What question did this study set out to answer?

To examine how various anti-arrhythmic agents affect the electrical frequency and power spectrum of established ventricular fibrillation over time.

July 1, 1990British Journal of PharmacologyOpen Access

Pharmacological analysis of established ventricular fibrillation

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Why the study?

Do anti-arrhythmic drugs alter the dominant frequency of established ventricular fibrillation in a greyhound model?

Population

Greyhounds anaesthetized with sodium pentobarbitone with established ventricular fibrillation induced by…

Comparison

Anti-arrhythmic drugs vs No drug

Design

Preclinical

Follow-up

3.3 minutes

Authors

ECEuan CarlisleWestern University JAJohn AllenVascular Medicine GKGeorge KernohanUniversity of Ulster

Discussion

Member takes

Implication

Caution against clinical use in human VF; leaves open calcium channel effects on VF frequency for prospective study.

Key Points

To examine how various anti-arrhythmic agents affect the electrical frequency and power spectrum of established ventricular fibrillation over time.
Induced ventricular fibrillation via endocardial electrical stimulation in greyhounds anesthetized with sodium pentobarbitone (35 mg kg⁻¹ i.v.).
Recorded dominant frequencies from lead II surface ECG and endocardial signals over 3.3 minutes in untreated controls and animals receiving lignocaine, propranolol, bretylium, or verapamil.
In untreated controls, dominant frequency fell in lead II from 9.9 ± 0.7 Hz initially to 4.0 ± 0.4 Hz at 3.3 minutes, while endocardial frequency remained elevated (10.7 ± 0.5 Hz).
Lignocaine significantly reduced dominant frequency in lead II (0–80 s) and endocardium (0–200 s), whereas propranolol and bretylium produced negligible alterations.
Verapamil prevented the lead II frequency decline after 80 s, maintaining significantly higher frequencies in lead II (14.7 ± 0.9 Hz) and endocardium (14.8 ± 0.9 Hz) at 3.3 minutes versus controls (P < 0.01).

Structured PICO

Do anti-arrhythmic drugs alter the dominant frequency of established ventricular fibrillation in a greyhound model?

Population

Greyhounds anaesthetized with sodium pentobarbitone (35 mg kg-1, i.v.) with established ventricular fibrillation induced by endocardial electrical stimulation

Intervention

Anti-arrhythmic drugs (lignocaine, propranolol, bretylium, verapamil)

Comparator

No drug

Outcome

Dominant frequency of ventricular fibrillation recorded from lead II and endocardiumsurrogate

Calcium channel blockade with verapamil prevents the rapid fall in dominant frequency during the initial stages of ventricular fibrillation, suggesting a role for intracellular calcium accumulation.

Cite This Study

Carlisle et al. (1990) studied this question.

synapsesocial.com/papers/6a76caaea7498e5110ae0f1f https://doi.org/10.1111/j.1476-5381.1990.tb15841.x

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