Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal...
-
date post
15-Jan-2016 -
Category
Documents
-
view
212 -
download
0
Transcript of Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal...
![Page 1: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/1.jpg)
Cardiac Arrhythmias II: Tachyarrhythmias
Michael H. Lehmann, M.D.
Clinical Professor of Internal Medicine
Director, Electrocardiography Laboratory
![Page 2: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/2.jpg)
Supraventricular Tachycardias
(Supraventricular - a rhythm process in which the ventricles are activated from the atria or AV node/His bundle region)
![Page 3: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/3.jpg)
Supraventricular Tachycardia (SVT) Terminology
• QRS typically narrow (in absence of bundle branch block); thus, also termed narrow QRS tachycardia
• Usually paroxysmal, i.e, starting and stopping abruptly; in which case, called PSVT
•“Paroxysmal Atrial Tachycardia (PAT)” - the older term for PSVT - is misleading and should be abandoned
![Page 4: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/4.jpg)
AV Junctional Reentrant Tachycardias(typically incorporate AV nodal tissue)
![Page 5: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/5.jpg)
UnidirectionalBlock
Recovery of Excitability & Reentry
BidirectionalConduction
Mechanism of Reentry
![Page 6: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/6.jpg)
AV Nodal Reentrant Tachycardia
![Page 7: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/7.jpg)
AV Nodal Reentrant Tachycardia Circuit
F = fast AV nodal pathway
S = slow AV nodal pathway
(His Bundle)
During sinus rhythm, impulses conduct preferentiallyvia the fast pathway
![Page 8: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/8.jpg)
Initiation of AV Nodal Reentrant Tachycardia
PAC = premature atrial complex (beat)
PAC
PAC
![Page 9: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/9.jpg)
Sustainment of AV Nodal Reentrant Tachycardia
Rate 150-250beats per min
P waves generatedretrogradely(AV node atria) andfall within orat tail of QRS
![Page 10: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/10.jpg)
P P P P
Sustained AV Nodal Reentrant Tachycardia
Note fixed, short RP interval mimicking r’ deflection of QRS
V1
![Page 11: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/11.jpg)
Orthodromic AV Reentrant Tachycardia
AP
Anterogadeconduction via normal pathwayRetrograde
conductionvia accessorypathway (AP)
![Page 12: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/12.jpg)
Initiation of Orthodromic AV ReentrantTachycardia
AVN
Ventricles
Atria
AP
PAC = premature atrial complex (beat)
PAC
![Page 13: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/13.jpg)
Sustainment of Orthodromic AV Reciprocating Tachycardia
Atria
AP
AVN
Ventricles
Retrograde P’s fall in the ST segmentwith fixed, short RP
Rate 150-250beats per min
![Page 14: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/14.jpg)
Accessory Pathway with Ventricular Preexcitation(Wolff-Parkinson-White Syndrome)
Fusion activation of the ventricles
“Delta” Wave
APPR < .12 s
QRS .12 s
Sinusbeat
Hybrid QRS shape
![Page 15: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/15.jpg)
Varying Degrees of Ventricular Preexcitation
![Page 16: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/16.jpg)
Normal synchronousoverlapping activationof both ventricles:
On timeAsynchronous
scenario I:
Late
Head startOn time(or late)
Asynchronous scenario II:
QRS
Narrow
Wide
Wide
QRS Width: Synchronous vs. Asynchronous Ventricular Activation
![Page 17: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/17.jpg)
Intermittent Accessory Pathway Conduction
NormalConduction
V Preex V Preex
Note “all-or-none” nature of AP conduction
![Page 18: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/18.jpg)
Orthodromic AV Reentrant Tachycardia
NSR with V Preex
SVT:V Preex gone
Note retrograde P wavesin the ST segment
![Page 19: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/19.jpg)
Concealed Accessory Pathway
No Delta wave during NSR(but AP capable of retrogradeconduction)
Sinusbeat
![Page 20: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/20.jpg)
Summary of AV Junctional Reentrant Tachycardias
• Reentrant circuit incorporates AV nodal tissue
• P waves generated retrogradely over a fast pathway
• Short, fixed RP interval
![Page 21: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/21.jpg)
Clinical Significance of AV Junctional Reentrant Tachycardias
• Rarely life-threatening
