Atrioventricular blocks

Atrioventricular block in general is treated by implantation of an electrical pacemaker. A pharmacological alternative (although no longer used today) was atropine. However, atropine can be used for bridging the time between the onset of symptoms and the definitive implantation of a pacemaker. 

Adverse events need to be coded consistently with respect to letter case. Problems can occur when there is discordant coding using all capital letters, all lower-case letters, or combinations thereof, as computer software will interpret these capitalization variations as different events. Letter case sensitivity can be important when two or more words are used to describe an adverse event. For example, some databases utilizing the Medical Dictionary for Regulatory Activities (MedDRA) coding dictionary employ a coding system in which only the first letter of the first word of an adverse event is capitalized (e.g., Atrioventricular block complete ). Failing to adhere to uniform letter case conventions across the data can result in severe errors in data analysis. 

Bradycardia, decreased conduction (atrioventricular block at high doses), small negative inotropic action... 

Dolasetron Hypersensitivity to the drug or components of the product markedly prolonged QTc or atrioventricular block II to III patients receiving class I or III antiarrhythmic agents. 

Schnittger I, Appleton CP, Hatle LK, Popp RL. Diastolic mitral and tricuspid regurgitation by Doppler echocardiography in patients with atrioventricular block new insight into the mechanism of atrioventricular valve closure. J. Am. Coll. Cardiol. 1988 11 83-8. 

CCB non- Angina pectoris Atrioventricular block Constipation (verapamil)... 

Amiodarone is contraindicated in patients with sick sinus syndrome and may cause severe bradycardia and second-and third-degree atrioventricular block. Amiodarone crosses the placenta and will affect the fetus, as evidenced by bradycardia and thyroid abnormalities. The drug is secreted in breast milk. 

Cardiac toxicity is generally the result of drug-induced depression of cardiac conduction (e.g., atrioventricular block, intraventricular conduction block) and systemic vasodilation. These effects may progress to severe hypotension and cardiac arrest. 

Conduction delays, such as first-degree atrioventricular block... 

Flypertrophic obstructive cardiomyopathy, Wolff-Parkinson-White (WPW) syndrome, atrioventricular block and constrictive pericarditis. 

The most important toxic effects reported for calcium channel blockers are direct extensions of their therapeutic action. Excessive inhibition of calcium influx can cause serious cardiac depression, including cardiac arrest, bradycardia, atrioventricular block, and heart failure. These effects have been rare in clinical use. 

The pharmacokinetic properties of these drugs are set forth in Table 12-5. The choice of a particular calcium channel-blocking agent should be made with knowledge of its specific potential adverse effects as well as its pharmacologic properties. Nifedipine does not decrease atrioventricular conduction and therefore can be used more safely than verapamil or diltiazem in the presence of atrioventricular conduction abnormalities. A combination of verapamil or diltiazem with 3 blockers may produce atrioventricular block and depression of ventricular function. In the presence of overt heart failure, all calcium channel blockers can cause further worsening of heart failure as a result of their negative inotropic effect. Amlodipine, however, does not increase the mortality of patients with heart failure due to nonischemic left ventricular systolic dysfunction and can be used safely in these patients. 

Propranolol Nonselective competitive antagonist at adrenoceptors Decreased heart rate, cardiac output, and blood pressure decreases myocardial oxygen demand Prophylaxis of angina for other applications, see Chapters 10, 11, and 13 Oral and parenteral, 4-6 h duration of action Toxicity Asthma, atrioventricular block, acute heart failure, sedation Interactions Additive with all cardiac depressants... 

Verapamil, diltiazem Nonselective block of L-type calcium channels in vessels and heart Reduced vascular resistance, cardiac rate, and cardiac force results in decreased oxygen demand Prophylaxis of angina, hypertension, others Oral, IV, duration 4-8 h Toxicity Atrioventricular block, acute heart failure constipation, edema Interactions Additive with other cardiac depressants and hypotensive drugs... 

Severely depressed conduction may result in simple block, eg, atrioventricular nodal block or bundle branch block. Because parasympathetic control of atrioventricular conduction is significant, partial atrioventricular block is sometimes relieved by atropine. Another common abnormality of conduction is reentry (also known as "circus movement"), in which one impulse reenters and excites... 

Verapamil can induce atrioventricular block when used in large doses or in patients with atrioventricular nodal disease. This block can be treated with atropine and 3-receptor stimulants. 

Adenosine causes flushing in about 20% of patients and shortness of breath or chest burning (perhaps related to bronchospasm) in over 10%. Induction of high-grade atrioventricular block may occur but is very short-lived. Atrial fibrillation may occur. Less common toxicities include headache, hypotension, nausea, and paresthesias. 

Carvedilol Competitively blocks receptors (see Chapter 10) Slows heart rate reduces blood pressure poorly understood effects reduces heart failure mortality Chronic heart failure To slow progression reduce mortality in moderate and severe heart failure many other indications in Chapter 10. Oral duration 10-12 h Toxicity Bronchospasm, bradycardia, atrioventricular block, acute cardiac decompensation t see Chapter 10 for other toxicities and interactions... 

Rhabdomyolysis was associated with third-degree atrioventricular block in a patient taking atorvastatin with esomeprazole and clarithromycin. 

Brady WJ, Jr, Harrigan RA. Diagnosis and management of bradycardia and atrioventricular block associated with acute coronary ischemia. Emerg Med Clin North Am. 2001 19 371-384. 

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