Lethal Diseases of Heart
Heart Blocks 7/ 2005
Hi all. Yet another one, which occurred to me that I should do about two weeks ago, when a patient was doing some pretty strange things on the monitor. As usual, please remember that this is not meant to be an official reference, but is supposed to represent the information that a preceptor would pass on to a new orientee in the unit. Please get back to me if things aren’t clear, have been left out, or are just plain wrong, and I’ll fix them up right away. Thanks!
1- What is a heart block? 2- What exactly is being “blocked” in heart block? 2-1- The key idea: all of the time, some of the time, none of the time… 2-2- It can not be that simple… 3- Why do heart blocks happen? 4- What are the three types, or degrees of heart block? What is a “dropped beat”? 4-1- A normal rhythm for reference. 4-2- First degree heart block. 4-3- Second degree heart block. 4-3-1- Second degree, type 1: Wenckebach/ Mobitz 1 4-3-2- Second degree, type 2: Mobitz 2 4-4- How I tell them apart? 4-5- Third degree (complete) heart block. 5- A puzzler… 6- What is the treatment for heart block? 7- Where can I learn more about pacemakers?
1- What is a heart block?
Heart block is a kind of arrhythmia, usually caused by ischemia or an MI. There are three kinds, or degrees of heart block, and although sometimes people get confused about them, actually they’re pretty simple to understand.
2- What exactly is being “blocked” in heart block?
The signal from the SA node is trying to get to the AV node, and it’s being slowed down, or blocked altogether – it’s having a hard time getting through. The result is that the SA signal going through the atria makes a normal P wave, but if that signal doesn’t trigger a response from the AV node, no QRS gets produced – so you’ll see a P wave that isn’t followed by a QRS. The QRS represents ventricular depolarization –
Hi all. Yet another one, which occurred to me that I should do about two weeks ago, when a patient was doing some pretty strange things on the monitor. As usual, please remember that this is not meant to be an official reference, but is supposed to represent the information that a preceptor would pass on to a new orientee in the unit. Please get back to me if things aren’t clear, have been left out, or are just plain wrong, and I’ll fix them up right away. Thanks!
1- What is a heart block? 2- What exactly is being “blocked” in heart block? 2-1- The key idea: all of the time, some of the time, none of the time… 2-2- It can not be that simple… 3- Why do heart blocks happen? 4- What are the three types, or degrees of heart block? What is a “dropped beat”? 4-1- A normal rhythm for reference. 4-2- First degree heart block. 4-3- Second degree heart block. 4-3-1- Second degree, type 1: Wenckebach/ Mobitz 1 4-3-2- Second degree, type 2: Mobitz 2 4-4- How I tell them apart? 4-5- Third degree (complete) heart block. 5- A puzzler… 6- What is the treatment for heart block? 7- Where can I learn more about pacemakers?
1- What is a heart block?
Heart block is a kind of arrhythmia, usually caused by ischemia or an MI. There are three kinds, or degrees of heart block, and although sometimes people get confused about them, actually they’re pretty simple to understand.
2- What exactly is being “blocked” in heart block?
The signal from the SA node is trying to get to the AV node, and it’s being slowed down, or blocked altogether – it’s having a hard time getting through. The result is that the SA signal going through the atria makes a normal P wave, but if that signal doesn’t trigger a response from the AV node, no QRS gets produced – so you’ll see a P wave that isn’t followed by a QRS. The QRS represents ventricular depolarization –