PACE MAKERS

PRESENTED BY:

MS. VINITA MASCARENHAS

F.Y. M.SC NURSING

S.N.D.T. WOMEN’S UNIVERSITY

L.T. COLLEGE OF NURSING.

CONDUCTION SYSTEM OF THE HEART:

ECG:

A HEALTHY HEART ECCG:

DEFINITION:

A CARDIAC PACEMAKER IS AN ELECTRONIC DEVICE, THAT DELIERS, DIRECT ELECTRICAL STIMULATION TO STIMULATE THE MYOCARDIUM TO DEPOLARIZE, INITIATING A MECHANICAL CONTRACTION.

THE PACEMAKER INITIATES AND MAINTAINS THE HEART RATE WHEN THE HEART’S NATURAL PACEMAKER IS UNABLE TO DO SO.

TYPES OF PACEMAKERS:

PERMANENT PACEMAKERS: SURGICALLY PLACED LEADS ARE PLACED TRANVENOUSLY, IN APPROPRIATE CHAMBER

OF THE HEART, AND THEN ANCHORED TO THE ENDOCARDIUM PULSE GENERATOR PLACE IN A POCKET IN THE SUBCUTANEOUS

TISSUE UNDER THE CLAVICLE OR ABDOMEN. MOSTLY USED FOR LONG-TERM , PATIENTS WITH CHRONIC HEART

CONDITIONS.

CONTD..

TEMPORARY PACEMAKER: PLACED EXTERNALLY. SERVE AS A BRIDGE, BETWEEN TEMPORARY AND PERMANENT

PACEMAKER.

METHODS OF PLACEMENT OF A TEMPORARY PACEMAKER:

TRANSVENOUS PACEMAKERS:

INSERTED TRANSVENOUSLY( USUALLY SUBCLAVIAN, INTERNAL JUGULAR, ANTECUBITAL OR FEMORAL), INTO THE RIGHT VENTRICLE( OR RIGHT ATRIUM) AND RIGHT VENTRICLE FOR DUAL- CHAMBER PACING. AND THEN ATTACHED TO AN EXTERNAL PULSE GENERATOR.

PROCEDURE DONE BEDSIDE OR UNDER FLUROSCOPY.

EPICARDIAC PACEMAKERS:

IN THIS CASE, THE WIRES ARE ATTACHED TO THE ENDOCARDIUM, AND ARE BROUGHT OUT THROUGH A SURGICAL INCISION IN THE THORAX.

THESE WIRES ARE CONNECTED TO AN EXTERNAL PULSE GENERATOR.

COMMONLY SEEN AFTER CARDIAC SURGERY.

TRANSCUTANEOUS PACING:

TRANSCUTANEOUS PACING:

NON- INVASIVE, MULTIFUNCTIONAL, ELECTRODE PADS ARE PLACED. PLACEMENT: ANTERIOR- POSTERIORLY, ANTERIOR- LATERALLY MULTIFUNCTIONAL ELECRODE PADS ARE THEN CONNECTED TO AN

EXTERNAL SOURCE( DEFIBRILLATOR WITH PACING ABILITY). THE EXTERNAL IMPULSE FLOWS THROUGH THE ELECTRODE PADS

AND SUBCUTANEOUS SKIN TO THE HEART. THUS PACING THE HEART.

TRANSTHORACIC PACING:

PLACED IN EMERGENCY, VIA A LONG NEEDLE, USING A SUBXYPHOID APPROACH.

THE WIRE IS THEN PLACED DIRECTLY INTO THE RIGHT VENTRICLE.

BIVENTRICULAR PACEMAKERS:

ALSO KNOWN AS CARDIAC RESYNCHRONIZATION. USED TO TREAT MODERATE TO SEVERE HEART FAILURE AS A RESULT

OF LEFT VENTRICULAR DYSSYNCHRONY. INTRAVENTRICULAR CONDUCTION DEFECTS RESULT IN AN

UNCORDINATED CONTRACTION OF THE LEFT AND RIGHT VENTRICLE, WHICH CAUSES A WIDE QRS COMPLEX AND IS ASSOCIATED WITH WORSENING HEART FAILURE AND MORTALITY.