• However, may produce serious symptoms (dizziness or syncope [fainting])
• Can be very disruptive to quality of life
• Involvement of an accessory pathway can carry extra risks
![Page 22: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/22.jpg)
Atrial Tachyarrhythmias
![Page 23: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/23.jpg)
Sinus Tachycardia (100 to 180+ beats/min)
• P waves oriented normally• PR usually shorter than at rest
![Page 24: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/24.jpg)
Causes of Sinus Tachycardia
• Hypovolemia ( blood loss, dehydration)
• Fever
• Respiratory distress
• Heart failure
• Hyperthyroidism
• Certain drugs (e.g., bronchodilators)
• Physiologic states (exercise, excitement, etc)
![Page 25: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/25.jpg)
V5
P P P P’ P
Timing of Expected P
Premature Atrial Complex (PAC)
Non-Compensatory Pause
![Page 26: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/26.jpg)
Premature Atrial Complex (PAC): Alternative Terminology
• Premature atrial contraction
• Atrial extrasystole
• Atrial premature beat
• Atrial ectopic beat
• Atrial premature depolarization
![Page 27: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/27.jpg)
PACs: Bigeminal Pattern
P P’ P P’ P P’
• Note deformation of T wave by the PAC• “Regularly Irregular” Rhythm
![Page 28: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/28.jpg)
PACs with Conduction Delay/Block
Physiologic AV Block
PhysiologicAV Delay
Recovered AV Conduction
P
P
P
P’
P’
P’
![Page 29: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/29.jpg)
PAC with “Aberrant Conduction”(Physiologic Delay in the His Purkinje System)
V1
P P P’ P
RBBB
![Page 30: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/30.jpg)
V1
PACs with Aberrant Conduction(Physiologic RBBB and LBBB)
RBBB LBBB Normalconduction
![Page 31: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/31.jpg)
PACs with Physiologic LBBB and His-Purkinje System Block
V1
Non-conductedPAC
![Page 32: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/32.jpg)
Non-Conducted PAC
P P PP’
V5
V1
Note deformation of T wave by the PAC
![Page 33: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/33.jpg)
Bigeminal/Blocked PACs Mimicking Sinus Bradycardia
V1
Only the 4th bigeminal PAC conducts
![Page 34: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/34.jpg)
Clinical Significance PAC’s
• Common in the general population
• May be associated with heart disease
• Can be a precursor to atrial tachyarrhythmias
![Page 35: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/35.jpg)
• RP intervals can be variable • RP often > PR• (Example slower than more common rate mof 150-250 beats per min)
Atrial Tachycardia
V1
Differs fromAV nodal or AV reentrantSVT
![Page 36: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/36.jpg)
Clinical Significance of Atrial Tachycardia
• Similar to sequela of AV junctional reentrant tachycardias
• Must be differentiated from them diagnostically
![Page 37: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/37.jpg)
Atrial Flutter (“Typical,” Counterclockwise)
Reentrant mechanism
![Page 38: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/38.jpg)
II
V1
Atrial Flutter
4:1 2:1
Classicinverted “sawtooth”flutter wavesat 300 min-1 (best seen inII, III and AVF)
Note variableventricularresponse
![Page 39: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/39.jpg)
Atrial Flutter
2:1Conduction(common)
2:1 & 3:2Conduction
1:1Conduction(rare but dangerous)
V. rate 140-160beats/min
![Page 40: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/40.jpg)
Atrial Fibrillation
Focal firingormultiplewavelets Chaotic, rapid
atrial rate at400-600beats per min
![Page 41: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/41.jpg)
V5
Atrial Fibrillation
• Rapid, undulating baseline (best seen in V1)• Most impulses block in AV node Erratic conduction
V1
![Page 42: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/42.jpg)
Atrial Fibrillation: Characteristic “Irregularly Irregular” Ventricular Response
II
![Page 43: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/43.jpg)
Atrial Fibrillation with Rapid Ventricular Response
II
Irregularity may be subtle
![Page 44: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/44.jpg)
Atrial Fibrillation: Autonomic Modulation of Ventricular Response
Baseline
Immediately after exercise
![Page 45: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/45.jpg)
Clinical Significance of Atrial Flutter and Fibrillation
• Causes – Usually occur in setting of heart disease;
