Pacemaker components include the battery, pacing impedance, pulse generator, and modes and mode switching. Pacing impedance refers to opposition to current flow and varies between 250-1200 ohms. The pulse generator includes output, sensing, and timing circuits. Capture threshold is the minimum energy for depolarization. Pacemaker follow up includes electrical testing and management of complications like pocket hematomas, infections, and device malfunctions such as failure to capture or output.
rotablation is procedure used in complex pci with heavily calcified lesion for adequate expansion of stent.if used in indicated case and well aware of contraindication is necessary for achieving good results.
rotablation is procedure used in complex pci with heavily calcified lesion for adequate expansion of stent.if used in indicated case and well aware of contraindication is necessary for achieving good results.
This is a comprehensive description of coronay lesion assessment from routinely used angiography to advanced imaging modalities like IVUS/OCT including their functional significance by FFR
Diagnostic catheters for coronary angiography Aswin Rm
Overview of diagnostic catheters used in coronary angiography
Guide catheters not included
History of coronary catheters
Radial techniques and catheters
Although the risks of coronary angiography have declined over the years by increased clinical experience and advanced technologies, it still requires attention, knowledge and experience due to being an interventional diagnostic method. A safe coronary angiography begins with the selection of the appropriate catheter for the anatomical structure of the patient and the evaluation of the pressure when the catheter is placed in the coronary ostium. Coronary pressure waves are complementary requirements of angiography. The recognition, evaluation and precautions to be taken for abnormal pressure waves directly affect the mortality of the patient. One of the first clues to the presence of stenosis in the left main coronary artery (LMCA) is abnormal changes in pressure when the catheter is seated in the ostial LMCA. This often occurs as a “ventricularization” or “damping”. For decades, ventricularization was mostly experienced as a stenosis by invasive cardiologists [1]. Recognition of abnormal changes in pressure and precautions to be taken prevent catastrophic outcomes in patients
https://crimsonpublishers.com/ojchd/fulltext/OJCHD.000518.pdf
For more open access journals in Crimson Publishers
please click on https://crimsonpublishers.com/
For more articles in open journal of Cardiology & Heart Diseases
please click on https://crimsonpublishers.com/ojchd/
Based on the principle that the distal coronary pressure measured during vasodilation is directly proportional to maximum vasodilated perfusion.
FFR is defined as the ratio of maximum blood flow in a stenotic artery to maximum blood flow in the same artery if there were no stenosis.
FFR is simply calculated as a ratio of mean pressure distal to a stenosis (Pd) to the mean pressure proximal stenosis, that is the mean pressure in the aorta (Pa), during maximal hyperaemia.
This is a comprehensive description of coronay lesion assessment from routinely used angiography to advanced imaging modalities like IVUS/OCT including their functional significance by FFR
Diagnostic catheters for coronary angiography Aswin Rm
Overview of diagnostic catheters used in coronary angiography
Guide catheters not included
History of coronary catheters
Radial techniques and catheters
Although the risks of coronary angiography have declined over the years by increased clinical experience and advanced technologies, it still requires attention, knowledge and experience due to being an interventional diagnostic method. A safe coronary angiography begins with the selection of the appropriate catheter for the anatomical structure of the patient and the evaluation of the pressure when the catheter is placed in the coronary ostium. Coronary pressure waves are complementary requirements of angiography. The recognition, evaluation and precautions to be taken for abnormal pressure waves directly affect the mortality of the patient. One of the first clues to the presence of stenosis in the left main coronary artery (LMCA) is abnormal changes in pressure when the catheter is seated in the ostial LMCA. This often occurs as a “ventricularization” or “damping”. For decades, ventricularization was mostly experienced as a stenosis by invasive cardiologists [1]. Recognition of abnormal changes in pressure and precautions to be taken prevent catastrophic outcomes in patients
https://crimsonpublishers.com/ojchd/fulltext/OJCHD.000518.pdf
For more open access journals in Crimson Publishers
please click on https://crimsonpublishers.com/
For more articles in open journal of Cardiology & Heart Diseases
please click on https://crimsonpublishers.com/ojchd/
Based on the principle that the distal coronary pressure measured during vasodilation is directly proportional to maximum vasodilated perfusion.