BIVENTRICULAR PACEMAKERS CAN INCORPORATE IMPLANTABLE CARDIO-VERTER DEFIBRILLATORS OR CAN BE USED ALONE.

BIVENTRICULAR PACEMAKER:

PARTS OF A PACEMAKER DEVICE:

PULSE GENERATOR: IT CONSISTS OF A CIRCUITRY AND BATTERIES. IN A PPI, IT IS ENCAPSULATED IN A METAL BOX, EMBEDDED

UNDER THE SKIN. THE BOX PROTECTS THE GENERATOR FROM ELECTROMAGNETIC

INTERFERENCE AND TRAUMA. PPI USE LITHIUM BATTRIES. LIFE SPAN= 8-12 YRS. IN A TPM, THE GENERATOR IS A SMALL BOX WITH DIALS FOR

PROGRAMMING.TRANSCUTANEOUS PACING SYSTEMS, USE EXTERNAL SOURCE LIKE DEFIBRILLATOR WITH PACING ACTIVITY.

TPM USE BATTERIES WHICH NEED REPLACEMENT AS PER THE USE OF THE DEVICE.

TRANSCUTANEOUS SYSTEMS USE RECHARGEABLE BATTERY CIRCUITRY.

PACEMAKER LEAD:

TRANSMITS ELECTRICAL SIGNAL/ CURRENT FROM THE PULSE GENERATOR TO THE HEART.

TYPES OF PACEMAKER LEADS:

SINGLE CHAMBER PACEMAKER:

1 LEAD, EITHER IN ATRIAL OR VENTRICULAR CHAMBER.

SENSING AND PACING FUNCTIONS ARE CONFINED TO THE CHAMBER WHERE THE LEAD IS PLACED.

CONTD.. DUAL- CHAMBER PACEMAKER:

2 LEADS

ONE LEAD IN ATRIUM, OTHER IN VENTRICLE.

PACING AND SENSING OCCUR IN BOTH HEART CHAMBERS, MIMICKING THE PHYSIOLOGICAL PACING.

CONTD.. BIVENTRICULAR PACEMAKER:

3 LEADS- ONE LEAD IN RT. ATRIUM, ONE LEAD IN RT. VENTRICLE AND ONE LEAD IN LT. VENTRICLE.

CONTD..

IN SINGLE RIGHT VENTRICLE PACING, THERE IS SLIGHT DELAY OF THE LEFT VENTRICLE CONTRACTING, AS THE ELECTRICAL IMPULSE BEGINS IN THE RIGHT VENTRICLE AND MOVES IN THE LEFT VENTRICLE, GIVING A LEFT BUNDLE BRANCH BLOCK APPEARANCE.

BY PACING BOTH VENTRICLES AT THE SAME TIME,THE PACEMAKER CAN RESYNCHRONIZE THE HEART.

CONTD.. APPROACH: LEADS MAY BE INSERTED VIA A VEIN, INTO THE RT. ATRIUM/ RT. VENTRICLE, OR DIRECT PENETRATION INTO THE CHEST WALLAND ATTACHED TO THE LT. VENTRICLE OR RT. ATRIUM. FIXATION DEVICE: LOCATED AT THE END OF THE PACEMAKER LEAD, ALLOW FOR SECURE ATTACHMENT TO THE HEART, REDUCING THE POSSIBILITY OF LEAD DISLODGEMENT.

TEMPORARY LEADS: CONNECTED TO EXTERNAL PULSE GENERATOR AND PROTRUDEFROM THE INCISION.PERMANENT LEADS ARE CONNECTED TO PULSE GENERATOR IMPLANTED UNDER THE SKIN.

