Significance of the HV interval in 517 patients with chronic bifascicular block.

Abstract

SUMMARY In January 1975, we reported results of a prospective follow-up study (mean 538 ± 42 days) of 119 patients with chronic bifascicular block (BFB), and concluded that BFB patients with normal and prolonged HV (NHV and PHV) had a similar incidence of atrioventricular (AV) block and mortality. In this report, we update these findings in 517 patients with a follow-up of 21 days to 9.8 years (mean 3.4 ± 0.2 years). Three hundred nineteen patients (61%) had NHV and 198 (39%) had PHV (> 55 msec). The NHV and PHV groups were similar in regard to age (NHV vs PHV, 61 ± 1 vs 62 i 1 years) and sex (80% male, 20% female vs 82% male and 18% female). The following were more common (p < 0.05) in patients with PHV (percent of patients with finding in NHV vs PHV groups): angina (18% vs 27%), congestive failure (27% vs 42%), cardiomegaly (48% vs 66%), New York Heart Association functional class II-IV (34% vs 56%), premature ventricular complexes (20% vs 29%), and organic heart disease (OHD) (75% vs 85%). Spontaneous trifascicular block (TFB) developed in two patients (0.6%) with NHV and nine patients (4.5%) with PHV (p < 0.05). Cumulative 7-year incidence of TFB was 3% with NHV and 12% with PHV (p < 0.01). Seven-year cumulative cardiovascular mortality was 32% in NHV patients and 57% in PHV patients (p < 0.005).In conclusion, PHV in patients with chronic BFB was associated with a greater incidence and severity of OHD, and higher total and sudden death mortalities. The risk of spontaneous TFB was small in patients with either NHV or PHV, although it was significantly higher in the latter.THE CLINICAL SIGNIFICANCE of a prolonged HV interval in patients with chronic bifascicular block has been controversial. Scheinman et al.1' 2 and Narula et al.3 reported a higher incidence of atrioventricular (AV) block and a higher mortality in patients with bifascicular block and prolonged HV interval than in those with a normal HV interval. On the other hand, in an early analysis of our data, we reported no significant differences in the short-term follow-up regarding risk of AV block and mortality in 119 patients with bifascicular block, comparing patients with normal and prolonged HV intervals.4 McAnulty and co-workers confirmed our findings.'To resolve this controversy, we analyzed our experience in our series of patients with chronic bifascicular block. In this study, we examine and compare clinical, electrocardiographic and electrophysiologic variables in bifascicular block patients with normal and prolonged HV intervals. We also report prospective observations concerning life history of these patients to determine the prognostic significance of the HV interval.Our Circulation 64, No. 6, 1981No. 6, . 1265 believe that our data can be reconciled with previous data concerning the significance of the HV interval in patients with chronic bifascicular block. Materials and MethodsDefinitions are based on the recommendations of the Criteria Committee of the New York Heart Association.6 The criteria for electrocardiographic diagnosis of r...

Long‐term prognosis in patients with bifascicular block – the predictive value of noninvasive and invasive assessment

“…This observation is interesting since more prognostic information could be found in a simple clinical variable (NYHA classification) than in sophisticated and expensive investigations such as an invasive electrophysiological study. An annual all-cause mortality and sudden death of 4.7% and 2%, respectively, were observed in our study, which is similar to previous reports [3,5,21]. Some studies have shown that BFB per se is an independent risk factor of mortality [12][13][14], whereas others have reported that BFB merely reflects underlying heart disease, explaining the higher mortality rate in this population [3,6,7,15].…”

“…A mortality rate of 2-14% per year has been reported in an unselected BFB population, which is higher than in an age and sex matched population without BFB [3][4][5]11]. The mechanism behind the higher mortality has been the subject of investigation in previous studies with conflicting results.…”

Iroquois Homeodomain Transcription Factors in Heart Development and Function

“…On the other hand, Irx3 KO mice develop conduction disturbances characterized by ECG alterations (QRS prolongation and notched R waves), RBBB, prolonged HV durations, slowed conduction velocities in the Purkinje fibers of the VCS, and an abnormal activation pattern of the ventricles. These conduction defects occur commonly in humans, particularly in the setting of heart disease, [103][104][105] wherein ECG abnormalities correlate strongly with morbidity and mortality. 106,107 Indeed, left BBB by itself can induce cardiac hypertrophy and disease, whereas both the development of left BBB and RBBB are strongly linked to heart disease progression and poor disease outcomes, including sudden cardiac death.…”

Association of Prolonged QRS Duration With Death in a Clinical Trial of Pacemaker Therapy for Sinus Node Dysfunction

“…26,27 Interventricular and intraventricular conduction disturbances are the most common ECG pattern preceding the development of complete heart block, particularly in the presence of structural heart disease. 23,24,28 It is possible that cardiac pacing prevented some sudden deaths due to ventricular asystole among patients with prolonged QRSd in the present study; however, the majority of sudden deaths among patients with prolonged QRSd due to interventricular and intraventricular conduction disturbances and reduced left ventricular function are more likely due to ventricular tachycardia or ventricular fibrillation, 29,30 and permanent pacemakers have never been shown to reduce sudden death or prolong survival in this setting. 24,31 We observed that the risk of death increased linearly with baseline QRSd up to Ϸ120 ms and was level at higher values.…”

“…Some studies have shown that prolonged baseline QRSd is associated with sudden death, [1][2][3]23,24 and this risk appears to correlate with the degree of ventricular dyssynchrony in patients with systolic heart failure, 6 but the mechanisms of sudden death are probably diverse. Although prolonged QRSd correlates with total mortality risk in patients at high risk for sudden death who receive implantable cardioverter defibrillators, 25,26 it does not appear to predict the likelihood of appropriate therapies for spontaneous ventricular tachycardia or fibrillation.…”