From the Guidelines
Ventricular standstill is a life-threatening cardiac emergency where the ventricles of the heart completely stop contracting, resulting in no cardiac output, and requires immediate intervention with cardiopulmonary resuscitation (CPR) and advanced cardiac life support measures. This condition appears on an electrocardiogram (ECG) as P waves (representing normal atrial activity) with no corresponding QRS complexes, indicating the absence of ventricular electrical activity. The management of ventricular standstill involves:
- Immediate initiation of CPR
- Administration of epinephrine (1 mg IV every 3-5 minutes)
- Transcutaneous pacing
- Urgent placement of a temporary transvenous pacemaker, followed by permanent pacemaker implantation, as definitive management. Ventricular standstill differs from asystole in that atrial electrical activity continues, but the ventricles fail to respond. Common causes include severe heart block, myocardial infarction, electrolyte disturbances (particularly hyperkalemia), drug toxicity (especially from digoxin, beta-blockers, or calcium channel blockers), and end-stage heart disease. Without immediate intervention, ventricular standstill is rapidly fatal as it results in complete cessation of blood flow to vital organs, with patients found to be in true cardiac standstill on bedside cardiac ultrasonography (BCU) having a nearly 100% mortality rate 1. The use of BCU may be helpful in guiding further resuscitative efforts during asystole, as it can detect whether true cardiac contractility is occurring 1. However, in pediatric patients, BCU alone is insufficient to diagnose irreversible pulseless cardiac activity in cardiac arrest, and other factors such as the underlying cause of the arrest and the potential for recovery should be considered 1. In general, the prognosis for non-VF/VT rhythms, including ventricular standstill, is less favorable than for VF/VT rhythms, with an overall survival rate of about 10-15% of the survival rate with VF/VT rhythms 1. Therefore, immediate and aggressive treatment is necessary to improve outcomes in patients with ventricular standstill, with a focus on high-quality CPR, prompt identification and treatment of reversible causes, and timely placement of a pacemaker if necessary.
From the Research
Definition of Ventricular Standstill
- Ventricular standstill is an electrophysiologic phenomenon characterized by the absence of ventricular activity or contraction 2.
- It is the result of the lack of impulse formation in ventricles (absence of idioventricular automaticity) or the failure of impulse transmission to ventricles (conduction disturbance) 2.
Characteristics and Consequences
- Ventricular standstill is a rare cardiac event associated with a high mortality and is considered a ventricular fibrillation equivalent 3.
- The longer the duration, the poorer the prognosis 3.
- It can manifest as syncope, and in some cases, the patient may be asymptomatic 4.
- Ventricular standstill can be caused by profound vagal tone, and treatment with a permanent pacemaker may be necessary 4.
Diagnosis and Treatment
- Ventricular standstill requires prompt diagnosis and intervention, especially in patients with structural heart disease 5.
- Clinicians should recognize ventricular standstill as a complication of cardiac revascularization and be cognizant of asymptomatic cases necessitating intervention 5.
- Treatment should be focused on resolving the precipitating factors, and swift and sound clinical judgment is required 2.
- In some cases, pacemaker implantation may be necessary to facilitate good outcomes 5.
Comparison with Other Cardiac Conditions
- Ventricular standstill is different from other cardiac conditions such as ventricular fibrillation and asystole, and its treatment may vary depending on the underlying cause 6.
- The use of vasopressin during cardiopulmonary resuscitation and vasodilatory shock may be beneficial in some cases, but its effectiveness in treating ventricular standstill is unknown 6.