Page 1 of 5

British Journal of Healthcare and Medical Research - Vol. 12, No. 02

Publication Date: April 25, 2025

DOI:10.14738/bjhmr.1202.18400.

Hermiz, J., Mittal, V., Raj, K., Bhagat, U., & Gahona, C. C. T. (2025). Complete Heart Block Induced by Hyperemesis: Integrating the

Vagal Score to Guide Management and Avoid Invasive Interventions. British Journal of Healthcare and Medical Research, Vol -

12(02). 53-57.

Services for Science and Education – United Kingdom

Complete Heart Block Induced by Hyperemesis: Integrating the

Vagal Score to Guide Management and Avoid Invasive

Interventions

Joshua Hermiz

Department of Internal Medicine and Cardiology

Trinity Health Oakland Hospital-Pontiac, Michigan USA

Vivek Mittal

Department of Internal Medicine and Cardiology

Trinity Health Oakland Hospital-Pontiac, Michigan USA

Kevin Raj

Department of Cardiology

University of California Riverside-San Bernardino, California USA

Umesh Bhagat

Department of Internal Medicine

Cleveland Clinic Hospital-Cleveland, Ohio USA

Christian C. Toquica Gahona

Department of Cardiology

Trinity Health Oakland Hospital-Pontiac, Michigan USA

ABSTRACT

Complete heart block (CHB) represents the complete absence of atrioventricular

(AV) conduction between the atria and ventricles, preventing the sinoatrial node

from regulating heart rate and cardiac output through communication with the AV

node. Although standard treatment involves permanent pacemaker implantation,

it is crucial to identify reversible causes such as electrolyte imbalances or vagal- mediated mechanisms, as it may allow for alternative, non-invasive management.

This case report discusses a rare instance of hyperemesis-induced CHB and utilizes

the "vagal score" via ECG-based assessments to determine approach to

management, ultimately identifying reversible etiologies and preventing

unnecessary invasive interventions such as permanent pacemaker placement.

Keywords: Third-degree atrioventricular block, hyperemesis, vagal score, reversible

heart block, hypokalemia

INTRODUCTION

Atrioventricular block (AVB) is a disruption of the electrical conduction between the sinoatrial

(SA) node and ventricles, passing through the AV node. In a third-degree AVB, known as

complete heart block (CHB), communication between the atria and ventricles is lost. Without

effective conduction through the AV node, the SA node can no longer regulate heart rate, leading

Page 2 of 5

54

British Journal of Healthcare and Medical Research (BJHMR) Vol 12, Issue 02, April-2025

Services for Science and Education – United Kingdom

to reduced cardiac output due to uncoordinated atrial and ventricular contractions [1]. AVB is

typically treated with a permanent pacemaker and can be life-threatening if left untreated [2].

CHB is sometimes reversible in settings such as acute MI by restoring coronary perfusion and

in conditions such as Lyme disease [3].

Lyme carditis (LC) is an early manifestation of Lyme disease and one of the more notable causes

of reversible CHB, which typically resolves with antibiotic therapy [4]. Identifying LC as the

etiology of AVB can prevent inappropriate placement of a permanent pacemaker in a

potentially reversible condition.

Understanding AVB is essential, and advances in diagnostic modalities, particularly enhanced

electrocardiographic (ECG) monitoring, have elucidated the phenomenon of paroxysmal AVB,

which often precedes permanent AVB [5]. This case highlights the importance of understanding

vagally-mediated CHB which is reversible with proper identification and management. As a

result, a 'vagal score' has been introduced to assess whether an AVB is vagal-mediated by

analyzing the patient's ECG [6].

In this case, we present a 43-year-old female who experienced third-degree AVB precipitated

by hyperemesis.