but sometimes see “lone “ atrial fibrillation– Hyperthyroidism (atrial fibrillation)
• May acutely precipitate myocardial ischemia or heart failure
• Chronic uncontolled rates may induce cardiomyopathy and heart failure
• Both can predispose to thromboembolic stroke, etc
![Page 46: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/46.jpg)
Varying Degrees of Ventricular Preexcitation
![Page 47: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/47.jpg)
Atrial Fibrillation with Rapid Conduction Via Accessory Pathway
![Page 48: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/48.jpg)
Atrial Fibrillation with Third Degree AV Block
V1
V5
Regular ventricular rate reflects dissociated slow junctional escape rhythm
![Page 49: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/49.jpg)
Regular Narrow QRS Tachycardias
![Page 50: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/50.jpg)
Differential Diagnosis of Regular Narrow QRS (Supraventricular) Tachycardia
• Reentrant SVT incorporating AV nodal tissue– AV nodal reentrant tachycardia– Orthodromic AV reentrant tachycardia
• SVT mechanism confined to the atria– Sinus tachycardia– Atrial flutter– Other regular atrial tachycardias
• Short-RP favors AV node-dependent reentrant SVT
![Page 51: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/51.jpg)
Determining AV Nodal Participation in SVT by Transiently Depressing AV Nodal Conduction
• Vagotonic Maneuvers– Carotid sinus massage– Valsalva maneuver (bearing down)– Facial ice pack (“diving reflex;” for kids)
• Adenosine (6-12 mg I.V.)
• If SVT “breaks,” a reentrant mechanism involving the AV node is likely
• If atrial rate unchanged, but ventricular rate slows (#P’s > #QRS’s), SVT is atrial in origin
![Page 52: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/52.jpg)
SVT Responses to AV Nodal Depressant Maneuvers
• SVT termination– AV nodal reentrant tachycardia– Orthodromic AV reentrant tachycardia
• No SVT termination (despite maximal attempts)– Sinus tachycardia– Atrial flutter or fibrillation– Most atrial tachycardias (a minority are “adenosine-
sensitive”)
![Page 53: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/53.jpg)
Carotid Sinus Massage
Stimulation of carotid sinus triggers baroreceptorreflex and increased vagaltone, affectingSA and AV nodes
![Page 54: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/54.jpg)
Termination of SVT by Vagotonic Maneuver (Carotid Sinus Massage)
![Page 55: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/55.jpg)
SVT
Carotid Sinus Massage
![Page 56: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/56.jpg)
SVT
Adenosine 6 mg
P P P P
![Page 57: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/57.jpg)
Ventricular Tachyarrhythmias
![Page 58: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/58.jpg)
Premature Ventricular Complex (PVC): Alternative Terminology
• Premature ventricular contraction
• Ventricular extrasystole
• Ventricular premature beat
• Ventricular ectopic beat
• Ventricular premature depolarization
![Page 59: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/59.jpg)
Premature Ventricular Complex (PVC)
Compensatory Pause
![Page 60: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/60.jpg)
Normal synchronousoverlapping activationof both ventricles:
On timeAsynchronous
scenario I:
Late
Head startOn time(or late)
Asynchronous scenario II:
QRS
Narrow
Wide
Wide
QRS Width: Synchronous vs. Asynchronous Ventricular Activation
![Page 61: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/61.jpg)
PVCs: Bigeminal Pattern
“Regularly Irregular” Rhythm
![Page 62: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/62.jpg)
Ectopic ventricular activation
Normal ventricular activation
Fusionbeat
Accelerated Idioventricular Rhythm ( Ventricular Escape Rate, but 100 bpm)
Sinus acceleration
![Page 63: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/63.jpg)
SANode
Ventricular Focus
ATRIA AND VENTRICLESACT INDEPENDENTLY
AV Dissociation
![Page 64: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/64.jpg)
V1
Ventricular Tachycardia (VT)
• Rates range from 100-250 beats/min• Non-sustained or sustained • P waves often dissociated (as seen here)
![Page 65: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/65.jpg)
Ladder Diagram of AV Dissociation During Ventricular Tachycardia
Slower atrial rate
Faster ventricular rate
Impulses invade the AV node retrogradely and anterogradely,creating physiologic “interference” and block. Under the right conditions, some anterograde impulses may slip through.
