleep is well correlated with severe OSA as determined by polysomnography. Patients with >10% nights with invalid RDI measurements were excluded.
The RDI could be measured during 98% of nights. During a mean follow-up of 187 ± 123 days, the individual mean RDI was 19.9 ± 12.7 and was superior to 20 in 24 patients (41%). An RDI >20 events/h in at least 1 night was observed in 52 patients (90%). The mean day-to-day RDI variability in individual patients was 19% ± 21%. Patients with the highest burden of severe OSA (as defined by ≥75% of nights with RDI >20 events/h) were older, had a higher prevalence of hypertension, and were more often implanted for atrioventricular block than patients with lower burden of severe OSA. No RDI burden or cutoff was a predictor of atrial fibrillation occurrence.
OSA is frequent in patients with a pacemaker and is reliably detected by pacemakers. OSA is highly variable and could probably be best analyzed in terms of burden.
The prevalence of conduction disturbances, particularly left bundle branch block (LBBB), is strongly correlated with age and with the presence of cardiovascular disease. LBBB has been reported to ...affect approximately 25% of the heart failure (HF) population and it is likely that the deleterious role of such conduction disorders in the progression to HF has been underestimated.
The purpose of this article is to review the data from the literature indicating that LBBB may have a causative role, mediated through the resulting intra-ventricular asynchrony, in the deterioration of cardiac function and the development of cardiac remodelling and HF. It also aims to address the potential for future clinical therapies for this conduction disorder.
Background:
Cardiac resynchronization therapy (CRT) is recommended for patients with NYHA class III-IV refractory heart failure (HF), ejection fraction <35% and a QRS >120ms. We attempted to identify ...responders to CRT from echocardiographic (echo) indices of mechanical dyssynchrony in patients with QRS < 150 ms.
Methods and results:
The study enrolled 51 men and 9 women (mean age: 64.5years) in NYHA class III (n=54) or IV (n=6) presenting with a mean ejection fraction: 25.7%, LV end-diastolic diameter: 69.1mm, and QRS = 121 ± 19 ms. All patients were implanted with a CRT system and followed for 1year. Implantation was preceded and followed by clinical, functional and Doppler (D)-echo evaluation. The primary combined endpoint included 1) death from any cause, 2) HF-related hospitalisations, and 3) NYHA class at 6 months. Before implant, 27 patients had ≥ 1 echo criterion of mechanical dyssynchrony (DES+ group) and 33 had no evidence of dyssynchrony (DES− group). At 12months, 8 patients (4 per group) had died, 7 from HF. As regards the primary endpoint at 6 months, 33 patients (55%) had improved, 10 (16%) were unchanged, and 17 (29%) had deteriorated. Clinical improvement was observed in 19 of 27 DES+ (70%), versus 14 of 33 DES− (42%) patients (P<0.04). Baseline QRS duration did not predict response to CRT.
Conclusions:
In this population of HF patients with QRS < 150 ms, the presence of mechanical dyssynchrony at baseline D-echo examination, but not the QRS width, predicted 6-month clinical response to CRT.
Purpose
Electrophysiological studies and radiofrequency catheter ablations require single or multiple sheath placements through femoral vein cannulation. The objective of this study was to determine ...the incidence, predictors, and outcomes of deep vein thrombosis (DVT) following such procedures.
Methods and results
We prospectively enrolled 220 consecutive patients with a median age of 70 60–79 years. The median duration of the procedures from insertion to removal of sheaths was 45 30–75 min. At least two sheaths were inserted in 158 (72 %) of the cases. Duplex ultrasonography evaluation of the lower leg veins was performed 6 h after the procedure and revealed common femoral vein thrombosis in 11 (5 %) patients. All thrombi were partial and none was complete. Thrombi were mobile in four patients and extended to the external iliac vein in three patients. None of the patients presented with clinical signs of DVT or pulmonary embolism. Anticoagulation was prescribed for 2–4 weeks and a follow-up duplex ultrasonography obtained in the first seven patients revealed complete resolution of thrombi in all cases. On multivariate analysis, two predictors of thrombosis occurrence were identified: a greater sum of sheath diameters (odds ratio, 1.41 95 % confidence interval, 1.25–1.60 per 1-French increase;
p
< 0.001) and a longer procedural duration (odds ratio, 1.02 95 % confidence interval, 1.00–1.04 per 1-min increase;
p
= 0.04).
Conclusions
Asymptomatic femoral DVT occur in 5 % of electrophysiological studies and right-heart radiofrequency catheter ablations, particularly when large sheaths are inserted for a longer period. The role of anticoagulation in this clinical setting warrants further evaluation.
Purpose
Atrial fibrillation (AF) is a major cause of ischemic strokes, and it is assumed that occult intermittent episodes of AF are responsible for some of the seemingly cryptogenic strokes. Cardiac ...pacemakers feature rhythm diagnostic capabilities and data storage. We investigated whether pacemaker memory interrogation led to identification of undetected AF episodes prior to cryptogenic strokes.
Methods
The study enrolled all patients admitted between June 2010 and July 2013 for an acute cryptogenic stroke and who were implanted with a permanent pacemaker. Patients with a history of AF and a history of stroke with an identifiable origin were excluded. Pacemaker memories were interrogated to determine the presence of AF prior to the stroke and its temporal relationship with the stroke.