CASE REPORT

A 43-year-old female with no past medical or surgical history presented to the Emergency

Department with abdominal pain, nausea, and vomiting for one week. She reported constant

sharp mid-abdominal pain radiating to the right flank and back that developed abruptly within

minutes. Her pain was accompanied by nausea and recurrent vomiting, described as yellow- tinged. CT of the abdomen/pelvis showed a slightly delayed right renal nephrogram, indicative

of a recently passed renal calculus without hydronephrosis. She was diagnosed with renal colic

and discharged home with antiemetics.

Two days later, she returned with ongoing nausea and vomiting, but now included a headache

and lightheadedness, but no fever or chills. She was hypotensive and bradycardic with dry

mucous membranes and delayed capillary refill on physical exam. Initial ECG showed sinus

bradycardia with second-degree AVB (Mobitz II), U waves, and heart rate of 39 BPM.

Laboratory studies showed WBC 18.4 and negative beta-hCG. Urinalysis was negative. Serum

potassium reached a nadir of 3.1 mmol/L which was repleted with potassium-chloride and

magnesium. Additional therapy including fluids, analgesics, and antiemetics were provided.

After potassium replacement, repeat ECG showed first-degree AV block and sinus bradycardia

with heart rate of 50 BPM. During her admission, continuous cardiac monitoring revealed

intermittent episodes of CHB with atrio-ventricular dissociation [Figure 1]. Further evaluation

by cardiology consisted of utilization and application of the vagal score, in which she achieved

an ECG-index of 4 [table 1], suggesting her CHB is vagal-mediated. Therefore, conservative

management was recommended prior to considering pacemaker implantation. Serial ECGs

demonstrated resolution of the CHB after electrolyte correction and volume repletion.

Application of the vagal score eliminated the need for permanent pacemaker placement.

Page 3 of 5

55

Hermiz, J., Mittal, V., Raj, K., Bhagat, U., & Gahona, C. C. T. (2025). Complete Heart Block Induced by Hyperemesis: Integrating the Vagal Score to

Guide Management and Avoid Invasive Interventions. British Journal of Healthcare and Medical Research, Vol - 12(02). 53-57.

URL: http://dx.doi.org/10.14738/bjhmr.1202.18400.

Table 1: A vagal score (VS) ≥3 strongly suggests a vagally mediated block [6]. Reflex

prodromal features like flushing, dizziness, and nausea may offer diagnostic clues but

are not consistently present. Similarly, a history of syncope may or may not be evident.

ECG Index/Criteria: Score:

1. No AVB or intraventricular conduction disturbance on baseline ECG +1

0. PR prolongation immediately before P-AVB +1

0. Sinus slowing immediately before P-AVB +1

0. Initiation of P-AVB by PP prolongation +1

0. Sinus slowing during ventricular asystole +1

0. Resumption of AV conduction with PP shortening +1

0. Initiation of P-AVB by a premature beat -1

0. Resumption of AV conduction by an escape beat -1

Vagal Score: adapted from source [6]

Figure 1: 12-lead-EKG showing complete atrio-ventricular dissociation. P-waves marked by red

arrows, QRS marked by blue arrows. Atrial heart rate around 60 beats-per-minute and

ventricular heart rate of 42 beats per minute.

DISCUSSION

This case demonstrates the critical interaction between hypokalemia, volume depletion, and

vagal stimulation leading to CHB. Therefore, it is crucial that clinicians conduct a methodical

investigation to identify and address potential reversible causes of AVB. Recognition of

reversible CHB is pivotal in avoiding unnecessary interventions, such as pacemaker

implantation. Therefore, the introduction of a "vagal score" was developed, as proposed by

Komatsu et al., which serves as a useful diagnostic tool in distinguishing vagally-mediated AVB

from intrinsic conduction system disease. Points are assigned or deducted according to specific

criteria [table 1]. Our patient received a vagal score of 4, indicating a vagally-mediated

block. Despite its clinical value, this scoring system remains underutilized and there are no

published cases discussing its application or accuracy in clinical practice. In this patient, the

application of the vagal score allowed for a targeted, conservative approach to management,