FFR is defined as the ratio of maximum blood flow in a stenotic artery to maximum blood flow in the same artery if there were no stenosis.
FFR is simply calculated as a ratio of mean pressure distal to a stenosis (Pd) to the mean pressure proximal stenosis, that is the mean pressure in the aorta (Pa), during maximal hyperaemia.
With advances in cardiology and cardiothoracic surgery, several newer implantable cardiac devices have become common in the surgical population. Multichamber pacemakers, implanted cardiac defibrillators and ventricular assist devices are frequent in current day practice. Many of the newer implantable cardiac electronic devices are targeted at managing heart failure. While managing such patients for non-cardiac surgeries, specific issues related to equipment characteristics and troubleshooting should be a priority for the anaesthesiologists. There is a possibility of malfunction of the devices resulting in catastrophic outcomes. Therefore, it is imperative to understand the pathophysiology, device characteristics and troubleshooting before embarking on anaesthetising patients with implantable cardiac electronic devices
A patient with pacemaker presents a complex challenge to the attending anaesthesiologist. The mode of management will be according to the type of pacemaker implanted. This presentation discusses in brief the peri-operative consideration in a patient with pacemaker.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
This is a presentation by Dada Robert in a Your Skill Boost masterclass organised by the Excellence Foundation for South Sudan (EFSS) on Saturday, the 25th and Sunday, the 26th of May 2024.
He discussed the concept of quality improvement, emphasizing its applicability to various aspects of life, including personal, project, and program improvements. He defined quality as doing the right thing at the right time in the right way to achieve the best possible results and discussed the concept of the "gap" between what we know and what we do, and how this gap represents the areas we need to improve. He explained the scientific approach to quality improvement, which involves systematic performance analysis, testing and learning, and implementing change ideas. He also highlighted the importance of client focus and a team approach to quality improvement.
The Art Pastor's Guide to Sabbath | Steve ThomasonSteve Thomason
What is the purpose of the Sabbath Law in the Torah. It is interesting to compare how the context of the law shifts from Exodus to Deuteronomy. Who gets to rest, and why?
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
3. Pacing impedance :
Pacing impedance refers to the opposition to
current flow.
Sources that contribute to pacing impedance:
1. Pacing lead conductor coil
2. Electrode-tissue interface
Normal lead impedance vary from 250-
1200ohms.
Single impedance value may be of little use
with out previous values for comparison.
4. Pulse generator output circuit
Capture threshold or Pacing threshold .
Minimum amount of energy required to constantly
cause depolarization
Voltage(mA) and pulse duration(mSec)
V=IR
5. 2.0 v 1.5 v 1 v
1. Pulse generator output circuit
6. 1. Pulse generator output
circuit
High Pacemaker Output can
cause
◦ Reduce longevity
◦ Diaphragmatic stimulation
◦ Muscle Sti. in Unipolar
pacemakers
◦ Patient may “feel” heart
beat
Electrical Testing Of Pacemaker
7. Electrical Testing Of Pacemaker
2. Pulse generator sensing circuit :
◦ Ability of the device to detect intrinsic beat of
the heart
◦ Measured - peak to peak magnitude (mv) &
slew rate(mv/ms)
8. Pulse generator timing circuit :
a. Lower rate limit (LRL)
b. Hysteresis rate
c. Refractory and blanking periods
d. Ventricular safety pacing interval .
e. Upper rate response .
Electrical Testing Of Pacemaker
9. Pulse generator timing circuit :
Lower rate interval - lowest rate that the pacemaker
will pace .
Escape interval:sensed beat to next paced beat.
A paced or non-refractory sensed event restarts the rate
timer at the programmed rate.
11. Pulse generator timing circuit :
Hysteresis :
Hysteresis allows the rate to drop below the programmed
pacing LRL.