Results
Fourteen patients (nine men and five women) with a median (interquartile range) age of 84.5 (82.25–87.5) years were included. Median CHADS
2
and CHA
2
DS
2
-VASc scores were 2 (1–2.75) and 3.5 (3–4), respectively. Pacemaker memories were activated in 13 patients with atrial arrhythmia detection based on an atrial cutoff rate in 8 patients and on the detection of atrial rate acceleration in 5 patients. Electrograms were available for review in 10 patients. Unknown AF or atrial flutter was diagnosed previous to the stroke in six (43 %) patients. Four patients experienced more than one arrhythmia episode. The last episode occurred in the 48 h prior to stroke in three patients and in the previous 4 weeks in five patients. Anticoagulation was started after the stroke in all of these six patients.
Conclusions
Pacemaker interrogation has a high diagnostic yield in seemingly cryptogenic stroke, with frequent detection of occult AF. The causal link between AF and stroke is convincingly reinforced by their close temporal proximity, and anticoagulation is warranted in this clinical situation.
Our objective was to improve hemodynamics by synchronous right and left site ventricular pacing in patients with severe congestive heart failure (CHF). Previous studies reported a benefit of dual ...chamber pacing with a short AV delay in patients with severe CHF. Other works, however, show contradictory results. Deleterious effects due to a desynchronization of right (RV) and left ventricular (LV) contractions have been suggested. This study included eight subjects with widened QRS and end‐stage heart failure despite maximal medical therapy, who refused, or were not eligible to undergo heart transplantation. Each patient underwent a baseline, invasive hemodynamic evaluation with insertion of three temporary leads to allow different pacing configurations, including RV apex and outflow tract pacing, and biventricular pacing between the RV outflow tract and LV and RV apex and LV. According to the results of this baseline study, the configuration of preexistent pacemakers was modified or new systems were implanted to allow biventricular pacing, which, in patients with sinus rhythm, was atrial triggered. Biventricular pacing increased the mean cardiac index (CI) by 25% (from a baseline of 1.83 ± 0.30 L/min per m2, P < 0.006), decreased the mean V wave by 26% (from a baseline of 36 ± 12 mmHg, P < 0.004), and decreased pulmonary capillary wedge pressure by 17% (from a baseline of 31 ± 10 mmHg, P < 0.01). Four patients died (1 preoperatively, 1 intraoperatively, 2 within 3 months, and 1 of a noncardiac cause). The four surviving patients have clinically improved from New York Heart Association Functional Class IV to Class II. In these survivors, CI decreased by 15% (P < 0.007) when multisite pacing was turned off during follow‐up. In patients with end‐stage heart failure, multisite pacing may be associated with a rapid and sustained hemodynamic improvement.
The choice of resynchronization therapy between with (CRT-D) and without (CRT-P) a defibrillator remains a contentious issue. Cause-of-death analysis among CRT-P, compared with CRT-D, patients could ...help evaluate the extent to which CRT-P patients would have additionally benefited from a defibrillator in a daily clinical practice.
A total of 1705 consecutive patients implanted with a CRT (CRT-P: 535 and CRT-D: 1170) between 2008 and 2010 were enrolled in CeRtiTuDe, a multicentric prospective follow-up cohort study, with specific adjudication for causes of death at 2 years. Patients with CRT-P compared with CRT-D were older (P < 0.0001), less often male (P < 0.0001), more symptomatic (P = 0.0005), with less coronary artery disease (P = 0.003), wider QRS (P = 0.002), more atrial fibrillation (P < 0.0001), and more co-morbidities (P = 0.04). At 2-year follow-up, the annual overall mortality rate was 83.80 95% confidence interval (CI) 73.41-94.19 per 1000 person-years. The crude mortality rate among CRT-P patients was double compared with CRT-D (relative risk 2.01, 95% CI 1.56-2.58). In a Cox proportional hazards regression analysis, CRT-P remained associated with increased mortality (hazard ratio 1.54, 95% CI 1.07-2.21, P = 0.0209), although other potential confounders may persist. By cause-of-death analysis, 95% of the excess mortality among CRT-P subjects was related to an increase in non-sudden death.
When compared with CRT-D patients, excess mortality in CRT-P recipients was mainly due to non-sudden death. Our findings suggest that CRT-P patients, as currently selected in routine clinical practice, would not potentially benefit with the addition of a defibrillator.
This paper deals with the numerical simulation of electrocardiograms (ECG). Our aim is to devise a mathematical model, based on partial differential equations, which is able to provide realistic ...12-lead ECGs. The main ingredients of this model are classical: the bidomain equations coupled to a phenomenological ionic model in the heart, and a generalized Laplace equation in the torso. The obtention of realistic ECGs relies on other important features—including heart-torso transmission conditions, anisotropy, cell heterogeneity and His bundle modeling—that are discussed in detail. The numerical implementation is based on state-of-the-art numerical methods: domain decomposition techniques and second order semi-implicit time marching schemes, offering a good compromise between accuracy, stability and efficiency. The numerical ECGs obtained with this approach show correct amplitudes, shapes and polarities, in all the 12 standard leads. The relevance of every modeling choice is carefully discussed and the numerical ECG sensitivity to the model parameters investigated.
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