INDICATIONS: SYMPTOMATIC BRADYDYSRTHYTHMIAS. SINUS BRADYCARDIA DUE TO DRUG THERAPY. HEART BLOCK HYPERSENSITIVE CAROTID SINUS SYNDROME AND

NEUROCARDIOGENIC SYNCOPE. PROPHYLAXIS( PRIOR CARDIAC SX, POST ACUTE MI) DIAGNOSTIC TESTS: CARDIAC CATHETERIZATION PTCA/ STRESS TEST/ PRIOR TO PERMANENT PACING TACHYDYSRHYTHMIAS( SVT, VT)

FUNCTIONS OF A PACEMAKER:

CARDIAC PACING STIMULATES EITHER THE ATRIUM, VENTRICLE OR BOTHIN SEQUENCE, AND INITIATES ELECTRICAL DEPOLARIZATION AND CARDIAC CONTRACTIONS.

CARDIAC CONTRACTIONS ARE EVEDENCED ON THE ECG BY THE PRESENCE OF “A SPIKE”, OR “PACING ARTIFACT”.

PACING FUNCTIONS:

1. ATRIAL PACING: DIRECT STIMULATION OF THE RT.

ATRIUM, PRODUCING A “SPIKE” ON THE ECG PRECEDING A P WAVE.

2. VENTRICULAR PACING:

DIRECT STIMULATION TO OF THE RIGHT OR LEFT VENTRICLE PRODUCING A “SIPKE”, ON THE ECG PRECEEDING A QRS COMPLEX.

3. AV PACING:

DIRECT STIMULATION TO THE RIGHT ATRIUM, AND EITHER VENTRICLE IN SEQUENCE; MIMICS NORNAL CARDIAC CONDUCTION, ALLOWING THE ATRIA TO CONTRACT BEFORETHE VENTRICLES TO INCREASE CARDIAC OUTPUT.

SENSING FUNCTIONS: CARDIAC PACEMAKERS SENSE THE INTRINSIC CARDIAC ACTIVITY.

1. DEMAND: ABILITY TO “ SENSE” INTRINSIC CARDIAC ACTIVITY AND DELIVER A PACING STIMULUS ONLY IF THE HEART RATE FALLS BELOW THE PRESET RATE.2. FIXED: NO ABILITY TO “SENSE” INTRINSIC CARDIAC ACTIVITY. THE PACEMAKER CANT “” WITH THE HEARTS NATURAL ACTIVITY AND CONTINOUSLY DE LIVERS ASYNCHRONIZE PACING STIMULUS AT A PRESET RATE.3. TRIGGERED: ACTIVITY TO DELIVER PACING STIMULI IN A RESPONSE TO “ SENSING” A CARDIAC EVENT.

CONTD.. 1. “SEES”---ATRIAL ACTIVITY AND DELIVERS A PACING SPIKE TO THE

VENTRICL AFTER AN APPROPRIATE DELAY(0.16 SEC). 2. MAINTAIN AV SYNCHRONY AND INCREASE HEART RATE BASED ON

INCREASES IN THE BODY DEMANDS,THAT OCCUR DURING EXERCISE OR DURING STRESS.

3. “PHYSIOLOGICAL” SENSORSARE BEING DEVELOPED AS ALTERNATIVES TO “TRIGGER” A VENTRICULAR RESPONSE BECAUSE MANY PATIENTS HAVE ATRIAL DYSFUNCTION.

4. “ SENSOR- DRIVEN” RATE RESPONSIVE PACEMAKERS DO NOT SENSE ATRIAL ACTIVITY, A TRIGGERED VENTRICULAR BEAT OCCURS WHEN THE PACEMAKER SENSES EITHER INCREASE IN MUSCLE ACTIVITY, TEMPERATURE, O2 UTILIZATION,OR CHANGES IN BLOOD PH.

CAPTURE FUNCTIONS:

THE PACEMAKERS ABILITY TO GENERATE A RESPONSE FROM THE HEART (CONTRACTION), AFTER ELECTRICAL STIMULATION IS REFFERED TO AS CAPTURE.

CAPTURE IS DETERMINED BY THE STRENGTH OF THE ELECTRICAL STIMULUS, MEASURED IN mA, THE AMOUNT OF TIME THE STIMULUS IS APPLIED T THE HEART AND BY CONTACT OF THE DISTAL TIP OF THE PACING LEAD TO THE MYOCARDIAL TISSUE.

(A) ELECTRICAL: INDICATED BY A P WAVE OR QRS FOLLOWED BY A PACEMAKER SPIKE.

