Author + information
- Jack Rickard,
- Edmond Cronin,
- David Spragg,
- Alan Cheng,
- Wai Hong Tang,
- Richard Grimm,
- Bruce Wilkoff and
- Niraj Varma
Based on the results of one randomized controlled trial, cardiac resynchronization therapy (CRT) is not thought to be of benefit to patients with a narrow QRS complex. Whether a subset of patients with a narrow QRS complex respond to CRT has not been examined.
We extracted clinical, echocardiographic, and electrocardiographic data on 945 consecutive patients presenting for CRT. For inclusion in the final cohort patients met the following criteria: QRS complex ≤ 130 ms, pre and appropriately timed follow up echocardiograms, and a baseline LVEF ≤ 35%. Patients who participated in the RETHINQ study were excluded. Response was defined as an absolute reduction in LVESV of ≥15% from baseline. A multivariate model was created to determine factors associated with response.
72 patients met inclusion criteria of whom 26 (31.1%) met criteria for response. The large majority of the patients included had CRT for heart failure with a borderline prolonged QRS complex (77.8%). 9.7% had echocardiographic evidence of dyssynchrony, 8.3% were deemed to have a new requirement for frequent ventricular pacing, and 4.2% underwent a concomitant AV node ablation. There was no difference in the baseline QRS complex duration (ms)(115.2±14.7 vs. 119.7±12.4, p=0.26), incidence of ischemic cardiomyopathy (61.5% vs. 58.7%, p=1.0), male gender (80.8% vs. 90.5%, p=1.0), baseline ejection fraction (%)(20.8±7.2 vs. 22.2±6.8, p=0.42), or history of atrial fibrillation (53.8% vs. 41.3%, p=0.81) between responders and non-responders, respectively. Other common co-morbidities such as chronic kidney disease and cardiac medication usage were similar between the two groups. In multivariate analysis, no baseline factors were predictive of response.
Patients with heart failure and a narrow complex undergoing CRT have a low response rate (31.1%). No clinical characteristics including those traditionally associated with response among patients with a wider QRS duration were predictive of response in this population. There does not appear to be a subset of patients with a narrow QRS duration likely to respond to CRT.
Moderated Poster Contributions
Poster Sessions, Expo North
Sunday, March 10, 2013, 3:45 p.m.-4:30 p.m.
Session Title: Arrhythmias: Devices Ill – Use of Arrhythmia Devices in Novel Patient Populations
Abstract Category: 8. Arrhythmias: Devices
Presentation Number: 1235M-27
- 2013 American College of Cardiology Foundation