What is the clinical evidence from this study?

Study design: Observational. Population: Atrioventricular block (AVB) (n=114). Intervention: Paced QRS duration ≥ 180 msec vs. Paced QRS duration < 180 msec. Primary outcome: Incidence of underlying heart disease (p=<0.01).

July 1, 1992

Clinical Significance of QRS Duration During Ventricular Pacing

Q: What are the key findings of this study?

A paced QRS duration ≥180 msec in patients with atrioventricular block was associated with a higher incidence of underlying heart disease (83% vs 32%, P<0.01) and impaired left ventricular function.

Key Result

A paced QRS duration ≥180 msec in patients with atrioventricular block was associated with a higher incidence of underlying heart disease (83% vs 32%, P<0.01) and impaired left ventricular function.

Study Design

Type

Observational (n=114)

PICO

Population

114 patients who had undergone pacing for atrioventricular block, evaluated during a follow-up period.

Exposure / Comparator

Paced QRS duration ≥ 180 msec vs Paced QRS duration < 180 msec

Primary Outcome

Incidence of underlying heart disease, p=<0.01

Main Result

Absolute Event Rate: 83% vs 32%

p-value: p=<0.01

Abstract

To clarify the clinical significance of an abnormally prolonged paced QRS duration, we studied 114 patients who had undergone pacing for atrioventricular block (AVB). Patients were divided into two groups: group I consisted of 29 patients with at least one paced QRS duration greater than or equal to 180 msec during the follow-up period; group II consisted of 85 patients with paced QRS durations less than 180 msec. The clinical background, QRS complexes before pacing, and the echocardiographic findings were assessed. Males (P less than 0.05), those with H-V block (P less than 0.05) and a wider QRS complex of conducted and escape beats (both P less than 0.01) were dominant in group I. The incidence of underlying heart disease was greater in group I than in group II (83% vs 32%, P less than 0.01). Reduced left ventricular ejection fraction (LVEF) and increased left ventricular end-diastolic dimension (LVDd) were more prominent in group I than in group II (LVEF 0.49 +/- 0.17 vs 0.68 +/- 0.10, P less than 0.01, LVDd 57.1 +/- 7.9 mm vs 48.5 +/- 5.6 mm, P less than 0.01). The paced QRS duration correlated with LVEF (r = -0.61) and LVDd (r = 0.81). A paced QRS duration greater than or equal to 180 msec was sensitive and specific for a LVEF less than 0.5 (83.3% and 85.2%) and LVDd greater than or equal to 60 mm (100% and 81.4%). We conclude that patients with a prolonged paced QRS duration have more serious heart disease, and the paced QRS duration can be a useful indicator of impaired LV function.

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