(B) MECHANICAL: PALPABLE PULSE CORRESPONDING TO THE ELECTRIC EVENT.

CONTD…

PACEMAKER CODES:

THE INTESOCIETY COMMISSION FOR HEART DISEASE(ICHD) HAS ESTABLISHED A 5- LETTER CODE TO DESCRIBE THE NORMAL FUNCTIONIN OF THE PACE MAKER

COMPLICATIONS:

1. ASYSTOLE FOLLOWING ABRUPT CESSATION OF PACING. 2. ACCELARATION OF EXISTING TACCHYCARDIABOR

FIBRILLATION. 3. DISCONNECTION OF LEAD SYSTEM. 4. BREACH IN THE LEAD SYSTEM– THUS CAUSING LOSS OF

CAPTURE OR SENSING---- CAUSING FIBRILLATION--- PERICARDITIS.

RESEARCH: Johns Hopkins heart researchers are unravelling the mystery of

how a modified pacemaker used to treat many patients with heart failure, known as cardiac resynchronization therapy (CRT), is able to strengthen the heart muscle while making it beat in a coordinated fashion.

The researchers also identified an enzyme that mimics this effect of CRT without use of the device.

By studying isolated muscle tissue and muscle cells, they examined the relationship between contraction and the calcium that triggers it. In the hearts that beat out of sync, force from the muscle cells and the level of calcium needed to generate contractions were very much reduced. CRT improved contraction force more than calcium, and this led to the discovery that CRT had increased the sensitivity of the muscle to calcium.

CONTD.. Working with heart muscle and isolated cells from the same

animal models, the researchers found that the enzyme turned out to be GSK-3 beta, which was able to convert the behavior of muscle cells from a heart that was beating out of sync to what looked like heart cells that had received CRT, essentially mimicking the effect of CRT.

GSK-3 beta was inactive in muscle from a failing and dyssynchronous heart, it was reactivated by CRT. When that happened, the enzyme altered the motor proteins so that they generated greater force using the same amount of calcium- based activation.

Nearly all existing medications for heart failure increase heart contraction by enhancing levels of calcium available to muscle cells, but over time, these higher levels can be toxic to the heart.

RESEARCH 2: . In a study published in 2011, Kass and colleagues also showed

that CRT enables heart muscle to respond to hormones, such as adrenaline, which stimulates pumping ability, in a similar way to what happens during exercise.

ASSIGNMENT: “A” TACHYDYSRHYTHMIA DISCONNECTION OF LEAD INTERSOCIETY COMMISSION FOR

HEART DISEASE. ONE LEAD IN RA, RV LV SPIKE ON ECG PRECEEDING QRS

COMPLEX 5mA

“B” BIVENTRICULAR PACEMAKER OUTPUT OF TEMPORARY

PACEMAKER SVT AND VT COMPLICATION OF PACEMAKER PACEMAKER CODES VENTRICULAR PACING. TRIGGER FUNCTION

BIBLIOGRAPHY: NETTINA M. SANDRA, LIPPINCOTT MANUAL OF NURSING PRACTICE,

10TH EDITION, WOLTERS KLUWER (INDIA), PVT LTD, NEW DELHI, 2014, PG NO: 248-256.

BLACK M. JOYCE, HAWKS HOKANSON JANE, MEDICAL- SURGICAL NURSING: CLINICAL MANAGEMENT OF POSITIVE OUTCOME, 7TH EDITION, SAUNDERS ELSEIVER PUBLICATIONS, NEW DELHI, 2005, PG NO: 1548-1559.

SCHEETZ LINDA, EDITOR, CRITICAL CARE NURSING SECRETS, NEW JERSEY, MOSBY, 2006, PG NO:28-34.

JACOB ANNAMMA, EDITOR, CRITICAL CARE PROCEDURE: THE ART OF NURSING PRACTICE, 2ND EDITION, NEW DELHI, JAYPEE BROTHERS MEDICAL PUBLISHERS, 2010, PG NO: 381-386.

INTERNET SOURCES: www.emedicine.Medscape.com www.youtube.com www.Wikipedia.com

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