From the Guidelines
Patients with incomplete right bundle branch block (RBBB) generally do not require special anesthetic considerations as this condition rarely causes hemodynamic compromise. For these patients, proceed with standard anesthetic management while maintaining vigilant cardiac monitoring 1. During preoperative assessment, obtain a recent ECG to confirm the diagnosis and rule out progression to complete RBBB or other conduction abnormalities. Consider cardiology consultation only if the patient has symptoms like syncope, presyncope, or if there are other significant cardiac comorbidities. Some key points to consider in the management of these patients include:
- Maintaining normal electrolyte levels, particularly potassium and calcium, as imbalances can worsen conduction abnormalities 1
- Avoiding medications that significantly prolong the QT interval or depress cardiac conduction, such as high doses of propofol, halogenated inhalational agents, or certain antibiotics if possible
- Being aware that succinylcholine may cause transient potassium shifts
- Using standard ASA monitors for intraoperative monitoring, but considering arterial line placement for high-risk patients or major surgeries Incomplete RBBB represents a partial delay in right ventricular depolarization but typically doesn't affect cardiac output or hemodynamic stability, unlike complete RBBB which may progress to complete heart block in some circumstances 1. It's also important to note that the 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay provides definitions and management strategies for various conduction abnormalities, including RBBB 1. However, the most recent and highest quality study, which is the 2019 guideline, should be prioritized when making management decisions 1.
From the Research
Incomplete Right Bundle Branch Block Considerations
- Incomplete right bundle branch block (IRBBB) is a common electrocardiogram (ECG) finding that can express both benign and pathological patterns 2.
- IRBBB is more frequent in men and athletes, and usually does not require further evaluation unless abnormalities are found on the clinical exam 2.
- The RSR’ pattern and a QRS width below 100 ms define the crista supraventricularis (CSV) pattern, which might result from posterior apex deviation, subpulmonic area delay, or late CSV activation 2.
Anesthesia Considerations
- There is no direct evidence in the provided studies regarding anesthesia considerations for patients with IRBBB.
- However, it is essential to differentiate IRBBB from pathological patterns such as type-2 Brugada ECG pattern, right ventricular enlargement, arrhythmogenic right ventricular cardiomyopathy, ventricular preexcitation—Wolf-Parkinson-White syndrome, and hyperkalemia 2.
- Clinicians should be familiar with IRBBB and its potential implications, as it is not always a benign condition 2, 3, 4.
Diagnostic Challenges
- The diagnosis of IRBBB can be challenging, and examiners should be alert to the splitting of the second heart sound, as RBBB is a common finding in ostium secundum atrial septal defect 2.
- An rSr' pattern with QRS duration of less than 0.12 s in the right precordial leads can be due to IRBBB or a normal electrophysiological variant 3.
- Certain ECG features, such as diminution of the S wave depth, inversion of ratio of the S wave depth to SV1 > SV2, slurring of the downstroke or upstroke of the S wave, and prolongation of the QRS duration, can help distinguish between IRBBB and a normal variant 3.