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Congenital complete heart block in structurally normal heart--a study of 44 cases
A Saxena1, S Shrivastava, V Dev
1Department of Cardiology, All India Institute of Medical Sciences, New Delhi.
Insights
Congenital complete heart block in children can present with symptoms like syncope. A slow heart rate, wide QRS escape rhythm, and pauses on ambulatory ECG monitoring indicate high risk, potentially warranting a pacemaker.
Area of Science:
- Pediatric Cardiology
- Electrophysiology
- Congenital Heart Disease
Background:
- Congenital complete heart block (CCHB) is a rare condition.
- Patients with CCHB and structurally normal hearts can be asymptomatic or symptomatic with low cerebral perfusion.
- Identifying risk factors for adverse events is crucial for management.
Purpose of the Study:
- To analyze clinical and electrophysiological data of patients with CCHB and structurally normal hearts.
- To identify predictors of symptoms and high-risk events in this population.
- To evaluate the utility of electrophysiological studies in differentiating symptomatic and asymptomatic patients.
Main Methods:
- Analysis of data from 44 patients with CCHB and structurally normal hearts.
- Classification into asymptomatic (Group I, n=31) and symptomatic (Group II, n=13) groups based on symptoms of low cerebral perfusion.
- Comparison of ventricular rates, QRS duration, pauses on ambulatory ECG monitoring, and electrophysiological study findings between groups.
Main Results:
- Symptomatic patients (Group II) had significantly lower ventricular rates (46.5 bpm) compared to asymptomatic patients (Group I, 56.7 bpm).
- Wide QRS escape rhythm and pauses (>3 seconds) were more frequent in the symptomatic group, though not always statistically significant.
- Electrophysiological studies did not differentiate the groups, showing suprahisian block in all evaluated patients.
Conclusions:
- Persistently slow ventricular rate (<50 bpm), wide QRS escape rhythm, and prolonged pauses suggest high risk in CCHB patients.
- These findings may justify permanent pacemaker implantation even in asymptomatic individuals.
- Electrophysiological studies may not be essential for risk stratification in this specific CCHB population.
Abstract:
Data of 44 patients with congenital complete heart block and structurally normal heart have been analysed. Thirty one patients were asymptomatic (group I) and 13 patients had symptoms of low cerebral perfusion like syncope, near syncope or convulsions (group II). A ventricular rate on surface ECG was found to be significantly lower in the symptomatic group (56.7 +/- 13.2 beats per minute, bpm, in group I and 46.5 +/- 6.0 bpm in group II). Similarly wide QRS escape rhythm of greater than 0.10 seconds was more often seen in group II (2/13) as compared to group I (2/31) though the difference did not reach statistical significance. Presence of pauses of more than 3.0 seconds on ambulatory ECG monitoring were infrequent in both the groups (group I 1/7, group II 2/7), however more often seen in group II. Electrophysiological studies carried out in 11 patients were not helpful in differentiating the two groups and all the patients including two with a wide QRS escape rhythm on surface ECG showed suprahisian level of block. The corrected junctional recovery time in two groups did not show any statistical difference. A persistently slow ventricular rate of less than 50 bpm during waking hours, wide QRS escape rhythm and pauses of greater than 3 seconds on ambulatory monitoring are suggestive of high risk to the patient and may justify implantation of permanent pacemaker even in asymptomatic patients.