Advantages of hysteresis :
1. Encourages native rhythm – maintain AV sync in VVI ,
prolong battery life
2. Prevent retrograde conduction – avoids pacemaker
syndrome
12. AV delay (AVI) – pacemaker equivalent of PR interval.
Sensed vs paced AVI – paced AVI is programmed at 125-
200ms , sensed AV interval is programmed at 20-50ms
shorter than paced.
Dynamic/adaptive AV delay :shorter AVI with increase in
heart rate,allow pacemaker to respond to exercise and
have better haemodynamics.
Pulse generator timing circuit :
sAVI – 150ms
pAVI – 200ms
13. AV delay (AVI)
Longer AVI :
Good AV conduction – maintains AV synchrony ,
long battery life
Achieved by following methods :Programming
longer AVI , managed ventricular pacing , AV delay
hysteresis .
Shorter AVI:
HOCM – RV apical pacing decreases HOCM gradient
CRT – usually 80-120ms , for 100%ventricular pacing
and optimize CO
Physiological response to faster heart rates can be
answered
Pulse generator timing circuit :
14. Refractory and
blanking
periods :
Refractory
period –
sensing present
but no action
Blanking period
- sensing
absent and
hence no action
Pulse generator timing circuit :
15. Blanking
period
Time Importance
Atrial blanking
period
50-100ms Non programmable ,
Avoid atrial sensing of its own
paced beat
Post ventricular
atrial blanking
period
220ms Avoid sensing of ventricular
beat
Long PVAB decreases
detection of AF,AFL
Ventricular
blanking period
50-100ms Non programmable,
Avoid ventricular sensing of
its paced beat
Post atrial
ventricular
blanking period
28ms if the PAvB period is too long,
R on T - ventricular
tachyarrhythmia.
16. Refractory period Importance
Ventricular refractory period
(VRP)
Prevent sensing of T wave
.
Atrial refractory period
(ARP)
AVI (120-200ms) .
Post ventricular atrial
refractory period
Avoid sensing retrograde P
waves (PMT) , far field R
waves .
Pulse generator timing circuit :
18. Rate responsive pacing refer to ability of pacemaker
to increase its lower rate in response to physiological
stimulus
Upper rate limit:important to prevent tracking of
rapid atrial activity like in AF
HRR should start with in 10s of exercise , peak at 90
– 120s and should return to baseline with in 60 –
120s after exercise.
If intrinsic atrial rate exceeds URR then wenckebach
or 2:1 AVB
Choosing URR : young patients (150b/mt) , old
angina (<110b/mt).
Various sensors (activity , minute ventilation , QT)
Rate smoothing: allows variation of R-R interval <6%
Pulse generator rate responsive pacing:
20. PACING MODES
BEPG(British pacing and electrophysiology
group)
NASPE(North American society of pacing
and electrophysiology)
DD I/T R
III-D(I+R) :dual tracking of atrial activity while
inhibited by ventricular activity
5th position: antitachycardia function(pacing/shock)
21. 5. Pulse generator modes switching:
Electrical Testing Of Pacemaker
DDD / VDD
Atial tachyarrythmias
Sensed atrial events
Trigger fast ventricular rates
Palpitations. Dyspnoea. And Fatigue.
DDIR /
VVIR
22. Pulse generator modes switching:
Programming mode switching Mode switching
occurs when the sensed atrial rate exceeds a programmed
atrial tachycardia detection rate. By definition, this value
must be faster than the URL (maximum tracking rate).
Atrial tachycardia detection is typically programmed to
175-l88bpm or thereabouts.AMS base rate is higher than
LRI.
23. Electrical Testing Of Pacemaker
Pacemaker follow up guidelines:
Single chambered
pacing
Dual chambered
pacing
1st month q 2 week 1st month q 2 weeks
2nd -48th month q 12
week
2nd – 30th month q
12weeks
49th – 72nd month q 8
week
31st – 48th month q 8
weeks
73rd month and later q 4
weeks
49th month and later q
4week
26. Pocket hematoma :
The risk of haematoma is increased in patients
taking antithrombotic or anticoagulant drugs
(Goldstein et al., 1998).
