52 Chronic Marijuana Use Presenting as Complete Heart Block.

Abstract

BackgroundMarijuana is the commonest illegal drug used in the USA. Legalizing its use as a medical drug is a long-standing debate opposed by the federal government. Marijuana consists of delta-9-tetrahydrocannibol (THC) as an active ingredient. The body has two target receptors for THC in the nervous system: CB(1) and CB(2). CB(1) is located centrally and in some peripheral neurons while CB(2) is located peripherally only. THC medicates its effects on the cardiovascular via the autonomic nervous system Acutely, it causes increase heart rate, precipitating angina in patient with coronary artery disease, atrial fibrillation, supine hypertension, and orthostatic hypotension. Chronic use results in an overstimulation of the parasympathetic nervous system, thus causing sinus bradycardia, and an episode of transient secondary heart block has being reported.Case ReportA 46-year-old black female presented with a syncopal episode lasting for less than a minute. Prior to the episode she felt dizzy and diaphoretic. The dizziness she noted started 1 week ago. The patient was otherwise well, with no history of diabetes, hypertension, or coronary artery disease. There was no medication at home and no recent travel. However, she smoked 2 "bags " of marijuana almost daily for 15 years. Her pulse was 35 b/min; other aspects of her physical examination were normal, except she complained of dizziness lying supine. ECG showed sinus bradycardia with 2:1 AV block. CXR was normal. Since the patient had symptomatic bradycardia a temporary transvenous pacing was put in place. An echo done subsequently was normal except for paradoxical septal movements secondary to pacemaker rhythm. Myocardial infraction was ruled out, and urine toxicology was negative; however, she was not tested for cannabis. Lyme titer and work-up for connective tissue diseases were also negative. Twenty-four hours after temporary wire placement ECG showed complete heart block. The patient was then observed for 72 hours for possible resolution of heart block; however, it persisted, and a permanent pacemaker was inserted.Teaching PointWith the push for medical marijuana use and high frequency among the teenage population any reportable side effects should be taken seriously. The person using marijuana and experiencing persistent dizziness should be encouraged to seek medical attention immediately.

Cannabis-Induced Third-Degree AV Block

“…To date, 10 reports have been published (PubMed search using the strategy: (“cannabis” OR “marijuana”) AND (“atrioventricular block” OR “av block” OR “heart block” OR “cardiac arrest” OR “bradycardia” OR “asystole” OR “sick sinus syndrome”) , see Table 1). The bradycardia was sinus arrest in six [20–25], second-degree AV block in two [2, 4], and third-degree AV block in two [3, 5]. With the exception of Menahem et al's case [21], all occurred in patients without any past cardiological history.…”

Mechanisms for the Risk of Acute Coronary Syndrome and Arrhythmia Associated With Phytogenic and Synthetic Cannabinoid Use

“…56,116 High doses of cannabinoids leading to vagal stimulation have the potential to provoke bradyarrhythmias including sinus arrest, syncope, atrioventricular block, and asystole as highlighted in several cases. [47][48][49][50][51][52][53] Postural hypotension and associated vasovagal reactions have also resulted in dizziness and syncope. 50,51,[53][54][55] Cannabinoid use is associated with modest increases in blood pressure and enhanced left ventricular systolic function, but this response is blunted in chronic users.…”

“…[47][48][49][50][51][52][53] Postural hypotension and associated vasovagal reactions have also resulted in dizziness and syncope. 50,51,[53][54][55] Cannabinoid use is associated with modest increases in blood pressure and enhanced left ventricular systolic function, but this response is blunted in chronic users. [18][19][20][135][136][137] Cannabinoid dysregulation of coronary circulation may be an important factor in the genesis of ACS and acute arrhythmias.…”

“…Several cases of ventricular arrhythmias, including atrioventricular block, ventricular tachycardia, and fibrillation, induced by exogenous cannabinoid use have been published. 21,22,47,48,50,53,71,[141][142][143][144][145]…”

Chronic marijuana consumption leading to reversible high-grade atrioventricular block in young male: A case report

“…There are several proposed mechanisms for cannabis induced tachyarrhythmia but how it causes bradyarrythmia is not very clear and mainly thought to be mediated by increased vagal tone. 2 Few cases of bradyarrythmia have been described previously [3][4][5][6][7][8][9][10][11][12][13] but reversible high grade atrio-ventricular (AV) block with electrophysiologic determination of site of conduction blockade is not reported to best of our knowledge. Our Patient presented with high grade AV block.…”