This phenomenon is not equivalent to third degree AV block
![Page 66: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/66.jpg)
Ladder Diagram of AV Dissociation During Third Degree AV Block
Faster atrial rate
Slower ventricular (escape) rhythm
Note that impulses block anterogradely and retrogradelywithin the AV conduction system
![Page 67: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/67.jpg)
Monomorphic VT
![Page 68: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/68.jpg)
V1
Polymorphic VT
![Page 69: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/69.jpg)
Causes of PVC’s and VT
• PVC’s are fairly common in normals but are also seen in the setting of heart disease
• Monomorphic VT often implies heart disease, but can sometimes be seen in structurally “normal” hearts
• Polymorphic VT can result from myoardial ischemia or conditions that prolong ventricular repolarization
• Electrolyte derangements, hypoxemia and drug toxicity can cause PVC’s and VT
![Page 70: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/70.jpg)
MI Scar-Related Sustained Monomorphic VT Circuit
![Page 71: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/71.jpg)
“Torsade de Pointes”(Polymorphic VT Associated with Prolonged Repolarization)
![Page 72: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/72.jpg)
Clinical Significance of PVC’s and VT
• Can be a tip-off to underlying cardiac, respiratory or metabolic disorder
• VT may (but need not invariably) lead to hemodynamic collapse or more life-threatening ventricular tachyarrhythmias, increasing the risk of cardiac arrest
![Page 73: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/73.jpg)
Ventricular Flutter
• VT 250 beats/min, without clear isoelectric line• Note “sine wave”-like appearance
![Page 74: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/74.jpg)
Ventricular Fibrillation (VF)
• Totally chaotic rapid ventricular rhythm• Often precipitated by VT• Fatal unless promptly terminated (DC shock)
![Page 75: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/75.jpg)
Sustained VT: Degeneration to VF
![Page 76: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/76.jpg)
Atrial Fibrillation with Rapid Conduction Via Accessory Pathway: Degeneration to VF
![Page 77: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/77.jpg)
Diagnosing Regular Wide QRS Tachycardia
![Page 78: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/78.jpg)
Regular Wide QRS Tachycardia: VT or SVT with Aberrant Conduction?
V1
![Page 79: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/79.jpg)
Sustained Aberrant Conduction
V1
![Page 80: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/80.jpg)
Clinical Clues to Basis for Regular Wide QRS Tachycardia
• REMEMBER: VT does not invariably cause hemodynamic collapse; patients may be conscious and stable
• History of heart disease, especially prior myocardial infarction, suggests VT
• Occurrence in a young patient with no known heart disease suggests SVT
• 12-lead EKG (if patient stable) should be obtained
![Page 81: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/81.jpg)
Regular Wide QRS Tachycardia: VT or SVT with Aberrant Conduction?
![Page 82: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/82.jpg)
More R-Waves Than P-Waves Implies VT!
II
![Page 83: Cardiac Arrhythmias II: Tachyarrhythmias Michael H. Lehmann, M.D. Clinical Professor of Internal Medicine Director, Electrocardiography Laboratory.](https://reader035.fdocuments.us/reader035/viewer/2022070412/56649d795503460f94a5cc72/html5/thumbnails/83.jpg)
Artifact Mimicking “Ventricular Tachycardia”
Artifact precedes“VT”
QRS complexes “march through”the pseudo-tachyarrhythmia