Most small hematomas can be managed
conservatively with cold compress and withdrawal
of antiplatelet or antithrombotic agents.
Occasionally, large hematomas that compromise
the suture line or skin integrity may have to be
surgically evacuated.
Needle aspiration increases risk of infection and
should not be done.
27. Pocket hematoma :
In patients requiring oral anticoagulants (warfarin), to
take INR of about 2.0 at the time of implantation is
safe (Belott & Reynolds, 2000).
Unfractionated heparin or low-molecular-weight
heparin are always discontinued prior to device implant
and ideally avoided for a minimum of 24 hours post
implantation.
Administration of anticoagulants can be resumed
within 48-72 h after implantation if there is no
evidence of substantial hematoma formation.
28. Device-related infections :
The reported incidence of pacemaker-related
infection ranges from 0.5% to 6% in early series.
The use of prophylactic antibiotics has decreased
the rate of acute infections following pacemaker
implantations to <1 to 2 percent in most series.
The mortality of persistent infection when infected
leads are not removed can be as high as 66%.
DM, malignancy, operator inexperience, advanced
age, corticosteroid use, anticoagulation, recent
device manipulation, CRF, and bacteremia from a
distant focus of infection.
30. Twiddler syndrome:
Obese women with loose, fatty subcutaneous tissue
Small size of the implanted generator with a large pocket
Twisting of pulse generator in long axis
Lead dislodgement and lead fracture
Failure to capture
31. The prevelance of this
syndrome is 0.07% (Gungor
et al., 2009)
Rotated along the transverse
axis it is referred by us as
the reel syndrome.
Pocket should be revised.
Avoid by
◦ Limit the pocket size,
◦ Suture the device to the
fascia
◦ The patients not to
manipulate their device
pocket
Twiddler syndrome:
32. Failure to capture
Failure to output
Sensing abnormalities(under and over
sensing)
Specific mode complications
1. Pacemaker related tachycardia
2. Pacemaker syndrome
PACEMAKER MALFUNCTION
33. Failure to capture:
Pacing artifact present but no evoked potential .
Causes
1. Lead dislodgement or perforation
2. Lead maturation(inflammation/fibrosis)(exit
block)
3. Battery depletion
4. Circuit failure(coil fracture , insulation defect)
5. Inappropriate programming(low output /pulse
width)
6. Pseudo malfunction(pacing during refractory
period)
7. Functional non capture(oversensing).
8. Metabolic , drugs , cardiomyopathies
34. Medication effect on Capture
Drugs that increase
capture threshold
Drugs that decrease
capture threshold
Amiodarone
Flecainide
Propafenone
Sotalol
Procainamide
lidocaine
Atropine
Epinephrine
Isoproterenol
corticosteroids
35. Electrocardiographic tracing from a patient with a DDDR pacemaker. All ventricular
pacing artifacts but one failed to result in ventricular depolarization—
that is, failure to capture
Failure to capture:
36. Failure to capture:
Pacing threshold
Normal Increased
Battery depletion
Functional non
capture
Impedance
Normal
Dislodgement
Exit block
Decreased
Insulation
failure/
break
Increased
Lead
fracture
Loose screw
37. Failure to output:
Absence of pacing stimuli and hence no capture .
Causes
1. Pseudo malfunction - hysteresis , PMT
termination , sleep rate
2. Over sensing - EMI ; T P R over sensing ;
Myopotential/diaphragmatic ; Cross talk .
3. Open circuit - lead fracture , loose screw ,
incompatible lead .
4. Battery depletion
5. Recording artifact.
38. Failure to output:
VVIR pacemaker This patient had a pacemaker programmed to a
unipolar sensing configuration. The sensing of myopotentials led to
symptomatic pauses, and reprogramming the pacemaker to a
bipolar sensing configuration prevented subsequent myopotential
over sensing.
