Septal versus apical pacing sites in permanent right ventricular pacing: The multicentre prospective SEPTAL-PM study.

BACKGROUND: The optimal right ventricular pacing site for patients requiring pacemaker implantation for permanent atrioventricular block is a matter of debate. Long-term right ventricular apical pacing has been associated with left ventricular ejection fraction impairment and heart failure. Right ventricular septal pacing has been proposed as an alternative. AIM: The aim of this randomized prospective multicentre trial was to compare left ventricular remodelling and outcomes between right ventricular apical and septal pacing after mid-term follow-up. METHODS: Patients requiring pacemaker implantation for high-degree atrioventricular block were enrolled and randomized in a 1:1 fashion to receive a right ventricular apical or septal lead. RESULTS: A total of 141 patients were included, 69 in the septal group and 72 in the apical group. Both groups exhibited similar left ventricular ejection fractions after 18 months of follow-up (septal 57.1±11.9% vs. apical 57.4±13.4%), and left ventricular ejection fraction variation was similar in the two groups at the end of follow-up (septal -1.5±13.2% vs. apical 0.3±13.3%). Additionally, left ventricular volume, quality of life and 6-minute walk distance were similar in the two groups. However, patients in the septal group were more likely to be asymptomatic, with a significantly lower concentration of N-terminal prohormone of brain natriuretic peptide. Lastly, lead position did not impact 18-month survival. CONCLUSION: Pacing from the right ventricular apex does not have any detrimental effect on left ventricular systolic function compared with septal pacing over an 18-month period.

Concordance between mechanical and electrical dyssynchrony in heart failure patients: a function of the underlying cardiomyopathy?

BACKGROUND: Cardiac resynchronization therapy (CRT) improves heart failure (HF) symptoms through a reduction of cardiac mechanical dyssynchrony. Mechanical dyssynchrony is currently estimated by electrical dyssynchrony (QRS duration). It is known that electrical and mechanical dyssynchrony are not well correlated in HF patients. However, there is limited information about whether this relationship might be influenced by the underlying cardiomyopathy. METHODS: Doppler echocardiography was performed in 88 patients presenting with heart failure due to ischemic (n = 42) or nonischemic (n = 46) heart disease, left ventricular ejection fraction <40%, New York Heart Association class II-IV, regardless of their QRS duration. Interventricular dyssynchrony was assessed by the time interval between preaortic and prepulmonary ejection times. Intraventricular dyssynchrony was ascertained by (1) the delay between the earliest and the latest peak negative longitudinal strain recorded in the basal and mid-segments of the lateral and septal walls (TMinMax) and (2) the standard deviation of time-to-peak in the same segments (SDdys). RESULTS: The correlation coefficient between QRS duration and mechanical interventricular dyssynchrony was r = 0.47 (P < 0.001) in patients with nonischemic disease and nonsignificant in patients with ischemic disease. Similarly, the correlation coefficient between QRS duration and mechanical intraventricular dyssynchrony was significant in patients with nonischemic disease (r = 0.37, P = 0.01 for TMinMax; r = 0.42, P = 0.003 for SDdys) and nonsignificant in patients with ischemic disease. CONCLUSION: The concordance between electrical dyssynchrony assessed by QRS duration and mechanical dyssynchrony assessed by myocardial strain is dependent upon the underlying cardiomyopathy. This observation may improve our understanding of the various responses observed in CRT patients.

[Managing bradycardia in adults]. / Conduite a tenir devant une bradycardie de l'adulte.

Bradycardia represents a common cause of requirement for specialist advice and it looks sometimes difficult to evaluate its pathological criteria and its medical management. The authors remind the physiological mechanisms and their aetiologies, cardiac or not. Many complementary exams can be employed but a rigorous strategy is necessary, based on the use of electrocardiogram, Holter ECG, implantable loop recorder, stress test, cardiac echography, tilt testing, electrophysiological study. Once the diagnostic established, the next fundamental step consists on a rigorous evaluation of severity in order to recognize the real urgency which require an hospitalization and to initiate rapidly the most appropriate treatment, sometimes before having the complete diagnosis, or to take in charge ambulatory the less severe cases all the more a reversible causes is identified. The situation often needs to take our time to avoid conceding too easily the definitive cardiac pacing. North American guidelines concerning cardiac pacing represent at least the references which we have to follow as often as possible particularly concerning atypical cases.

Acute effects of biventricular pacing on right ventricular function assessed by tissue Doppler imaging.

AIMS: The benefits of cardiac resynchronization therapy (CRT) on functional status, left ventricular (LV) remodelling and survival in patients with drug-refractory congestive heart failure (CHF), LV systolic dysfunction, and wide QRS have been demonstrated in randomized trials. However, the impact of CRT on right ventricular (RV) function, an independent prognostic factor in CHF remains questionable. This study examined the acute effects of various pacing modes on RV function in recipients of CRT systems. METHODS AND RESULTS: Echocardiographic examinations were performed in 15 patients (median age: 67 years, range 49-78), to compare RV function during atrial (AAI), RV and LV pacing, and biventricular (BiV) pacing, in random order. At baseline, the median LV ejection fraction was 20% (range 10-35) and the median LV end-diastolic diameter was 78 mm (range 62-85). Right ventricular function was impaired, with a median 36% fractional shortening of RV surfaces (7-59). Tissue Doppler systolic peak of velocity (Sa) recorded at the tricuspid annulus increased significantly from 9.9 cm/s (range 4.7-16.5) during AAI pacing, 10 cm/s (range 5.4-20.3) during RV pacing, and 11.7 cm/s (range 4.6-16.7) during LV pacing to 12.6 cm/s (range 6.6-19.1) during BiV pacing (P < 0.01). Trends toward improvements in other indices of RV function, particularly myocardial performance index and systolic excursion of the tricuspid annulus, were also observed. CONCLUSIONS: This short-term study showed a significant improvement in RV systolic function during BiV pacing compared with AAI, RV, or LV pacing in CRT recipients.

Clinical and electrocardiographic predictors of a positive response to cardiac resynchronization therapy in advanced heart failure.

AIMS: Cardiac resynchronization therapy (CRT) is an effective treatment for refractory congestive heart failure (CHF). However, up to 30% of patients do not respond to CRT. The aim of this study was to identify clinical and electrocardiographic (ECG) predictors of a positive response to CRT. METHODS AND RESULTS: This retrospective study included 139 consecutive patients successfully implanted with a CRT device (mean age, 68+/-9 years, 113 men). At baseline, 69% of patients were in New York Heart Association (NYHA) functional class III, and 31% in class IV, mean left ventricular ejection fraction was 21+/-6%, and mean QRS duration was 188+/-28 ms. In each patient, left and right ventricular leads were placed to attain the shortest QRS duration during biventricular stimulation. Patients were classified at 6 months as responders to CRT (n=100) if they were alive, they had not been re-hospitalized for management of CHF, and the NYHA class had decreased by 1 point, and/or peak VO(2) or 6 min hall-walk increased by >10%. All others were classified as non-responders (n=38; one patient was lost to follow-up). Uni- and multivariate logistic regression analyses were performed to detect a pre- or intra-operative predictor of a positive response to CRT. Among multiple demographic, clinical, and ECG variables, the amount of QRS shortening (DeltaQRS) associated with biventricular stimulation was the only independent predictor of a positive (37+/-23 ms) vs. negative (11+/-23 ms) response to CRT (P<0.001). CONCLUSION: A positive response to CRT was observed in 73% of patients at 6 months and predicted only by DeltaQRS.