39. Application of magnet
Failure to output:
Eliminates pauses Pauses persistent
Impedance
Normal
Decreased
Insulation
failure/break
Increased
Lead fracture
Loose screw
Battery
depletionOver sensing
Pseudo malfunction
40. Battery depletion :
Elective replacement indicators (ERI)
1. Low voltage(2.1-2.4V)
2. Low pacing rate on magnet application
3. Elevated battery impedance
4. Increased pulse width duration
5. Restricted programmability
6. Change to simpler pacing mode
End of life (EOL)
1. Low voltage(≤2.1vol)
41. Pacemaker undersensing :
Pulse artifact or intrinsic complex present but no
sensing(sensed beat doesn’t reset escape interval or
cycle).
Causes are
1. Defect in signal production – scar /fibrosis
following MI , ectopic , cardioversion,defibrillation ,
metabolic.
2. Defect in signal transmission – lead fracture
/dislodgement , insulation failure , partial open
circuit.
3. Defect in pacemaker – battery depletion , sensing
circuit abnormalities , committed DVI.
42. Pacemaker over sensing :
Inappropriate inhibition as
failure to pace
Causes
1. EMI
2. T , P , R over sensing .
3. Far field R wave
sensing(atrial).
4. Cross talk
5. Myopotential
(unipolar)
6. Make break signals
Cross talk :
High atrial output
High ventricular sensitivity
Low VBP
Ventricular sensing of paced
atrial impulse
Ventricular Asystole
45. Pacemaker Syndrome May Be Caused By:
Loss of capture, sensing
A-V intervals of long duration
Onset of 2:1 block
Single chamber system(VVI)
Absence of rate increase with exercise
ECG:Retrogradely conducted inverted P over T
CORRECTIVE ACTION:
◦ Reduce pacing rate.
◦ Hysteresis on to allow more sinus rhythm
◦ Shift to dual chamber pacing.
47. PMT is the Result of:
Also known as pacemaker re-entry
tachycardia or endless-loop tachycardia
(like other re-entry dysrhythmias,
pacemaker is now a part of the re-entry
circuit,Mostly anterograde limb of
reentrant tachycardia)
Retrograde conduction
PVARP
Tracking fast atrial rates (physiologic or
non-physiologic)
48. only in patients with dual chamber devices
The ventricular impulse is retrogradely
conducted via the AV node to the atria, now the
atrial lead senses the atrial impulse and
generates a ventriculair pulse (completed loop)
This pacemaker re-entry tachycardia will not
exceed the programmed upper rate, however
can be significant enough to cause symptoms
magnet therapy.
Pacemakers atrial sensing tresholds need to be
adjusted
Mode switch can cause the pacemaker to
discontinue atrial tracking when the atrial upper
rate is exceeded
49. Rate Drop Response
Delivers pacing at high rate when
episodic drop in rate occurs
Pacing therapy indicated for patients
with neurocardiogenic syncope
Rate Drop Response
50. Venous thrombosis :
Venous thrombosis occurs in 30% to 50% of patients
and only 1-3% of patients become symptomatic.
Manifestations vary from usually asymptomatic,
acute symptomatic thrombosis, and even SVCS .
Early or late after pacemaker implantation.
Predictors of severe stenosis are multiple pacemaker
leads , previous pacing , double coils , hormone
therapy .
Asymptomatic (no treatment) , symptomatic
(anticoagulants – endovascular stents – surgical
correction ).
51. Extracardiac stimulation
The diaphragm or pectoral or intercostal muscles
Diaphragmatic stimulation - direct stimulation of the
diaphragm (left) or stimulation of the phrenic nerve
(right).
Early postimplantation period , dislodgment of the
pacing lead.
MC in patients with LV coronary vein branch lead
placement for CRT
Output pacing importance (testing and treatment)
Pectoral stimulation - incorrect orientation of the
pacemaker or a current leak from a lead insulation
failure or exposed connector.
52.
53. PERIOPERATIVE MANAGEMENT
Require perioperative determination of pacemaker
dependency.
An external defibrillator should be close by.
Intraoperative management:
Application of magnet.
Perioperative reprogramming to
assynchronous mode.
Rate adaptive sensors should be disabled.
Oversensing of electrocautery is more common with
unipolar leads.
When external cardioversion is required ,defibrillation pads
should be placed at least 8 inches from the pulse
generator.